Date   

Tek 371 test fixture

oliver johnson
 

I am working on a tek 371 with a friend of mine , it has no test fixture and these things are never seen on ebay , so our idea is to make one . We are in the process of using a test fixture which will be modded to house a transistor with sense leads .

I am wondering that because this is a high current and high voltage setup what would be an appropriate wire in addition would the length be critical for accuracy, i do not have a unit to look at so i assume all as it relates to designing on that will perform well .
If someone has some experience with this unit could you chime in and explain as much as you can , or if pictures are possible of the inner workings that would help. Thanks .


Re: how high would you stack them?

 

Hi John,

Interesting question!

33 years ago my wife and I agreed to split our residential office 50/50. I gradually appropriated about 2/3rds of it. At first I had plenty of room. Then I had test equipment on each desk. My desks wrap around roughly 300 degrees, and I sit in the middle. Of course eventually I ran out of desk surface. Then I had to go up since under all of my desks there were shelves or filing cabinets.

Right now my desks have TM5006's stacked either four or five high. I have full height 7K scopes two high. I am pretty much at my limit. Any higher and the top row of instruments would be at an awkward height above eye level.

I have so much equipment stacked this way on my desks that I was definitely concerned about the floor not being able to handle the load. During our remodel a few years ago I had the floor reinforced for peace of mind.

I have several friends with four or more filled full height racks, plus other test equipment on their desk(s) so other than my "Test Equipment Figure of Merit" (TEFM) being higher than theirs I'm not alone in this respect. You can calculate your own personal TEFM as follows
TEFM = (Your Test Equipment Volume) / (Total Volume of your lab - space you occupy).
An ideal TEFM would be between 0.5 and 0.75. In my case I have been out of room for a long time and more stuff keeps appearing so I'm above 0.95 and drowning in unfinished projects and equipment waiting to be fixed so I can get it out of here.

Whatever makes you happy!

Dennis Tillman W7PF

-----Original Message-----
From: John Ferguson via Groups.Io
Sent: Friday, November 02, 2018 12:13 PM
Subject: [TekScopes] how high would you stack them?

I apologize for my simplicity, but I have height but not a lot of bench
space. It occurred to be that there might be a limit to haw many scopes/
TM's one might stack so the question is what are you guys doing.

I have a TM 504 with full load of modules on top of bench with a 2445B,
next, and then a 2465. I would like to stack another 2445b on top of
that. (Don't ask why I have 3 similar scopes - they sort of followed me
home [legally])

It looks like putting the TM504 on top would make most sense weight wise,
but would make it harder to see screen on bottom scope.

What is most number of these things you'd put atop a very substantial
bench?
john



--
Dennis Tillman W7PF
TekScopes Moderator


Re: 425 Mil vertical module needed....seeking

Jack
 

Hi Harvey..of course take your point on the final comment you made...whether the depot has 'everything needed' to test
the card to environmental spec was in my mind. I suppose in a way it's like say the ART-13 or BC-348...serviced by depot
but post WW11 some number were completely refurbished for Pan Am and other airlines, which may have required (speculating)
testing in actual conditions to warranty their reliability. Finding a defective part is finding a defective part..and replacing it..is
same wherever done. Military designed some redundant circuitry I believe but I wonder...when your blokes repaired at
component level, did they also replace a string of components say between the crook one and the next junction or just the dud?

I experienced the easy-extraction system system with the URR391 for example but my experience with CRO's outside of the odd occasion
is quite small.

My regards

-----Original Message-----
From: Harvey White
Sent: Saturday, November 3, 2018 9:51 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

On Sat, 3 Nov 2018 04:16:17 +1000, you wrote:

You'd be surprised that the basic difference (perhaps) in the MIL
units vs. the commercial units is the ability to remove subsystems.
This does not always follow with (for instance), TM500 and TM5000
series. Scopes, however, I'm willing to go with a different model.

Having said that, the schematics are often quite similar, and if you
can repair a MIL unit without black boxing it, you can repair a
civilian unit (especially by swapping boards.... <innocent look>).

The similarity happens when you do what's equivalent to depot level
test (and my job was mostly designing flightline test equipment).
Regardless of the complexity of the item, once you start to diagnose
down to a component (if possible), it's really the same thing,
regardless of where it happens, depot, manufacturer's testing and
rework, or your own lab.

Harvey


Hi thanks Harvey....yes that's about it.....time saving with a good spares
inventory ....replace the faulty aspect of equipment and then send through
the system
to component level repairs. Repair was not always attempted and "U/S" tags
were plentiful. Reliability and cost were a decision. I recall when aircraft
mods were
done in Vietnam conflict we just dumped $millions in unusable inventory,
even here. Our (Defence's) vibration and environmental equipment was given
to AWA,
which then charged Defence for the use of it. I found that..a kind-of
peculiar arrangement. Labour costs yes, but use of the gear wasn't confined
to us.

Component level was not always done at Echelon...a level of testing might be
done and a decision made whether to send to the manufacturer but at the card
level
when it was a card....it may more likely have been tagged 'U/S' scrupulously
recorded then binned, later ...perhaps many years later and when security
allowed it and the
conflict was over.....go through the 'disposals auctions'. The equipment
need to ensure the gear met services' specs was too complex and expensive in
some cases.
Reliability warrantied as being certain is primary especially in weaponry
and radar you mentioned demands manufacturer-level accuracy. My recollection
is that
it was not until after 'Korea' thatmodularisation became common...the TRC77
for example in a small way. Until then changing tubes was the field level
repair.

