Date   

Re: 2445 LVPS Issues

Tony Fleming
 

Thank you very much! Tony

On Sun, Aug 4, 2019 at 5:47 PM Ancel <protofabtt@gmail.com> wrote:

This project of mine might provide some useful info.
https://hackaday.io/project/163890-tektronix-2465-series-servicing
AB




Re: 2445 LVPS Issues

 

This project of mine might provide some useful info.
https://hackaday.io/project/163890-tektronix-2465-series-servicing
AB


Re: letter series plugins

Morris Odell
 

One of the rarest is the S plugin for observing and measuring diode recovery times. I've actually needed to do this in the recent past and duplicated its function in a customized jig but I'd love to have the real thing. If anyone has one available and doesn't mind shipping down under I'd love to hear from them.

Cheers,

Morris


Re: letter series plugins

Chuck Harris <cfharris@...>
 

Au Contraire? Mais non, certainement pas!

Even Jim Williams was vexed by the 50MHz limit imposed by
his favorites, the 547, and 556....but for opamp, and low
performance switching supply work, they were adequate, as
long as you didn't consider the environmental aspects of
using such a scope (by environmental, I use the traditional
usage, as in: the environment in the lab...).

I grew up as an engineer in the waning days of the 545B, 547
and 585A. I have used all of them for serious electronics work,
as they were what we could get, and I was damn glad to have them
at the time. Still, I simply don't know of anyone that does
serious work with 500 series scopes anymore. The limitations
are too severe. They can't even keep up with a modern USB port.
1MHz switching supplies have spikes that they cannot even come
close to seeing. Just because your scope can't see them, doesn't
mean they won't burn out your transistors and diodes.

Disregarding the low bandwidth, the heat they produce is enough
to eliminate them from serious consideration. I not so fondly
remember my lab in graduate school over taxing the building's air
conditioner with all of the HP and Tektronix gear we needed for
our research. It was intolerable to have the lab get over 110F
in the summer; doors open, huge floor standing fans blowing papers
everywhere. It was so hot that the thermal overload switches in
the scopes were tripped.

Nostalgia is great, especially if you remember only the good
stuff. Thinking fondly of using a scope in the '70s, and using
it for serious electronics work today are not the same thing.

I pull out my 547, 545B, and 585A from time to time to play with,
but when work needs to be done, they are parked in their corral.

My 7854 does most of my heavy lifting, scope wise.

-Chuck Harris

Greg Muir via Groups.Io wrote:

Chuck Harris wrote: “With the exception of the late, great, Jim Williams of Linear Technology fame, big tube scopes, haven't been used for serious electronics work in 30 years.”

Au Contraire. There are still a few Jim Williams types out there who enjoy the use of a stable and reliable product that may have grown gray hair but is still a viable instrument.

Yes, the trend nowadays is to have the fastest, biggest and best of everything in the engineering world but it is not necessary for every application. I am fully aware that the academic institutions must prepare their students to hit the ground running when launched into their professions thereby being able to use state-of-the-art test instruments instead of archaic hardware. And I agree it is nice to be lazy, punch softkeys or click on a mouse to get what you want instantaneously but to come into the lab on a cold winters day with a steaming cup of coffee, hit the switch on that big fire breathing dragon, hear the fan wind up and smell the odor of pure legacy for me is rather pleasing. But if I need speed and easy accuracy I can always reach over and turn on that little solid-state rice box and continue on.

We’ve been obviously witness to the loss of older hardware through the advancements of technology and I have no objections about it happening. But there is that certain amount of tradition in some of us (me – 70 years old, design engineering for 50 of them, raised on tube-type equipment and still going strong) that harks back to those few people who were brave enough to start in their garages endlessly working to serve the engineering profession by manufacturing the best and most technically advanced products of their time.

Some day my 519, 547 and 581 will be relinquished either to a collector or the scrap heap but in the meantime I will still get usefulness out of them.

