Date   
Re: Capacitor testing

james_55@...
 

On Sat, Apr 4, 2020 at 09:21 PM, Roy Morgan wrote:


Long and expert experience with Collins amateur equipment tells us to limit
the reforming current to FIVE MILLAMPS.

Take your time. Monitor cap voltage and reforming current. Be patient.

I have a Heath variable bench supply - DC variable from about 0 to 300 volts
or so, I use a 10k or 5K, 5 or 10 watt resistor in series. The current meter
on the supply lets me keep reforming current low, and a separate voltmeter
shows me the caps progress.

Do not follow the procedure given in the MIL-HANDBOOK on reforming
electrolytics. There is real danger of disaster doing that (Parallel many
caps, reform them with a light bulb series with a DC supply, limiting current
to the total for all caps.)

Roy


On Apr 4, 2020, at 5:14 AM, james_55@... wrote:

Hi and thanks for the sugestion.

Any recommendation as to the resistor value?

1k 100k?

Roy Morgan
K1LKY since 1958
k1lky68@...



Nice one. Thank You

open hardware sampler oscilloscope development video by Ted Yapo mentions Tek many times.

John Griessen
 

https://www.youtube.com/watch?v=99u53V7uDFY

Mentions S-4 sampler, 11801 with SD24's along the way

BOM cost of system he has, (not including various DC supplies), is < $100 for about 7GHz bandwidth.

Re: A sick 7603 can it be restored?

Eric
 

I was able to pull apart the power supply and just hit the order button on the parts. Ill be sanity checking the parts but some of the filters are toast. I have some high quality replacements on the way so hopefully this supply will be good for the rest of my time. Ill keep everyone posted as to the progress thanks for the help so far everyone.

Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of bobh@...
Sent: Friday, April 3, 2020 7:23 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] A sick 7603 can it be restored?

If you have a bad filter cap, with high ESR, one thing you can do to prove to yourself that you found the real issue is to parallel the questionable cap with a good one. If the unreg supply and the other supplies come back you found the problem. This was suggested to me when I was in your place and it worked.

Bob.

On 4/3/2020 6:35 AM, Eric wrote:
Well before I do anything else I have to address the capacitor issue.
Got the scope hooked up to the -50V rail and there is 260mV pk-pk of
ripple . It is a nice clean saw tooth generator at the moment. Glad I
had it on the current limited supply. The reading was on the -50V test
point on the regulator board. I guess I am tearing down the power
supply. Spec for the Ripple is only 5mV pk-pk

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of
bobh@...
Sent: Friday, April 3, 2020 9:04 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] A sick 7603 can it be restored?

The -50V supply depends on the +50 unregulated voltage. The 130 V
supply also depends on a good +50 V. You might want to check the caps
C808 and C809 that's where I found a bad cap when troubleshooting mine.

bob.

On 4/2/2020 9:15 AM, Eric wrote:
That is very true. I am going to get it on the bench again tonight I have a sneaking suspicion I have a massive ripple problem given what I saw on the scope last night. I was able to confirm that the plugins will generate a trace on a working 7K frame so that is good. The -50 is the main reference supply for the frame.

What I saw last night was I was getting very now intensity pulses on the z output of the main board. But it looked like they were riding on about 40mV pk-pk of ripple so I am pretty sure that is not supposed to be there. Getting to the bulk caps in these is a nightmare but hey that is where the fun is.

Eric
-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of
Oz-in-DFW
Sent: Thursday, April 2, 2020 12:05 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] A sick 7603 can it be restored?

Its been forever since I worked on one. One dim memory I have of these is that all the supplies are interrelated. Anything dragging one down messes up all of the others. They were a pain to troubleshoot.










My role: Moderator or Co-Owner

 

To Everyone,
I need to clarify something:
It is true that I am a CO-OWNER of TekScopes, along with Michael Dunn the Founder. There is very little involved in being a co-owner - we make decisions regarding the future of TekScopes, and I occasionally ask Michael for guidance. As a group owner I have absolute power over what happens. That power is for extreme situations only. Persuasion and peer pressure are always more effective. I would never use that power because I disagree with something someone said.

My real responsibility is to be the MODERATOR keeping TekScopes focused on the original purpose Michael intended when he created TekScopes: All about classic Tektronix test equipment, its use, repair, and collecting.

There is nothing about TekScopes that would prevent anyone from expressing themselves freely. I would never knowingly prevent posts from anyone as long as they pertain to Tektronix. I may disagree, I may express my disagreement, but that should never be interpreted as a warning of any kind. Occasionally a thread will wander so far from the purpose of TekScopes that I will request interested parties continue their discussion off-line.