Owing to advice from Dinos I was able to realise what I thought a nightmare,
highly inefficient teardown for a small repair was in fact simple...It took
about 10 minutes
pull the module once the advice I was given made sense...in the field with
spares available it was probably a half hour turnaround. Edgar Allen Poe's
fear of the Raven
tapping at his door was no greater than my fear of Tektronix CRO's tapping
at my confusion of fear and lust when a Tektronix came sashaying into view.
"The best way
to get away from temptation is to give into it" wrote Oscar
Wilde,,,"Resist it, and your soul grows sick with longing for the things it
has forbidden to itself "
That is mankind's Achille's heel.

One look inside a Tektronix when I was 20 scared me into a sort of misty
coma...Milspec radio's...ok....general test equipment ok...BWD CRO's....well
ok. Tektronix
aaaaaaaaaaaaagh!! A contact with Tektronix supervisor out at Nth Ryde forty
years ago led to hair-raising information on repair costs. I can only thank
heaven and
Dinos and Fabio that I bought a Mil unit, unwitting of its advantages. What
I thought would be a simple repair isn't at component level but IS at module
level.

Reading some of the problems raised even in my brief experience with
tekscopes made it clear that this group is an essential part of dealing with
Tektronix gear.
One day I suppose, the manufacturers of Prozac and Zoloft will try to buy it
out, owing to the business they are losing through the support given each
other in forum.
Voila

-----Original Message-----
From: Harvey White
Sent: Thursday, November 1, 2018 9:38 AM
To: TekScopes@groups.
Cc: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

On Wed, 31 Oct 2018 08:56:47 -0700, you wrote:

Many of the functions of a Mil qualified piece of test equipment (or
flightline, I'm extrapolating from that) are as follows:

1) mil qualified parts (for TTL, for instance, expanded temperature
range and +/- 0.5 volt tolerance on VCC rather than 0.25 volts)

2) vibration and temperature tolerances

3) (perhaps most important): the ability to repair a unit by (on the
flightline) by replacing an whole unit, for instance, a complete power
supply, or a vertical channel, or a CRT/display unit, that kind of
thing.

This is, I suspect, where the (apparently) massive difference in
physical construction might come from.

Diagnostics wise, you'd go out to the aircraft, diagnose the radar,
and find out what is malfunctioning (transmitter, receiver, processor,
etc).

You'd black box replace the entire unit.

That unit would go back to the depot. At the depot, special test
equipment (bought from the radar's manufacturer) would diagnose the
failing unit to a particular board. That board would be replaced and
the unit would be re-tested. The failing board would go back to the
manufacturer for testing and repair.

Sound familiar?

I'm suspecting that the physical construction of this scope allowed
this kind of repair. Not sure, though.

Harvey


Hello Jack,

What you refer to as 425 Mil is, for correctness sake, a 465M or an AN/USM
425.
It confused me at first, as I didn't recall there was ever a 425
oscilloscope.
For what I know, the 465M is electronically similar to the civilian 465
(but even at electronic diagram level, there ARE differences), but, for the
sake of assemblies or sub-assemblies, they're essentially two completely
different oscilloscopes (i.e the boards are physically different).

As mentioned on this (http://w140.com/tekwiki/wiki/465M) page of the
TekWiki website, the 465M is more similar to the civilian 455, than it is
to the 465.
I can't really tell by how much they are similar, but you may be able to
compare them by yourself by looking at the service manuals of both, which
are available on the TekWiki website.
The page for the civilian 455 is here: http://w140.com/tekwiki/wiki/455

I don't know much of either (455 or 465M) but, coincidentally, there's a
seller on a Brazilian auction site, selling the modules of a Tektronix 455:

https://produto.mercadolivre.com.br/MLB-962333741-modulos-do-osciloscopio-tektronix-455-_JM

I can't tell how similar those modules are (to your 465M) and if they can
serve as parts donors, but if you find out that they may help, you can try
to contact the seller, or I can help you with the purchase and shipping of
the module (or the parts) to your location, for their advertised cost and
shipping expenses to your place.

Note: I have no affiliation with the seller (and don't even know if I know
them, since the auction site only reveals the seller after you purchase the
item).

I normally wouldn't even make this offer, as shipping from Brazil is
usually prohibitive and the parts are not even mine... But since you're so
far away down under, I think that shipping from anywhere will be just as
difficult.

Please let me know if you want my help, or maybe some other folks in the
group will chime.

Krgrds,

Fabio






On Tue, Oct 30, 2018 at 06:52 PM, Jack wrote:


Hi. I'm a new member finding my way. I bought a lot of Tektronix scopes
for
the services when with Defence during Vietnam era and visited Tektonix at
North Ryde (NSW)
to see about repairs to (I think it's a 564) I still have....still not
working
I guess after having a new very high voltage insulated transformer wound
for
CRT filament...two actually, the other must be around "somewhere". I
developed a healthy fear of Tektronic CRO's owing to the prices Tektronix
charged for repairs..