Greg


Re: letter series plugins

Abc Xyz
 

Chuck,

Nice Sentiment's! I used to have a Couple of old Tube Type Tektronix
Oscilloscopes on the Bench...wish I still had them...lol. Anyway...I am
currently trying to figure out a Horizontal Issue with my Tektronix 465B
Scope.
JR

On Sun, Aug 4, 2019, 10:25 AM Greg Muir via Groups.Io <big_sky_explorer=
yahoo.com@groups.io> wrote:

Chuck Harris wrote: “With the exception of the late, great, Jim Williams
of Linear Technology fame, big tube scopes, haven't been used for serious
electronics work in 30 years.”

Au Contraire. There are still a few Jim Williams types out there who
enjoy the use of a stable and reliable product that may have grown gray
hair but is still a viable instrument.

Yes, the trend nowadays is to have the fastest, biggest and best of
everything in the engineering world but it is not necessary for every
application. I am fully aware that the academic institutions must prepare
their students to hit the ground running when launched into their
professions thereby being able to use state-of-the-art test instruments
instead of archaic hardware. And I agree it is nice to be lazy, punch
softkeys or click on a mouse to get what you want instantaneously but to
come into the lab on a cold winters day with a steaming cup of coffee, hit
the switch on that big fire breathing dragon, hear the fan wind up and
smell the odor of pure legacy for me is rather pleasing. But if I need
speed and easy accuracy I can always reach over and turn on that little
solid-state rice box and continue on.

We’ve been obviously witness to the loss of older hardware through the
advancements of technology and I have no objections about it happening.
But there is that certain amount of tradition in some of us (me – 70 years
old, design engineering for 50 of them, raised on tube-type equipment and
still going strong) that harks back to those few people who were brave
enough to start in their garages endlessly working to serve the engineering
profession by manufacturing the best and most technically advanced products
of their time.

Some day my 519, 547 and 581 will be relinquished either to a collector or
the scrap heap but in the meantime I will still get usefulness out of them.

Greg




Re: letter series plugins

Greg Muir
 

Chuck Harris wrote: “With the exception of the late, great, Jim Williams of Linear Technology fame, big tube scopes, haven't been used for serious electronics work in 30 years.”

Au Contraire. There are still a few Jim Williams types out there who enjoy the use of a stable and reliable product that may have grown gray hair but is still a viable instrument.

Yes, the trend nowadays is to have the fastest, biggest and best of everything in the engineering world but it is not necessary for every application. I am fully aware that the academic institutions must prepare their students to hit the ground running when launched into their professions thereby being able to use state-of-the-art test instruments instead of archaic hardware. And I agree it is nice to be lazy, punch softkeys or click on a mouse to get what you want instantaneously but to come into the lab on a cold winters day with a steaming cup of coffee, hit the switch on that big fire breathing dragon, hear the fan wind up and smell the odor of pure legacy for me is rather pleasing. But if I need speed and easy accuracy I can always reach over and turn on that little solid-state rice box and continue on.

We’ve been obviously witness to the loss of older hardware through the advancements of technology and I have no objections about it happening. But there is that certain amount of tradition in some of us (me – 70 years old, design engineering for 50 of them, raised on tube-type equipment and still going strong) that harks back to those few people who were brave enough to start in their garages endlessly working to serve the engineering profession by manufacturing the best and most technically advanced products of their time.

Some day my 519, 547 and 581 will be relinquished either to a collector or the scrap heap but in the meantime I will still get usefulness out of them.

Greg


Re: Tektronix 492BP Spectrum Analyser Repair: Only fundamental 0-1.8GHz band works

John Miles
 

There may not be anything really wrong with it, depending on whether the stored peaking constants are valid. Do a search in the manual for the term 'REPEAK', and it should give you an idea what to try.

If your internal lithium or silver-oxide battery is dead, the instrument may not be capable of retaining the peaking constants. So you'd need to either replace the battery or leave it in manual-peaking mode in that case. (No internal calibration data is saved in the battery-backed RAM, but the front-panel calibration and peaking information is.)