I would not be able to benefit from all the fabulous Tek instruments I own without the help of others. In that regard we are all fortunate to have the support of vintageTEK, TekWiki, and TekScopes.
It is unreasonable to expect electronic equipment, even when designed with the best possible engineering practices, to last forever. This is not a requirement for the test equipment Tektronix makes.

What makes our obsession (weakness, labor of love, pastime, etc.) interesting is the challenge of maintaining these instruments in working condition. If they worked forever there would be little need for TekScopes.

Dennis Tillman W7pF




--
Dennis Tillman W7PF
TekScopes Moderator

Re: 2445A slow

tekscopegroup@...
 

On Sat, Apr 4, 2020 at 07:20 AM, n4buq wrote:


I know my 2445 has the snubbers. In an effort to find what had smoked, I
decided to shotgun all the larger electrolytics as well as the the snubbers.
After replacing the electrolytics (and, unfortunately, finding them all
testing good), the last thing I replaced was the snubbers and it was only then
that I noticed that one of them had blown through a crack on one end. Wish
I'd seen that one first but maybe I bought some extra time with new
electrolytics on those boards.
You took the effort to get into the power supply which can be quite a chore, specially the first time. So be happy you are now hopefully all done with it for a good while. No point going in there and only doing an incomplete recap that will force you to to it all over again in the near future. No such thing as buying some extra time with aging electrolytic caps, specially in this case with well known failure statistics.

Re: Tek 576 Curve Tracer HV Replacement Transformer

 

Chuck,

A couple of things.

1) I don't challenge Dennis's ownership of the group. I respect his directives as moderator of the group.
2) You cannot possibly know how old and wise I am, not by a long shot. And vice versa.

Before Dennis's post, I never felt attacked or challenged in this group.
I don't know why he got so upset over my critique of Tektronix.
He wanted to know which companies I consider comparable or superior to Tektronix, and I told him so.
Schlumberger was created by two incredible ingenious and smart brothers, and rose to fame like Tektronix did.
Their services are famous in their industry like Tektronix equipment is famous in the electronics industry.
Their excellence in service is backed by the excellence of their equipment.
It dedicates one of the largest segments of their income to research and development.
Schlumberger sells measurements (logs), and their product does not have an expiration date.
Oil wells don't have an expiration date either, there can be valid questions about them after 50 years.
If a client wants to know about some logs made in 1970, Schlumberger will help interpret them.
In my opinion, the service provided by Schlumberger is superior to the one of Tektronix.

I don't post here for chest trumping. I enjoy the exchange of knowledge in the topic of electronic design and oscilloscopes in particular.
I am not the only one here with plenty of experience who like to communicate it to others and help them with their problems.
And I respect and appreciate the experience of other members of this group, who have helped me on various occasions.
I believe that one important reason equipment gets rusty is because their owners have not yet found the way to fix them.
And our knowledge is a noble gift we should all be able to give.

Ernesto

Re: vintageTEK scanned transformer drawings for 120-0998-01 and up

Mlynch001
 

Acrobat usually automatically installs their PDF "virtual printer" as an integral part of the program which you are using. I have never seen this "Virtual Printer" have to be installed separately and I have been using various versions of Acrobat PRO and Acrobat Reader for decades with Windows Vista, XP 7,8 10, etc. . If you go to your Windows control panel, look for the ADOBE PDF "printer" icon. This is the virtual printer that allows you to create a separate PDF of individual or groups of pages from inside a larger PDF. My Window 10 version actually shows 3 virtual PDF printers installed. It should be a simple matter of selecting this as your "printer" from the drop down menu of the Print dialog window.

ADOBE PDF
Microsoft Print to PDF
Quicken PDF Printer.

Good luck

--
Michael Lynch
Dardanelle, AR

Re: 465 dot only, no sweep

Bert Haskins
 

On 4/5/2020 10:17 AM, james_55@... wrote:
After drawing up a list of every component in the -8v rail, I set about testing them all.

As R1565 (8K) was being removed it revealed itself to be broken in two. So that is some kind of progress, and I have temporarily installed a 10k which took the -8v rail down to -6.09v

By switching over op-amps U1554 and U1524 there were clear differences on the -8v, +5v and +15v rails, so therein lies another part to be ordered.

If I select the X10 Mag, a small (1") sweep does now appear, but without any vertical deflection.






I was trying to attach the power section of the schematic here
Go back to the op amps and clean the pins and sockets.