I have a 425 Mil with broken switch.in Vertical section It's
unrepairable.
Whilst I could sooner or later find a parts CRO, sight unseen on eBay for
example, it may also be on the way out. I think the plastic used in
Tektronix
may be the lowest quality amongst high quality devices , or maybe they
just
specify 'shall be or a type formula and manufacture which will maintain
all
utility until the end of time'

I was directed to your group (Hi...there) . To get to the essential point
Would some person have a reasonably low mileage vertical module,
complete,
which I could buy? Please advise me if so....Australia would be best of
course
but 'anywhere'. Also...to undo some confusion...I've been told 425 and
465 are
"intrinsically" the same CRO...obviously without the Mil labelling... .
Does
that mean parts are interchangeable?

One reason I ask is that I was also told that the 425 being Military
contract
and Mil Spec was built to be readily pulled down for field repairs. Is
that
true?...Is that a quality the 465 does not replicate? if so it may mean
that
...just as an example...the vertical amp module from a 465 may have some
mounting differences from the 425.

On the other hand it may not. Perhaps someone familiar with this type
will
bring me to a state of awareness even wisdom regarding my CRO. ...oh...
other
than having one channel down it seems to work ok and 'oh' again...when I
originally pulled it down a piece of curved springy metal fell out.
Whence it
exactly originated I have no idea...'somewhere inside'. .It may be a
method
of maintaining the case at frame potential, under pressure as one
reassembles
the CRO...so perhaps it 'jammed' between a plate on the chassis and the
bottom cover. It could have come from elsewhere or it might not be from
the
CRO at all.....That said, Im pretty sure I saw an exploded view one time
where
this curved metal piece as shown hanging in mid-air underneath the
chassis.
Have I been able to find that particular exploded view again (that was 3
years
ago)...of course not!!

Any passing of knowledge wisdom common sense mindfulness and most of all
perhaps a complete vertical amplifier will be very well received.
--
Jack







--
Jack


Re: how high would you stack them?

Harvey White
 

On Fri, 2 Nov 2018 15:12:44 -0400, you wrote:

I apologize for my simplicity, but I have height but not a lot of bench
space. It occurred to be that there might be a limit to haw many scopes/
TM's one might stack so the question is what are you guys doing.

I have a TM 504 with full load of modules on top of bench with a 2445B,
next, and then a 2465.  I would like to stack another 2445b on top of
that.  (Don't ask why I have 3 similar scopes - they sort of followed me
home [legally])

It looks like putting the TM504 on top would make most sense weight
wise, but would make it harder to see screen on bottom scope.

What is most number of these things you'd put atop a very substantial bench?
Because the bottom layer is either a 7000 scope, or the equivalent in
height, with one or two layers of test equipment beyond that.... by
the time I get to the third layer, it really wants to be storage. It's
a height issue due to how high I wish to look, rather than mechanical
(I use individual steel shelves where needed).

Harvey



john




Re: No contribution from David Hess since July 18th

Michael A. Terrell
 

These connectors are for CATV trunk and feeder lines. They are a special ceramic that expands while heated, and grip the outer aluminum so tight that it will break before it sucks out during a sudden temperature drop. They are installed with an open flame from a propane torch. You tighten the connector to the housing, prep the hardline and slip into the connector as soon as it is hot enough. After it cools, you tighten the center conductor. They are very RF tight, and have a very small insertion loss, or much of an impedance bump. I believe the ones we used were from Raychem, which specialized in Aircraft and Military connectors.


Michael A. Terrell

-----Original Message-----
From: Jack <goldmort@onthenet.com.au>
Sent: Nov 2, 2018 6:53 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] No contribution from David Hess since July 18th

Hi Michael....can one buy "pre-shrunk" wire (which actually means before it
is shrunk but going along your lines...)to fit into the pre-shrunk heat
shrink?

-----Original Message-----
From: Michael A. Terrell
Sent: Saturday, November 3, 2018 5:25 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] No contribution from David Hess since July 18th

I guess that you've never seen the heat shrink connectors for .500, .750 or
larger hardline that have to be heated to allow you to slide the cable into?
They are pre-shrunk.


Michael A. Terrell


Re: 425 Mil vertical module needed....seeking

Harvey White
 

On Sat, 3 Nov 2018 04:16:17 +1000, you wrote:

You'd be surprised that the basic difference (perhaps) in the MIL
units vs. the commercial units is the ability to remove subsystems.
This does not always follow with (for instance), TM500 and TM5000
series. Scopes, however, I'm willing to go with a different model.

Having said that, the schematics are often quite similar, and if you
can repair a MIL unit without black boxing it, you can repair a
civilian unit (especially by swapping boards.... <innocent look>).

The similarity happens when you do what's equivalent to depot level
test (and my job was mostly designing flightline test equipment).
Regardless of the complexity of the item, once you start to diagnose
down to a component (if possible), it's really the same thing,
regardless of where it happens, depot, manufacturer's testing and
rework, or your own lab.

Harvey


Hi thanks Harvey....yes that's about it.....time saving with a good spares
inventory ....replace the faulty aspect of equipment and then send through
the system
to component level repairs. Repair was not always attempted and "U/S" tags
were plentiful. Reliability and cost were a decision. I recall when aircraft
mods were
done in Vietnam conflict we just dumped $millions in unusable inventory,
even here. Our (Defence's) vibration and environmental equipment was given
to AWA,
which then charged Defence for the use of it. I found that..a kind-of
peculiar arrangement. Labour costs yes, but use of the gear wasn't confined
to us.

