Date   

Re: 465 Display Help Needed - another thought

ashtonb@...
 

--- In TekScopes@y..., Kurt Graber <kurtg@s...> wrote:


billw101@a... wrote:

Hello, I have been pulling problems out of a 465 that I recently
acquired. The last remaining problem is the inability to get a
sharp
focus on the trace with any combination of intensity, focus or
astigmatism. I have checked everything in the CRT circuits with
the
exception of the high voltage, crt bias and cathode bias, until I
get
the use of an HV probe. Can anyone tell me if I am looking in the
right area or suggest any common failure modes? The low voltage
supplies all check good and noise free. Thanks for any help.
...........................................



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A common problem or failure is the opening of the voltage divider
circuit
that the focus and astig tap into.
I am unfamilier with your particular scope but the chances are good
that one
of the resistors has opened up. I have seen many cases !!! you
don't
need a
HV probe , just take your meter and ohm them out. They will not
appear burned
but they have a tendancy to open up due to the high
voltage.......this will
cause an unsharp trace and many cases no trace at all (just a
haze)...Good
Luck
Another point: the 46x, 47x series just wasn't as sharp as the tube
scopes! or even and especially - the 454, 454A. Some engrs. think
the 454A best 150 MHz scope ever (2mV/DIV, all the delay triggering)
or sometimes ~ 200 MHz if all went well on that assembly..

I can see the clear difference bewtween say, a 475A and the 454As -
tiny wiggles just visible on 54-A disappear into the thick trace of
475 (or 465).

Just in case you're trying to do better than it Can!


Ashton


Re: *Cheap* Equipment sources

ashtonb@...
 

--- In TekScopes@y..., Michael Dunn <mdunn@c...> wrote:
Just a little poll of sorts: I'm wondering where we all find
old
equipment -- at least the stuff we get for real cheap!

I and a friend on this list have found pretty much all our
stuff
at "garage sales" held at a local university. We're talking REAL
cheap. C$10-$20 (U$7-14) for anything from a 502A to a 549 or 556!
$5 for a plug-in. Usually in very good condition. How about you?
Hello Michael, and thanks for helping me get past the sign-on glitch.
As you can see, posting now works too [I think - we'll see].

I started accumulating Teks (beyond a couple for use) ~ 3 years ago
pre- eBay for me.. A fireman in LA had an ad in Nuts&Volts.. ended
up sending along an initial 10ish scopes (mostly 453s) and a year
later, more things.

Truck rate and such seems about only way to handle high ship'g cost,
but that means ~ 300ish # to come out reasonably. This may not be
true in '01 (?).

Now I have to read some back posts. I've mainly used Tek scopes
forever - only lately repair / calibrate, but without the tricks that
experience teaches (might tell about the 2430 with no warning about
needing an extra fan - except buried in the Service Manual. Ugh.
All those labels about imploding CRTs but - not one saying "cool it -
Now!")

Ashton Brown
Sonoma county, No. Calif.


Re: *Cheap* Equipment sources

Jams & Kandy Nunn <jnunn@...>
 

I started my collection with a 535a that I purchased at a garage sale for $1. The scope came with CA plug-in and a set of probes. I always admired the Tek scopes from the 60's and thought that it would be fun to fix it or take it apart. I ended up doing both and spending a lot more than a buck to get it working. My other "sea story" is a 545a that I purchased from a TV station last year. The scope was calibrated! has the "old" style cart, 4 probes, a CA and a M plug-in and a 1L5 (not working) all the original manuals and I found the original purchase order in the operators manual compartment, total cost was $60.

Most of what I purchase I find on E-bay or the TRW swap meet (I live in LA).

Jim Nunn


Re: 465 Display Help Needed

Kurt Graber <kurtg@...>
 

billw101@aol.com wrote:

Hello, I have been pulling problems out of a 465 that I recently
acquired. The last remaining problem is the inability to get a sharp
focus on the trace with any combination of intensity, focus or
astigmatism. I have checked everything in the CRT circuits with the
exception of the high voltage, crt bias and cathode bias, until I get
the use of an HV probe. Can anyone tell me if I am looking in the
right area or suggest any common failure modes? The low voltage
supplies all check good and noise free. Thanks for any help.