Reinsert the chips and wiggle them around.

Then remeasure and see if you have a different result from your step two .

You may just have a poor contact problem.

Been there, done that.



Re: 2445A slow

Chuck Harris
 

There are a couple of possibilities, all easily
tested.

1) Your scope is not getting any input signal.
2) your scope is broken so the input signal is not
getting displayed in X-Y mode.

Try putting a sine wave on channel 1, and another from
a different source on channel 2, while in X-Y mode.

You should get an unstable pattern that, with the right
amplitude settings will fill the screen.

If you do, the problem is with the curve tracer.

The problem could be as simple as the AC/DC/GND/50 ohm
switches are in 50 ohm, or ground.

-Chuck Harris

Steve wrote:

Also, I have set ch1 volts and ch2 mv accordingly for my curve tracer so I’m not quite sure what you mean by setting X and Y unless I’m just not understanding exactly what you’re saying that I need to do. Probably my error. I’m going to attempt to interpret engineer language and read a bit more of the manual to see if I can get a better grasp of this scope. I’m sure there are so many reading this saying to themselves.............(Really?) lol

Re: Tek 576 Curve Tracer HV Replacement Transformer

Chuck Harris
 

Ernesto,

A couple of things:

1) Dennis owns this group... plan accordingly.
2) You are not the oldest, nor the wisest member of this
group... not by a long shot.

We avoid chest thumping, because it results in wars of words,
rolled eyes, ruffled feathers, and hurt feelings...

And, the inevitable bloodshed rusts the equipment.

-Chuck Harris

Ernesto wrote:

Hi Dennis,

I am sorry if I made you waste your time over my rant. You probably have the fortune of having much life time ahead to acquire maturity and not get upset over the rant of an old man.

I have experience with excellence, but not in the consumer products market. I worked practically all my life for a service company in the oil industry, Schlumberger. If you are familiar with this industry, you must know that this company has always been and is by far the leader in measurements in oil wells, or "well logging". Its presence is all over the world. It provides excellent service to its customers, the oil companies, and they cultivate the relationship because this company can do things no other one can, important in a highly expensive environment. After working in the field, I designed for over 30 years all sorts of electronic equipment and data acquisition systems, so I know about quality and reliability in severe environments. This equipment has to work in the wells at a temperature range from freezing to 350 degF, under enormous pressures, support the banging of transportation to well sites and handling at an oil rig (people there are not suave), and yet make delicate complex measurements for long hours without failure. Rig time is very expensive, and a little failure can mean long hours of down time of the rig, at tens of thousands of dollars. Schlumberger has developed measurements using any imaginable physical magnitude, including nuclear magnetic resonance, to find, qualify and help extract that "black gold" from down there.

My former company does not sell its sophisticated equipment, it sells its service using it, at indecent high prices... (until now?). I used to do measurements non stop for up to 2 days at an oil well, and our customer was like God. It is the attitude of service or lack of it what drove my opinion of Tektronix, not the quality of their equipment. If so many VOLUNTEERS put their time to cultivate that legacy which helps hold high the image of the company, why cannot they have ONE person among their 4500 employees who is a liaison to these volunteers and their members, and shows interest for their problems and offers solutions?

BTW, I also have esteem for the 7854 oscilloscope, especially its service manual. I am reading it now to learn the principles of the early digitizing system. The inverter and HV supply are close to the ones in my 7704, and if I experience a failure in the HV transformer I will do like I did with the 547, find a solution around it, or build one myself, of course with the help of the TekScopes community.

Regards,
Ernesto

Re: 465 dot only, no sweep

james_55@...
 

After drawing up a list of every component in the -8v rail, I set about testing them all.

As R1565 (8K) was being removed it revealed itself to be broken in two. So that is some kind of progress, and I have temporarily installed a 10k which took the -8v rail down to -6.09v

By switching over op-amps U1554 and U1524 there were clear differences on the -8v, +5v and +15v rails, so therein lies another part to be ordered.

If I select the X10 Mag, a small (1") sweep does now appear, but without any vertical deflection.






I was trying to attach the power section of the schematic here

Re: OT Seeking Sencore CA55 Capacitor Analyzer CA55

Michael A. Terrell
 

Have you contacted Sencore? They may have it, but not online. They scanned
and posted manuals that people wanted, not every paper manual they still
have.

On Sat, Apr 4, 2020 at 3:23 PM Yiu On Tony C via groups.io <tonycheung_hk=
yahoo.com@groups.io> wrote:

Dear Members :

I am sorry , it is OT topic, I am being seek the manual/ schematic/
calibration information etc....