Component level was not always done at Echelon...a level of testing might be
done and a decision made whether to send to the manufacturer but at the card
level
when it was a card....it may more likely have been tagged 'U/S' scrupulously
recorded then binned, later ...perhaps many years later and when security
allowed it and the
conflict was over.....go through the 'disposals auctions'. The equipment
need to ensure the gear met services' specs was too complex and expensive in
some cases.
Reliability warrantied as being certain is primary especially in weaponry
and radar you mentioned demands manufacturer-level accuracy. My recollection
is that
it was not until after 'Korea' thatmodularisation became common...the TRC77
for example in a small way. Until then changing tubes was the field level
repair.

Owing to advice from Dinos I was able to realise what I thought a nightmare,
highly inefficient teardown for a small repair was in fact simple...It took
about 10 minutes
pull the module once the advice I was given made sense...in the field with
spares available it was probably a half hour turnaround. Edgar Allen Poe's
fear of the Raven
tapping at his door was no greater than my fear of Tektronix CRO's tapping
at my confusion of fear and lust when a Tektronix came sashaying into view.
"The best way
to get away from temptation is to give into it" wrote Oscar
Wilde,,,"Resist it, and your soul grows sick with longing for the things it
has forbidden to itself "
That is mankind's Achille's heel.

One look inside a Tektronix when I was 20 scared me into a sort of misty
coma...Milspec radio's...ok....general test equipment ok...BWD CRO's....well
ok. Tektronix
aaaaaaaaaaaaagh!! A contact with Tektronix supervisor out at Nth Ryde forty
years ago led to hair-raising information on repair costs. I can only thank
heaven and
Dinos and Fabio that I bought a Mil unit, unwitting of its advantages. What
I thought would be a simple repair isn't at component level but IS at module
level.

Reading some of the problems raised even in my brief experience with
tekscopes made it clear that this group is an essential part of dealing with
Tektronix gear.
One day I suppose, the manufacturers of Prozac and Zoloft will try to buy it
out, owing to the business they are losing through the support given each
other in forum.
Voila

-----Original Message-----
From: Harvey White
Sent: Thursday, November 1, 2018 9:38 AM
To: TekScopes@groups.
Cc: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

On Wed, 31 Oct 2018 08:56:47 -0700, you wrote:

Many of the functions of a Mil qualified piece of test equipment (or
flightline, I'm extrapolating from that) are as follows:

1) mil qualified parts (for TTL, for instance, expanded temperature
range and +/- 0.5 volt tolerance on VCC rather than 0.25 volts)

2) vibration and temperature tolerances

3) (perhaps most important): the ability to repair a unit by (on the
flightline) by replacing an whole unit, for instance, a complete power
supply, or a vertical channel, or a CRT/display unit, that kind of
thing.

This is, I suspect, where the (apparently) massive difference in
physical construction might come from.

Diagnostics wise, you'd go out to the aircraft, diagnose the radar,
and find out what is malfunctioning (transmitter, receiver, processor,
etc).

You'd black box replace the entire unit.

That unit would go back to the depot. At the depot, special test
equipment (bought from the radar's manufacturer) would diagnose the
failing unit to a particular board. That board would be replaced and
the unit would be re-tested. The failing board would go back to the
manufacturer for testing and repair.

Sound familiar?

I'm suspecting that the physical construction of this scope allowed
this kind of repair. Not sure, though.

Harvey


Hello Jack,

What you refer to as 425 Mil is, for correctness sake, a 465M or an AN/USM
425.
It confused me at first, as I didn't recall there was ever a 425
oscilloscope.
For what I know, the 465M is electronically similar to the civilian 465
(but even at electronic diagram level, there ARE differences), but, for the
sake of assemblies or sub-assemblies, they're essentially two completely
different oscilloscopes (i.e the boards are physically different).

As mentioned on this (http://w140.com/tekwiki/wiki/465M) page of the
TekWiki website, the 465M is more similar to the civilian 455, than it is
to the 465.
I can't really tell by how much they are similar, but you may be able to
compare them by yourself by looking at the service manuals of both, which
are available on the TekWiki website.
The page for the civilian 455 is here: http://w140.com/tekwiki/wiki/455

I don't know much of either (455 or 465M) but, coincidentally, there's a
seller on a Brazilian auction site, selling the modules of a Tektronix 455:

https://produto.mercadolivre.com.br/MLB-962333741-modulos-do-osciloscopio-tektronix-455-_JM

I can't tell how similar those modules are (to your 465M) and if they can
serve as parts donors, but if you find out that they may help, you can try
to contact the seller, or I can help you with the purchase and shipping of
the module (or the parts) to your location, for their advertised cost and
shipping expenses to your place.

Note: I have no affiliation with the seller (and don't even know if I know
them, since the auction site only reveals the seller after you purchase the
item).

I normally wouldn't even make this offer, as shipping from Brazil is
usually prohibitive and the parts are not even mine... But since you're so
far away down under, I think that shipping from anywhere will be just as
difficult.

Please let me know if you want my help, or maybe some other folks in the
group will chime.

Krgrds,

Fabio






On Tue, Oct 30, 2018 at 06:52 PM, Jack wrote:


Hi. I'm a new member finding my way. I bought a lot of Tektronix scopes
for
the services when with Defence during Vietnam era and visited Tektonix at
North Ryde (NSW)
to see about repairs to (I think it's a 564) I still have....still not
working
I guess after having a new very high voltage insulated transformer wound
for
CRT filament...two actually, the other must be around "somewhere". I
developed a healthy fear of Tektronic CRO's owing to the prices Tektronix
charged for repairs..