To unsubscribe from this group, send an email to:
TekScopes-unsubscribe@egroups.com



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A common problem or failure is the opening of the voltage divider circuit
that the focus and astig tap into.
I am unfamilier with your particular scope but the chances are good that one
of the resistors has opened up. I have seen many cases !!! you don't need a
HV probe , just take your meter and ohm them out. They will not appear burned
but they have a tendancy to open up due to the high voltage.......this will
cause an unsharp trace and many cases no trace at all (just a haze)...Good
Luck


Re: *Cheap* Equipment sources

Michael <mdd@...>
 

I and a friend on this list have found pretty much all our stuff
at "garage sales" held at a local university. We're talking REAL
cheap. C$10-$20 (U$7-14) for anything from a 502A to a 549 or 556!
$5 for a plug-in. Usually in very good condition. How about you?
Gee, half your luck! I've never seen any Tek stuff at garage sales (not that
I go to many), and paid A$600 (around US$1200) for my (as new) 7603; but I
was given a TM503 with a DM501A (faulty) and three plug-in kits in exchange
for a satellite TV receiver. Meanwhile I have (mostly) fixed the DM501 and
keep looking... :)

Kind regards,
:)
Michael


Re: *Cheap* Equipment sources

ronald h. driggers <rdriggers@...>
 

I paid 25 for the 545a, most of the plugins cost 15 to 20, bought one on
ebay as well as some of my manuals, some of the stuff is in a salvage yard,
near by, but they run 25 to 45 dollars depending on the size and weight,
they look at the scrap value, bought the ca and the 130 lc meter this
weeking for 20 dollars for the two, more than i want to spend but i am in a
bad area for old tek stuff. I have found others but can not pay shipping.
You seem to buy much cheaper than i can, the 556 i got was 20.00 dolllars,
may not be an easy repair though. Since this is a hobby cheaper would be
MUCH better for me. I have payed more for manuals than equipment.

----- Original Message -----
From: Michael Dunn <mdunn@cantares.on.ca>
To: <TekScopes@yahoogroups.com>
Sent: Monday, April 23, 2001 10:17 AM
Subject: [TekScopes] *Cheap* Equipment sources


Just a little poll of sorts: I'm wondering where we all find old
equipment -- at least the stuff we get for real cheap!

I and a friend on this list have found pretty much all our stuff
at "garage sales" held at a local university. We're talking REAL
cheap. C$10-$20 (U$7-14) for anything from a 502A to a 549 or 556!
$5 for a plug-in. Usually in very good condition. How about you?


-----------------------------------------------------------------
Michael Dunn | Surround Sound Decoder & Stereo Enhancer
Cantares | Self-Amplified Speakers, Test Equipment
74 George St. | Ambisonic Surround Sound CDs and Recording
Waterloo, Ont. | (519) 744-9395 (fax: 744-7129)
N2J 1K7 | mdunn@cantares.on.ca
Canada | http://www.cantares.on.ca/
-----------------------------------------------------------------

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*Cheap* Equipment sources

Michael Dunn <mdunn@...>
 

Just a little poll of sorts: I'm wondering where we all find old equipment -- at least the stuff we get for real cheap!

I and a friend on this list have found pretty much all our stuff at "garage sales" held at a local university. We're talking REAL cheap. C$10-$20 (U$7-14) for anything from a 502A to a 549 or 556! $5 for a plug-in. Usually in very good condition. How about you?


-----------------------------------------------------------------
Michael Dunn | Surround Sound Decoder & Stereo Enhancer
Cantares | Self-Amplified Speakers, Test Equipment
74 George St. | Ambisonic Surround Sound CDs and Recording
Waterloo, Ont. | (519) 744-9395 (fax: 744-7129)
N2J 1K7 | mdunn@cantares.on.ca
Canada | http://www.cantares.on.ca/
-----------------------------------------------------------------


465 Display Help Needed

Bill Wollam
 

Hello, I have been pulling problems out of a 465 that I recently
acquired. The last remaining problem is the inability to get a sharp
focus on the trace with any combination of intensity, focus or
astigmatism. I have checked everything in the CRT circuits with the
exception of the high voltage, crt bias and cathode bias, until I get
the use of an HV probe. Can anyone tell me if I am looking in the
right area or suggest any common failure modes? The low voltage
supplies all check good and noise free. Thanks for any help.