And yes, you can conclude that the preselector and its associated RF plumbing itself are most likely OK, if the knob works. It's possible that the knob is active by default at power-up time -- not 100% sure about that -- and if so, your stored constants may be OK. Someone may have just left the knob at an inappropriate setting for the frequency you were looking at.

-- john, KE5FX

Thanks for your help.

I tried what you suggested, and it works! So does that mean the preselector
path is OK and the fault is with the YIG preselector sweep/sync circuitry?


Re: 2445 LVPS Issues

Chuck Harris <cfharris@...>
 

Two different black covers. The one over the mains input
has a couple of screws through the back panel, and then it
lifts off and out.

-Chuck Harris


n4buq wrote:

I was under the impression that the black cover would not allow the boards to be removed beforehand but if that's the case, then okay. I see to recall removing that before on perhaps a different scope but just didn't see how to get it out this time.

I'll check the ESR on the big caps as well. Good to know that those may not need replacing. As I said, I'm pretty sure I see bulging on several of the smaller caps on the regulator(?) board so will plan to replace all of them.

Thanks,
Barry - N4BUQ


Re: 2445 LVPS Issues

n4buq
 

And there, on page 6-25, is the complete process spelled out very neatly. Just didn't expect that.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "n4buq" <n4buq@knology.net>
To: TekScopes@groups.io
Sent: Saturday, August 3, 2019 9:03:44 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

I didn't realize the SM would go into detail on board removal. I will read
up on it there.

Thanks for the tip on the incorrect silkscreen too.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Tom Gardner" <tggzzz@gmail.com>
To: TekScopes@groups.io
Sent: Saturday, August 3, 2019 7:10:03 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

The service manual is quite specific on how to remove the various boards.
It
isn't difficult, if follow instructions.

The manual is available at the usual places, e.g. tekwiki.

Be aware that on some of the 24x5* series the manual and silk screen show
two
caps swapped. So when recapping, remove and replace a single capacitor
before
moving on to the next; don't remove them all and then start replacing them.


On 04/08/19 00:13, n4buq wrote:
I was using my 2445 today when I heard a strange sort of thump noise
coming
from inside the scope after which I started smelling a burning odor. I
had a few pieces of gear powered up at the time but quickly could tell
the
smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is coming
from
the LVPS board(s) but am a bit stumped at how to get those two boards
out.
I'm pretty sure the top ribbon cable needs to come off but don't quite
see how to get the large plastic cover off of the area where the main
filter caps are.

Looking at some of the smaller caps, they appear to be leaning due to
(I'm
guessing) bulging at the circuit board end but not sure exactly what
overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those boards?
If not, could someone provide a couple of hints to get me started?

Thanks,
Barry - N4BUQ






Re: 2445 LVPS Issues

n4buq
 

I was under the impression that the black cover would not allow the boards to be removed beforehand but if that's the case, then okay. I see to recall removing that before on perhaps a different scope but just didn't see how to get it out this time.

I'll check the ESR on the big caps as well. Good to know that those may not need replacing. As I said, I'm pretty sure I see bulging on several of the smaller caps on the regulator(?) board so will plan to replace all of them.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "tom jobe" <tomjobe@gmail.com>
To: TekScopes@groups.io
Sent: Saturday, August 3, 2019 7:29:21 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

If you are talking about the black cover over the two largest
capacitors, there is a prong that goes down in the middle between the
two bumps, the prong has a hook on one side of it that latches the cover
in place. You deflect the prong to the side a little bit and the cover
comes off in your hand. Maybe wait until you have the power supply out
on the bench before trying to remove the black cover?
Those two large capacitors never seem to give any trouble in a 24x5 but
have a look anyway and check the ESR if it is easy for you to do.
Replace all of the smaller caps regardless of how they look or the ESR
checks out. I see you have been warned about the schematic errors on two
of the capacitors, don't miss this problem.
There is excellent help available here on Tekscopes for the 24x5 scope
family.