I have a 425 Mil with broken switch.in Vertical section It's
unrepairable.
Whilst I could sooner or later find a parts CRO, sight unseen on eBay for
example, it may also be on the way out. I think the plastic used in
Tektronix
may be the lowest quality amongst high quality devices , or maybe they
just
specify 'shall be or a type formula and manufacture which will maintain
all
utility until the end of time'

I was directed to your group (Hi...there) . To get to the essential point
Would some person have a reasonably low mileage vertical module,
complete,
which I could buy? Please advise me if so....Australia would be best of
course
but 'anywhere'. Also...to undo some confusion...I've been told 425 and
465 are
"intrinsically" the same CRO...obviously without the Mil labelling... .
Does
that mean parts are interchangeable?

One reason I ask is that I was also told that the 425 being Military
contract
and Mil Spec was built to be readily pulled down for field repairs. Is
that
true?...Is that a quality the 465 does not replicate? if so it may mean
that
...just as an example...the vertical amp module from a 465 may have some
mounting differences from the 425.

On the other hand it may not. Perhaps someone familiar with this type
will
bring me to a state of awareness even wisdom regarding my CRO. ...oh...
other
than having one channel down it seems to work ok and 'oh' again...when I
originally pulled it down a piece of curved springy metal fell out.
Whence it
exactly originated I have no idea...'somewhere inside'. .It may be a
method
of maintaining the case at frame potential, under pressure as one
reassembles
the CRO...so perhaps it 'jammed' between a plate on the chassis and the
bottom cover. It could have come from elsewhere or it might not be from
the
CRO at all.....That said, Im pretty sure I saw an exploded view one time
where
this curved metal piece as shown hanging in mid-air underneath the
chassis.
Have I been able to find that particular exploded view again (that was 3
years
ago)...of course not!!

Any passing of knowledge wisdom common sense mindfulness and most of all
perhaps a complete vertical amplifier will be very well received.
--
Jack



Re: No contribution from David Hess since July 18th

 

On Fri, Nov 2, 2018 at 08:05 PM, Dennis Tillman W7PF wrote:


Welcome to the 21st century where our members are spread around the globe and
local time is a myth and UTC is the only way to avoid confusion. But that
creates its own problems as was evident in this case.
I think that the use of UTC + offset and communicating that offset would *avoid* these problems for all systems and persons involved and not create any. All systems and persons would include users, contributors, databases, search systems etc.

Raymond


Re: 425 Mil vertical module needed....seeking

Jack
 

Hi again Michael...I will not go any further with the reply I sent you on TREC77 as it dawned on me (I'm a bit slow) that it is not connected to the Tektronix
but happy to hear more on my own email if you wish.

-----Original Message-----
From: Michael A. Terrell
Sent: Saturday, November 3, 2018 5:17 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

Did you mean the PRC77? if so, both of its predecessors, the PRC10 and the PRC25 were module based radios that were designed to be repaired by swapping in spare, pre-tuned modules. I did Interchangeability testing on the PRC77, along with final test at the Cincinnati Electronics factory.


Michael A. Terrell


-----Original Message-----
From: Jack <goldmort@onthenet.com.au>
Sent: Nov 2, 2018 2:16 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

Hi thanks Harvey....yes that's about it.....time saving with a good spares
inventory ....replace the faulty aspect of equipment and then send through
the system
to component level repairs. Repair was not always attempted and "U/S" tags
were plentiful. Reliability and cost were a decision. I recall when aircraft
mods were
done in Vietnam conflict we just dumped $millions in unusable inventory,
even here. Our (Defence's) vibration and environmental equipment was given
to AWA,
which then charged Defence for the use of it. I found that..a kind-of
peculiar arrangement. Labour costs yes, but use of the gear wasn't confined
to us.

Component level was not always done at Echelon...a level of testing might be
done and a decision made whether to send to the manufacturer but at the card
level
when it was a card....it may more likely have been tagged 'U/S' scrupulously
recorded then binned, later ...perhaps many years later and when security
allowed it and the
conflict was over.....go through the 'disposals auctions'. The equipment
need to ensure the gear met services' specs was too complex and expensive in
some cases.
Reliability warrantied as being certain is primary especially in weaponry
and radar you mentioned demands manufacturer-level accuracy. My recollection
is that
it was not until after 'Korea' thatmodularisation became common...the TRC77
for example in a small way. Until then changing tubes was the field level
repair.




--
Jack


Re: how high would you stack them?

Richard Knoppow
 

If these are all about the same width you could make a rack cabinet with shelves. Open front and back with a little space above each unit for ventilation. Might be that there are shelving items at Home Depot that could be used like side pieces with holes for the clips to hole the shelves. Its worth a look anyway. It would be more stable than just stacking. I know about having more stuff than you have room for.

On 11/2/2018 1:01 PM, Dave Daniel wrote:
For many years I had a stack of the following sitting at one end of my bench. From bottom to top:
HP 8660D signal generator
HP 8556B spec an (both sections)
Tektronix TM-5006A, fully loaded
HP 3456A precision voltmeter
Heathkit GC-1000 clock
These were in a single stack on a very heavy wooden/laminated bench top which sat on two steel 3-drawer pedestals I bought from Global Industries.
I had no support problems and no heat dissipation problems.
I have also had two 7000-series ‘scopes stacked with no problems, but I always worried about knocking the top off because there is no way to have them interlocked.
DaveD
--
Richard Knoppow
dickburk@ix.netcom.com
WB6KBL


Re: No contribution from David Hess since July 18th

Jack
 

Hi Michael....can one buy "pre-shrunk" wire (which actually means before it is shrunk but going along your lines...)to fit into the pre-shrunk heat shrink?