Re: Tek 7104 readout problem

L. Mark Pilant <n1vqw@...>
 

I haven't ever looked at a 7100 scope, but I did have a 7904
with a very dim readout. If you turned the trace intensity all
the way down and dimmed the lights, you could make out the
readout characters.

In my case, it turned out to be the Z-blanking board was way
out of calibration. I went through the calibration procedure
until I got the the blanking board. When I did the board, I
suddenly had the readout. (And everything still worked as well :-)

Going through the rest of the calibration procedures showed the
rest of the 'scope wasn't that far out of spec.

I hope this helps.

- Mark


Tek 7104 readout problem

dd@...
 

I have a 7104 and now a 7103 that have the same readout problem. The
readout is not visible unless the intensity knob is turned CW to the
"pulsed" position and then pushed against the stop.

On the 7104, I found that the TP1925 voltage was at -6.3V in the full CW
position, and I could make the readout go on by pulling it to about -11V,
so I tacked in a couple of resistors to change the range of the readout
intensity control. (Note, another problem this scope has is that the A/B
intensity knob indicator lamps don't activate properly, but I have no idea
if that's related.)

I wasn't totally happy with the above hack, and now that I have a 7103
with the exact same problem, I would really like to find the underlying
cause... has anyone seen/fixed this?

Thanks...


Re: Tek 7904 Display Problem

Mark Gurries <gurriesm@...>
 

BTW Hi Mark Gurries glad to see you on the list.
Hi Don.

Been watching the list for a while. It was from one of your email on the
DCC list that I learned about this list. Anyway...

I told Jim Williams here at Linear Tech about this list. (My Lab bench
is next to his.) But he is not one to use PC's. That Jim for ya. For
those who are not familiar with Jim, he is one of out treasured assets at
the company. Hi writes many application notes for our IC and tackling
problems and parts that cause most of us to glaze over our eyes in terms
of the accuracy or noise level requirements. Things like how do you
verify all 24 bits of a 24 bit DAC!

The trick around here to getting a Tek scope fixed and checked out by Jim
Williams is to get an old 500 or 400 series scope in the lab. Tell Jim
about it, and the fact that it does not work annoys Jim to no end.
Before you know it, he is digging into the scope and fixing everything.
Not that we cannot fix out own scopes mind you, but, Jim does a faster
and better job than anyone I know. It fun to watch him and of course you
learn along the way the history and debug tricks.

We have about every make of Tek scope at the company labs. We have lots
of 547's working in parallel with the latest Tek Scopes. We just got
around to setting up an old 556 dual beam on another engineers lab bench.
454's are another favorite. A few of the guys have 7K stuff like yours.
One of my employees has every 7K plug in made including some test
adapters if I recall correctly. It amazing to see the latest scopes
setup right next to an old classic. The biggest reason we like the old
400 and 500 series scopes is the very fine trace and excellent noise
floor. When Jim sets up his 556 with two 1A4 plugins showing 8 traces
that are all beautifully detailed (4 of the traces are on a different
time base to boot) published in a App note, we sometimes get letters and
calls about the scope photo alone! How did you do that?

We think that our lab is one of the biggest consumers of electricity in
Silicon Valley with all these Tube Tek scopes on and possibly the source
of all the blackouts here in California. We already went though one air
conditioner! ;-0


Best Regards,

Mark Gurries
gurriesm@macconnect.com

---------------------------------------------------------
Promotor of the DCC Standard for Model trains.
Model Railroad Club and NMRA DCC presentations are at:
http://www.falken.net/dave/svl
--------------------------------------------------------
Audio Enthusiast (Love SAE equipment)
http://members.ebay.com/aboutme/gurriesm/
http://www.wardsweb.org/audio/index_audio.html
----------------------------------------------------------


Re: 127

Stan or Patricia Griffiths <w7ni@...>
 

Hi Morris,

Well, Tek made TWO different silicon mod kits for the 127, depending upon the
serial number of your instrument. For Serial Number 100-357, it is 040-0217-00
and for Serial Number 358-1409, it is 040-0282-00. There are about 8 pages in
each instruction set. So, if you tell me your Serial Number, I will get a copy
of the appropriate kit instructions for you. It will cost you about $2 plus
postage.

Stan
w7ni@easystreet.com

Stan or Patricia Griffiths wrote:

Hi Morris,

I am sure Tek made a silicon replacement kit for those seleniums. I am sure
I have a copy of it on microfiche. I will check that out at my next free
moment and see about taking my microfiche to the local library and making you
a hard copy of the mod instructions for you. I promise to keep the price of
my labor within reason . . .