On 8/3/2019 4:13 PM, n4buq wrote:
I was using my 2445 today when I heard a strange sort of thump noise coming
from inside the scope after which I startettd smelling a burning odor. I
had a few pieces of gear powered up at the time but quickly could tell the
smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is coming from
the LVPS board(s) but am a bit stumped at how to get those two boards out.
I'm pretty sure the top ribbon cable needs to come off but don't quite
see how to get the large plastic cover off of the area where the main
filter caps are.

Looking at some of the smaller caps, they appear to be leaning due to (I'm
guessing) bulging at the circuit board end but not sure exactly what
overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those boards?
If not, could someone provide a couple of hints to get me started?

Thanks,
Barry - N4BUQ







Re: 2445 LVPS Issues

n4buq
 

I didn't realize the SM would go into detail on board removal. I will read up on it there.

Thanks for the tip on the incorrect silkscreen too.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Tom Gardner" <tggzzz@gmail.com>
To: TekScopes@groups.io
Sent: Saturday, August 3, 2019 7:10:03 PM
Subject: Re: [TekScopes] 2445 LVPS Issues

The service manual is quite specific on how to remove the various boards. It
isn't difficult, if follow instructions.

The manual is available at the usual places, e.g. tekwiki.

Be aware that on some of the 24x5* series the manual and silk screen show two
caps swapped. So when recapping, remove and replace a single capacitor before
moving on to the next; don't remove them all and then start replacing them.


On 04/08/19 00:13, n4buq wrote:
I was using my 2445 today when I heard a strange sort of thump noise coming
from inside the scope after which I started smelling a burning odor. I
had a few pieces of gear powered up at the time but quickly could tell the
smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is coming from
the LVPS board(s) but am a bit stumped at how to get those two boards out.
I'm pretty sure the top ribbon cable needs to come off but don't quite
see how to get the large plastic cover off of the area where the main
filter caps are.

Looking at some of the smaller caps, they appear to be leaning due to (I'm
guessing) bulging at the circuit board end but not sure exactly what
overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those boards?
If not, could someone provide a couple of hints to get me started?

Thanks,
Barry - N4BUQ




Re: 2445 LVPS Issues

tom jobe <tomjobe@...>
 

If you are talking about the black cover over the two largest capacitors, there is a prong that goes down in the middle between the two bumps, the prong has a hook on one side of it that latches the cover in place. You deflect the prong to the side a little bit and the cover comes off in your hand. Maybe wait until you have the power supply out on the bench before trying to remove the black cover?
Those two large capacitors never seem to give any trouble in a 24x5 but have a look anyway and check the ESR if it is easy for you to do. Replace all of the smaller caps regardless of how they look or the ESR checks out. I see you have been warned about the schematic errors on two of the capacitors, don't miss this problem.
There is excellent help available here on Tekscopes for the 24x5 scope family.

On 8/3/2019 4:13 PM, n4buq wrote:
I was using my 2445 today when I heard a strange sort of thump noise coming from inside the scope after which I startettd smelling a burning odor. I had a few pieces of gear powered up at the time but quickly could tell the smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is coming from the LVPS board(s) but am a bit stumped at how to get those two boards out. I'm pretty sure the top ribbon cable needs to come off but don't quite see how to get the large plastic cover off of the area where the main filter caps are.

Looking at some of the smaller caps, they appear to be leaning due to (I'm guessing) bulging at the circuit board end but not sure exactly what overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those boards? If not, could someone provide a couple of hints to get me started?

Thanks,
Barry - N4BUQ



Re: 2445 LVPS Issues

Tom Gardner
 

The service manual is quite specific on how to remove the various boards. It isn't difficult, if follow instructions.

The manual is available at the usual places, e.g. tekwiki.

Be aware that on some of the 24x5* series the manual and silk screen show two caps swapped. So when recapping, remove and replace a single capacitor before moving on to the next; don't remove them all and then start replacing them.

On 04/08/19 00:13, n4buq wrote:
I was using my 2445 today when I heard a strange sort of thump noise coming from inside the scope after which I started smelling a burning odor. I had a few pieces of gear powered up at the time but quickly could tell the smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is coming from the LVPS board(s) but am a bit stumped at how to get those two boards out. I'm pretty sure the top ribbon cable needs to come off but don't quite see how to get the large plastic cover off of the area where the main filter caps are.