-----Original Message-----
From: Michael A. Terrell
Sent: Saturday, November 3, 2018 5:25 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] No contribution from David Hess since July 18th

I guess that you've never seen the heat shrink connectors for .500, .750 or larger hardline that have to be heated to allow you to slide the cable into? They are pre-shrunk.


Michael A. Terrell


-----Original Message-----
From: Dennis Tillman W7PF <dennis@ridesoft.com>
Sent: Nov 2, 2018 3:05 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] No contribution from David Hess since July 18th

Hi Raymond,

Welcome to the 21st century where our members are spread around the globe and local time is a myth and UTC is the only way to avoid confusion. But that creates its own problems as was evident in this case.

I've been caught by this before specifically when I tried to post my press release announcing "Pre-Shrunk Heat Shrink Tubing" at 12:01AM on April 1st.

Dennis Tillman W7PF




--
Jack


Re: No contribution from David Hess since July 18th

 

On Fri, Nov 2, 2018 at 08:25 PM, Michael A. Terrell wrote:


I guess that you've never seen the heat shrink connectors for .500, .750 or
larger hardline that have to be heated to allow you to slide the cable into?
They are pre-shrunk.
I'm lost!

Raymond


CFL and LED EMI at the bench

Reginald Beardsley
 

FYI I had a huge problem with this. But adding a $3 Chinese EMI filter across the power leads in the light fixture solved it quite nicely. I now keep a bunch them on hand along with various size clamp on ferrite chokes.

https://www.ebay.com/itm/Solder-Lug-Terminal-6A-115-250VAC-Power-Line-EMI-Filter-TS/172173319261

I also use a small loop on a scope probe to track down noise. My HP Z400s emit quite a lot of noise at the PSU fan aperture, so I cover them with a 4" square of 1/8" metal screen (aka hardware cloth). There's also some emission from the fronts, but I've not fixed that yet.

My initial probe loop was about 1/4" and wound on the shanks of drill bits to be a snug fit on the probe tip. Now that I have suppressed a lot of the noise, I plan to make some larger diameter loops.

Naturally, I've taken this to demented levels. All my instruments are now powered via a custom harness made of 1/2" EMT and cut off IEC cords with 5/16" flex steel sheathing. Except for the GPSDO feed, all the instruments are powered though a single switch with the soldering gear on another switched circuit with a hardwired light to make it obvious that the soldering gear is under power..

The motivation for this was the discovery that while the front of my GW Instek MSO was quiet, the other sides emitted a huge amount of SMPS noise which was readily picked up by the power leads for other instruments. I've yet to make measurements of the conducted EMI present on the power line, but will eventually. I also plan to add an isolation transformer and a large EMI filter between the feed and the wall mains outlet. An additional factor was having a dozen instruments stacked on a couple of shelves. I initially used a regular power strip but the fat wad of power cords at the strip became very awkward.

My entire workspace is 7 x 10 ft, 4 x 7 ft for the bench and the rest for my chair, 5 computers, KVM switch, dual monitors and a pair of printers. It's "cozy".


Re: how high would you stack them?

Dave Daniel
 

For many years I had a stack of the following sitting at one end of my bench. From bottom to top:

HP 8660D signal generator
HP 8556B spec an (both sections)
Tektronix TM-5006A, fully loaded
HP 3456A precision voltmeter
Heathkit GC-1000 clock

These were in a single stack on a very heavy wooden/laminated bench top which sat on two steel 3-drawer pedestals I bought from Global Industries.

I had no support problems and no heat dissipation problems.

I have also had two 7000-series ‘scopes stacked with no problems, but I always worried about knocking the top off because there is no way to have them interlocked.

DaveD

Sent from a small flat thingy

On Nov 2, 2018, at 15:12, John Ferguson via Groups.Io <jferg977=aol.com@groups.io> wrote:

I apologize for my simplicity, but I have height but not a lot of bench space. It occurred to be that there might be a limit to haw many scopes/ TM's one might stack so the question is what are you guys doing.

I have a TM 504 with full load of modules on top of bench with a 2445B, next, and then a 2465. I would like to stack another 2445b on top of that. (Don't ask why I have 3 similar scopes - they sort of followed me home [legally])

It looks like putting the TM504 on top would make most sense weight wise, but would make it harder to see screen on bottom scope.

What is most number of these things you'd put atop a very substantial bench?


john




Re: 425 Mil vertical module needed....seeking

Jack
 

Hi Michael....how interesting....no not the PRC, I know the sets you mean though....this was a 'pioneer' set...CW on Tx/Rx and AM on Rx only. RT654A/TRC 77. Still sought after
as a great set....crystal locked but can VFO their current drain on Rx was very small....The US equivalent of Special Air Service regiment (they don't like being called SAS by civies)
used them. I think the term was 'pioneer'...Parts of it were hinged to swing up for service...well so did the p/s of the BC 342 I guess so maybe that's not so modular! I own one so I must
have a closer look..it's been on the shelf for some years, I never even tried it for working but set about trying to collect the associated bits and pieces...not easy here as the gear
in strictly USA. I think there is one of more TRC77 groups amongst the Hams....I recall seeing a very long photographic blurb on them.