Don't let me forget this . . . at age 62, things sometimes fall in the
cracks.

Stan
w7ni@easystreet.com

morriso2002@yahoo.com.au wrote:

I have picked up a 127 preamp power supply that is used to power a
couple of 1- or letter plugins for use as instrument amplifiers. It's
quite a boatanchor and seems to work OK but I want to replace the
selenium rectifiers in it with silicon for safety reasons.

There are 5 rectifiers in there. To save me a bit of measurement work,
does anybody have any info on function/ratings of the rectifiers or
whether Tek issued a bulletin on their replacement?

Morris

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100!!!

Michael Dunn <mdunn@...>
 

Congratulations TekGroup! We've hit 100 members!


-----------------------------------------------------------------
Michael Dunn | Surround Sound Decoder & Stereo Enhancer
Cantares | Self-Amplified Speakers, Test Equipment
74 George St. | Ambisonic Surround Sound CDs and Recording
Waterloo, Ont. | (519) 744-9395 (fax: 744-7129)
N2J 1K7 | mdunn@cantares.on.ca
Canada | http://www.cantares.on.ca/
-----------------------------------------------------------------


Re: Manual Sources

Stan or Patricia Griffiths <w7ni@...>
 

dhuster@pb.k12.mo.us wrote:

Hi, Stan,

I was the one (Dean) who mentioned the manuals on 'fiche. I suppose
that I'm only assuming that they're doing that since they were so hot
to get all of us Service Center technicians to quit using paper
manuals and rely solely upon 'fiche for our documentation. It must
have been the same folks who did the mechanical design on the 434
that came up with that idea. In 1982, you could order the manual of
Tek's oldest scopes on 'fiche. I just assumed .....

It also makes me sick. I may have told you this story already.
Since I was the sole tech at the OKC Service Center, I got all
the 'fiche updates each week and dutifully made them. But I never
threw away the old 'fiche as it was replaced with the new. When I
left Tek, I had a nearly complete set of 'fiche from the oldest
instrument to the newest, through all the T&M, television, medical,
IDG (computer) and old catalogs and sales literature. I literally
gave it all away to a friend in Dallas who owned a cal lab there (a
lab that was sucking away an alarming amount of business from the
Dallas Service Center -- I'll have to tell you about Dale sometime)
in trade for a few pieces of older hp test equipment. I'll bet that
I could sell that 18" stack of 'fiche on eBay for an easy 4-figures
today, especially if Tek no longer produces it. I assume that
they've converted it all to PDF?

Dean

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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Well, Tek USED to do exactly as you described . . . make all the old data
available on microfiche. I think they quit doing it a couple of years ago.
I am not familiar with the term "PDF" but I assume it is some form of
computer readable pages that would put the old microfiche images on your
computer screen. I am not aware that Tek has bothered to do that with any
but current instruments. I think all of the old data is simply "gone" as far
as Tek is concerned. And yes, that pile of old microfiche is probably worth
all of 4 figures today. Very sad . . .

Stan
w7ni@easystreet.com


Re: 8608

Michael Dunn <mdunn@...>
 

At 12:24 PM +0000 2001/4/18, rdriggers@hitter.net wrote:
Hello, since you have a 556 you may be the one to know, i just picked
up for cheap a 556 that looked good, but when i got it home it looks
as if a rodent has eaten a lot of the wires and insulation on the
inside. Is this scope worth the effort to repair or maybe i should
use it for parts. I have a manual and all the parts are there, the
case looks good and is straight.

Well, if you have the room, it's quite the scope, don't you think? ;-) On the other hand, I would buy the manual from you!

Michael


Re: Manual Sources

dhuster@...
 

Hi, Stan,

I was the one (Dean) who mentioned the manuals on 'fiche. I suppose
that I'm only assuming that they're doing that since they were so hot
to get all of us Service Center technicians to quit using paper
manuals and rely solely upon 'fiche for our documentation. It must
have been the same folks who did the mechanical design on the 434
that came up with that idea. In 1982, you could order the manual of
Tek's oldest scopes on 'fiche. I just assumed .....