Looking at some of the smaller caps, they appear to be leaning due to (I'm guessing) bulging at the circuit board end but not sure exactly what overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those boards? If not, could someone provide a couple of hints to get me started?

Thanks,
Barry - N4BUQ


2445 LVPS Issues

n4buq
 

I was using my 2445 today when I heard a strange sort of thump noise coming from inside the scope after which I started smelling a burning odor. I had a few pieces of gear powered up at the time but quickly could tell the smell was coming from the 2445.

I took off the case and top cover and pretty sure the smell is coming from the LVPS board(s) but am a bit stumped at how to get those two boards out. I'm pretty sure the top ribbon cable needs to come off but don't quite see how to get the large plastic cover off of the area where the main filter caps are.

Looking at some of the smaller caps, they appear to be leaning due to (I'm guessing) bulging at the circuit board end but not sure exactly what overheated (or, possibly, made that thumping noise).

Are there instructions somewhere that outline how to remove those boards? If not, could someone provide a couple of hints to get me started?

Thanks,
Barry - N4BUQ


Re: letter series plugins

David Holland
 

On Sat, Aug 3, 2019 at 9:42 AM snapdiode via Groups.Io
<snapdiode=yahoo.com@groups.io> wrote:

I guess the answer is that everyone who got the bug to collect these things has done so, and dried up the supply.
I suppose this means the demand is also gone, I can't picture anyone wanting to buy a 500 series setup today to play around with Arduinos...
I like my 547, as a display piece.
I dunno, I like *using* my 560 series equipment, and am working on
finishing my collection. I guess I should have started earlier...
;-)

Obligatory: Any have a 3L10, 3A2, 3B2, or 3B5 they're looking to
unload? :-) I think those are the remaining ones I'm missing I
can see a use for, a 3C66, not so much...

David


Re: letter series plugins

Chuck Harris <cfharris@...>
 

With the exception of the late, great, Jim Williams of Linear
Technology fame, big tube scopes, haven't been used for serious
electronics work in 30 years.

Model T Fords haven't been used for serious transportation duties
in even longer, and yet they are still available; if you have the
necessary jingle in your pocket you too can own one.

Like a Model T Ford, owning a 500 series scope is more about
esthetics, than about practical use.

Ply me with money, and you can have all of mine.

-Chuck Harris

snapdiode via Groups.Io wrote:

I guess the answer is that everyone who got the bug to collect these things has done so, and dried up the supply.
I suppose this means the demand is also gone, I can't picture anyone wanting to buy a 500 series setup today to play around with Arduinos...
I like my 547, as a display piece.




Re: letter series plugins

Dave Daniel
 

I’m still looking for a TU-7.

DaveD

Sent from a small flat thingy

On Aug 3, 2019, at 09:41, snapdiode via Groups.Io <snapdiode=yahoo.com@groups.io> wrote:

I guess the answer is that everyone who got the bug to collect these things has done so, and dried up the supply.
I suppose this means the demand is also gone, I can't picture anyone wanting to buy a 500 series setup today to play around with Arduinos...
I like my 547, as a display piece.



Re: letter series plugins

snapdiode
 

I guess the answer is that everyone who got the bug to collect these things has done so, and dried up the supply.
I suppose this means the demand is also gone, I can't picture anyone wanting to buy a 500 series setup today to play around with Arduinos...
I like my 547, as a display piece.


Re: Tektronix 492BP Spectrum Analyser Repair: Only fundamental 0-1.8GHz band works

adil malik
 

Thanks for your help.

I tried what you suggested, and it works! So does that mean the preselector path is OK and the fault is with the YIG preselector sweep/sync circuitry?


Re: Tektronix 492BP Spectrum Analyser Repair: Only fundamental 0-1.8GHz band works

adil malik
 

Yes, what I meant was I think the path is dead completely.

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