I t was a lot easier to carry lightweight spare modules than complete units...but that was really 50's technology emerging as weight diminished with solid state and extra low voltage.
What I see as the forerunner of the PRC 77, the BC1000, was not an easy repair.

Did you find much card failure?

My regards

-----Original Message-----
From: Michael A. Terrell
Sent: Saturday, November 3, 2018 5:17 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

Did you mean the PRC77? if so, both of its predecessors, the PRC10 and the PRC25 were module based radios that were designed to be repaired by swapping in spare, pre-tuned modules. I did Interchangeability testing on the PRC77, along with final test at the Cincinnati Electronics factory.


Michael A. Terrell


-----Original Message-----
From: Jack <goldmort@onthenet.com.au>
Sent: Nov 2, 2018 2:16 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

Hi thanks Harvey....yes that's about it.....time saving with a good spares
inventory ....replace the faulty aspect of equipment and then send through
the system
to component level repairs. Repair was not always attempted and "U/S" tags
were plentiful. Reliability and cost were a decision. I recall when aircraft
mods were
done in Vietnam conflict we just dumped $millions in unusable inventory,
even here. Our (Defence's) vibration and environmental equipment was given
to AWA,
which then charged Defence for the use of it. I found that..a kind-of
peculiar arrangement. Labour costs yes, but use of the gear wasn't confined
to us.

Component level was not always done at Echelon...a level of testing might be
done and a decision made whether to send to the manufacturer but at the card
level
when it was a card....it may more likely have been tagged 'U/S' scrupulously
recorded then binned, later ...perhaps many years later and when security
allowed it and the
conflict was over.....go through the 'disposals auctions'. The equipment
need to ensure the gear met services' specs was too complex and expensive in
some cases.
Reliability warrantied as being certain is primary especially in weaponry
and radar you mentioned demands manufacturer-level accuracy. My recollection
is that
it was not until after 'Korea' thatmodularisation became common...the TRC77
for example in a small way. Until then changing tubes was the field level
repair.




--
Jack


Re: No contribution from David Hess since July 18th

Michael A. Terrell
 

I guess that you've never seen the heat shrink connectors for .500, .750 or larger hardline that have to be heated to allow you to slide the cable into? They are pre-shrunk.


Michael A. Terrell

-----Original Message-----
From: Dennis Tillman W7PF <dennis@ridesoft.com>
Sent: Nov 2, 2018 3:05 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] No contribution from David Hess since July 18th

Hi Raymond,

Welcome to the 21st century where our members are spread around the globe and local time is a myth and UTC is the only way to avoid confusion. But that creates its own problems as was evident in this case.

I've been caught by this before specifically when I tried to post my press release announcing "Pre-Shrunk Heat Shrink Tubing" at 12:01AM on April 1st.

Dennis Tillman W7PF


Send me your suggestions for a TekScopes FAQ

 

When new members join TekScopes this may be the very first time on a forum
or mail reflector.



The thought of asking a question, or replying to a question they can answer,
could be compared to speaking to a room of 7,000 total strangers.



I know we are very helpful to new members, but they don't necessarily know
that.



I think it would help new members if we provided a list of Frequently Asked
Questions (and answers) they could refer to. My goal is to encourage them to
become actively involved rather than passive "lurkers".



So I am asking each of you to think back to when you first joined. What
questions did you have at that time?

What questions do you still have that you would like to know the answers to?



Send your suggestions to me OFF LIST at dennis at ridesoft dot com and I
will organize them into a FAQ and publish it on TekScopes.



Dennis Tillman W7PF


Re: 425 Mil vertical module needed....seeking

Michael A. Terrell
 

Did you mean the PRC77? if so, both of its predecessors, the PRC10 and the PRC25 were module based radios that were designed to be repaired by swapping in spare, pre-tuned modules. I did Interchangeability testing on the PRC77, along with final test at the Cincinnati Electronics factory.


Michael A. Terrell

-----Original Message-----
From: Jack <goldmort@onthenet.com.au>
Sent: Nov 2, 2018 2:16 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking

Hi thanks Harvey....yes that's about it.....time saving with a good spares
inventory ....replace the faulty aspect of equipment and then send through
the system
to component level repairs. Repair was not always attempted and "U/S" tags
were plentiful. Reliability and cost were a decision. I recall when aircraft
mods were
done in Vietnam conflict we just dumped $millions in unusable inventory,
even here. Our (Defence's) vibration and environmental equipment was given
to AWA,
which then charged Defence for the use of it. I found that..a kind-of
peculiar arrangement. Labour costs yes, but use of the gear wasn't confined
to us.

Component level was not always done at Echelon...a level of testing might be
done and a decision made whether to send to the manufacturer but at the card
level
when it was a card....it may more likely have been tagged 'U/S' scrupulously
recorded then binned, later ...perhaps many years later and when security
allowed it and the
conflict was over.....go through the 'disposals auctions'. The equipment
need to ensure the gear met services' specs was too complex and expensive in
some cases.
Reliability warrantied as being certain is primary especially in weaponry
and radar you mentioned demands manufacturer-level accuracy. My recollection
is that
it was not until after 'Korea' thatmodularisation became common...the TRC77
for example in a small way. Until then changing tubes was the field level
repair.


how high would you stack them?

John Ferguson
 

I apologize for my simplicity, but I have height but not a lot of bench space. It occurred to be that there might be a limit to haw many scopes/ TM's one might stack so the question is what are you guys doing.