It also makes me sick. I may have told you this story already.
Since I was the sole tech at the OKC Service Center, I got all
the 'fiche updates each week and dutifully made them. But I never
threw away the old 'fiche as it was replaced with the new. When I
left Tek, I had a nearly complete set of 'fiche from the oldest
instrument to the newest, through all the T&M, television, medical,
IDG (computer) and old catalogs and sales literature. I literally
gave it all away to a friend in Dallas who owned a cal lab there (a
lab that was sucking away an alarming amount of business from the
Dallas Service Center -- I'll have to tell you about Dale sometime)
in trade for a few pieces of older hp test equipment. I'll bet that
I could sell that 18" stack of 'fiche on eBay for an easy 4-figures
today, especially if Tek no longer produces it. I assume that
they've converted it all to PDF?

Dean


Re: 8608

rdriggers@...
 

Hello, since you have a 556 you may be the one to know, i just picked
up for cheap a 556 that looked good, but when i got it home it looks
as if a rodent has eaten a lot of the wires and insulation on the
inside. Is this scope worth the effort to repair or maybe i should
use it for parts. I have a manual and all the parts are there, the
case looks good and is straight. I have a 545a and a 453 that i use
but i have not used a 556.




--- In TekScopes@y..., Michael Dunn <mdunn@c...> wrote:
Yoohoo. I got a pair of NOS, Tek-boxed 8608 tubes for the
vertical of my 556! They work great. Has anyone else had an 8608
fail on them. My bad one had a grid short. I noticed it because
the
vertical position knob acted like a light dimmer, making the tube
glow incandescent white depending on the setting!!!

Michael

-----------------------------------------------------------------
Michael Dunn | Surround Sound Decoder & Stereo Enhancer
Cantares | Self-Amplified Speakers, Test Equipment
74 George St. | Ambisonic Surround Sound CDs and Recording
Waterloo, Ont. | (519) 744-9395 (fax: 744-7129)
N2J 1K7 | mdunn@c...
Canada | http://www.cantares.on.ca/
-----------------------------------------------------------------


Re: 127

Stan or Patricia Griffiths <w7ni@...>
 

Hi Morris,

I am sure Tek made a silicon replacement kit for those seleniums. I am sure
I have a copy of it on microfiche. I will check that out at my next free
moment and see about taking my microfiche to the local library and making you
a hard copy of the mod instructions for you. I promise to keep the price of
my labor within reason . . .

Don't let me forget this . . . at age 62, things sometimes fall in the
cracks.

Stan
w7ni@easystreet.com

morriso2002@yahoo.com.au wrote:

I have picked up a 127 preamp power supply that is used to power a
couple of 1- or letter plugins for use as instrument amplifiers. It's
quite a boatanchor and seems to work OK but I want to replace the
selenium rectifiers in it with silicon for safety reasons.

There are 5 rectifiers in there. To save me a bit of measurement work,
does anybody have any info on function/ratings of the rectifiers or
whether Tek issued a bulletin on their replacement?

Morris

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127

morriso2002@...
 

I have picked up a 127 preamp power supply that is used to power a
couple of 1- or letter plugins for use as instrument amplifiers. It's
quite a boatanchor and seems to work OK but I want to replace the
selenium rectifiers in it with silicon for safety reasons.

There are 5 rectifiers in there. To save me a bit of measurement work,
does anybody have any info on function/ratings of the rectifiers or
whether Tek issued a bulletin on their replacement?

Morris


Re: Manual Sources

Stan or Patricia Griffiths <w7ni@...>
 

Hi Doug,

Are you really sure Tek still offers older manuals on microfiche? Last time
I checked I thought they had discontinued that, too.

Stan
w7ni@easystreet.com

dhuster@pb.k12.mo.us wrote:

Hi, Doug,

Check out the "Q&A" column in the February 2001 issue of "Poptronics"
magazine (formerly "Popular Electronics" and "Electronics Now"
magazines) for a list of manual sources. Also check out my post at
http://www.nostalgiaair.org/nostalgiaair/messageboard/newforum/840.htm
for manual source listings. Tek doesn't offer any manuals in paper
for older instruments, only on microfiche, but it's cheaper anyway.
Used 'fiche readers are cheap or many libraries have reader/printers
available.

Dean Huster
Contributing Editor, "Q&A"
"Poptronics Magazine"
q&a@gernsback.con
http://www.poptronics.com/forums/index.html

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