I have a TM 504 with full load of modules on top of bench with a 2445B, next, and then a 2465.  I would like to stack another 2445b on top of that.  (Don't ask why I have 3 similar scopes - they sort of followed me home [legally])

It looks like putting the TM504 on top would make most sense weight wise, but would make it harder to see screen on bottom scope.

What is most number of these things you'd put atop a very substantial bench?


john


Re: Tek 465 "B" Sweep

 

Raymond Domp Frank
7:52am #152078

No, it is not normal although the area is sensitive to external signals, like hum; you're covering and >grounding a high-impedance part of the vertical input amp, directly after the attenuator block with >attenuation set at 200 mV/div.
Are you sure there's no external source producing something like 50 kHz, if I'm reading the horizontal >settings correctly?

Raymond
You nailed it. There are four CCFLs nearby for theseo ld eyes. Turned them off and;

https://groups.io/g/TekScopes/photo/77251/2?p=Name,,,20,1,0,0

As a side effect I had to learn to set the camera to flash.

Chuck Harris
8:27am #152079

That's a very good point. When I was using CFL illumination
in a desk lamp, at my bench, I used to see a lot of excess noise
signals in hi gain, hi-Z circuitry.
There is also so much hum floating around down here you can forget playing a record on a turntable with a magnetic cartridge. I don't know what to do when I ever have to rip an LP again. I could just about charge money, I can do beta tapes of audio hifi, reel to reel and old 78RPM records. No matter what I do I got hum ion the turntable. Not in tape deck though, go figure. Now I wonder if that 50KHz got into my amp and fried a tweeter...

I guess we are all going to have to remember that about the CCFLs, I wonder if LED lights do the same thing.

Renée
9:50am #152082

check the side of the case there may be "holes" for some of the sensitive adjustments
I see a few all stickered up.

Raymond Domp Frank
10:07am #152083

On Fri, Nov 2, 2018 at 05:50 PM, Renée wrote:

check the side of the case there may be "holes" for some of the sensitive
adjustments. there are on a 475 and the case needs to be installed for those
adjustments.

These holes provide access to e.g. vertical position, attenuator balance and DC gain settings. They >are there as a convenience to allow some adjustments "in the field" without opening the case.
You would be surprised at how much alignment etc. I can do without much equipment.

Chuck Harris
10:12am #152084

I don't remember it that way. The entire 475 can be calibrated
sitting out of its case on the bench. The entire 465 family can
be calibrated sitting out of its case on the bench.
I guess I found that out when I shut those lights off. I'll not soon forget that.

Raymond Domp Frank
10:38am #152088

:On Fri, Nov 2, 2018 at 06:12 PM, Chuck Harris wrote:

The adjustment holes in the case are an indication that some of
the more sensitive circuits are not very stable, and require
occasional touch-up by the operator.

I've never had a need to do any of these adjustments externally, "in the field" so to say, using 464, >465(B), 466 and 475(A) scopes for decades. The "construction" allows unguided poking at least 1.5" >into the 'scope without vision and is asking for involuntary scopeslaughter if a metal screwdriver is >used. Since these 'scopes were used in all kinds of harsh environments, I can imagine that field >adjustment was done in extreme temperature use.
I'll have to sharpen my plastic diddle sticks.

Renée
10:57am #152094

ok, all I recall is I was told ( by the counter tech at tektronix in sunnyvale when my 475 went in for cal >service eons ago... ) the case had to be on for something due to sensitivity/shielding and that is why >the holes were in the case . so that info was false!!!
It seems so.

Thanks for the heads up, now I am going to check the calibration. I don't have anything up to 100MHz though, well actually I do but the fastest rise time I can get out of it is from a buffered 50 ohm output with 10nS. And I have no 50 ohm cable.

We'll see how I get around that :-)

Just now I found out I only have to turn off one of the lights. It's the one with the arm, and of course it has a metal shield and is not grounded. I wonder what would happen if I grounded it...

I'll keep you posted. The other thing is I was surprised at how cheap these things are going on eBay. I might just sell a couple of my lower end scopes and use the money to pay the guy for the "core" of this one. I just fixed the guy almost two grand worth of stuff he's going to sell so he owes me.

Unfortunately I can't do the face thing because due to the topology of my generator the sine is 90 degrees out of phase from the square.

Thanks again for saving me much hassle about the front end.


Re: No contribution from David Hess since July 18th

 

Hi Raymond,

Welcome to the 21st century where our members are spread around the globe and local time is a myth and UTC is the only way to avoid confusion. But that creates its own problems as was evident in this case.

I've been caught by this before specifically when I tried to post my press release announcing "Pre-Shrunk Heat Shrink Tubing" at 12:01AM on April 1st.

Dennis Tillman W7PF

-----Original Message-----
From: Raymond Domp Frank
Sent: Friday, November 02, 2018 11:47 AM
Subject: Re: [TekScopes] No contribution from David Hess since July 18th

On Fri, Nov 2, 2018 at 07:41 PM, Dennis Tillman W7PF wrote:

Dennis,

Your first message said "his last message on this forum is from July
18th."
which is the date I searched. His last post was actually on July 17.
That is why I missed it.
Ha! My date and times are related to UTC and that said July 18th...

Raymond



--
Dennis Tillman W7PF
TekScopes Moderator

24861 - 24880 of 176965