CA55 of Sencore is a capacitor analyzer, I cannot find related service
information on web site .

Regard
Tony Cheung
APR 5 2020



Re: Tek 576 Curve Tracer HV Replacement Transformer

RustySparks
 

Michael, thanks for your work.
I am interested in the HV transformer for type 453 scope.
Harry Oder

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Mlynch001
Sent: Sunday, April 05, 2020 12:20 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Replacement Transformer

On Sat, Apr 4, 2020 at 11:56 AM, Dennis Tillman W7PF wrote:


Hi Michael,
Thank you for showing others what can be done by a dedicated member of
TekScopes who refuses to let a valuable instrument collect dust.

Would your supplier be willing to make replacements for other Tek HV
transformers where there is enough demand to meet his minimum order?

HV Transformers endure incredible electrical stresses and there are
very few potting materials that are stable over a product lifetime
that can last decades. They are all going to fail eventually.

Dennis Tillman W7pF
--
Dennis Tillman W7PF
TekScopes Moderator
Dennis,

Thank you for your kind words and recognition of my project. I am just happy to be able to do my small part in keeping these wonderful machines in operation and helping others do the same. Giving back to other members is just a small way to say "Thank You" for all the help that I have received.

I would be interested to hear what other transformers would be of interest to the group. We would probably need to do batches of 10 or more to make it feasible. I could do something like what was done on the 576 Project.

I had a long discussion with the factory sales people while negotiating and attempting to talk them into the idea of doing this 576 transformer for me. They indicated some interested in doing others for me on a small batch basis, but no firm commitment. Whatever they do will need to be built using similar available cores and other materials. I would need to reach out to them with a potential candidate. Since we have most of the prints for the various instruments let me know which one and I can then reach out to the factory for a proposal.

Perhaps the group can come up with a model that they deem "High priority"?

Sincerely,

--
Michael Lynch
Dardanelle, AR

Re: vintageTEK scanned transformer drawings for 120-0998-01 and up

satbeginner
 

So, it looks like it is dependent on having the "print to PDF" printer option available in Windows.

I believe there are additional programs available to add this function to previous Windows versions.

Re: vintageTEK scanned transformer drawings for 120-0998-01 and up

Michael A. Terrell
 

Windows7, abd Adobe Reader will let me print to paper, but not to a new PDF.

On Wed, Apr 1, 2020 at 6:14 AM satbeginner <@satbeginner> wrote:

I use Windows 10, and Adobe reader, from there I select print, select
"print to PDF" as printer, and choose "selected pages", like 7 - 9, and it
will create a new off with only 3 pages...



Re: Tek 576 Curve Tracer HV Replacement Transformer

John Crighton
 

Hello Michael,
well done on your transformer project.
I am interested in a High Voltage Multiplier for a 465 oscilloscope.
Maybe put a kit of parts together to make a multiplier.


Hello Dennis,
I think you mentioned that you have contacts at Tektronix and that
you know many Tektronix ex employees.
Could you do me a favour and ask around for the schematic diagram
for the Power Supply in the TDS 320 oscilloscope.

Regards,
John Crighton
Sydney

----- Original Message -----
From: "Mlynch001" <@mlynch001>
To: <TekScopes@groups.io>
Sent: Sunday, April 05, 2020 2:19 PM
Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Replacement Transformer


On Sat, Apr 4, 2020 at 11:56 AM, Dennis Tillman W7PF wrote:


Hi Michael,
Thank you for showing others what can be done by a dedicated member of
TekScopes who refuses to let a valuable instrument collect dust.

Would your supplier be willing to make replacements for other Tek HV
transformers where there is enough demand to meet his minimum order?

HV Transformers endure incredible electrical stresses and there are very few
potting materials that are stable over a product lifetime that can last
decades. They are all going to fail eventually.

Dennis Tillman W7pF
--
Dennis Tillman W7PF
TekScopes Moderator
Dennis,

Thank you for your kind words and recognition of my project. I am just happy to be able to do my small part in keeping these wonderful machines in operation and helping others do the same. Giving back to other members is just a small way to say "Thank You" for all the help that I have received.

I would be interested to hear what other transformers would be of interest to the group. We would probably need to do batches of 10 or more to make it feasible. I could do something like what was done on the 576 Project.

I had a long discussion with the factory sales people while negotiating and attempting to talk them into the idea of doing this 576 transformer for me. They indicated some interested in doing others for me on a small batch basis, but no firm commitment. Whatever they do will need to be built using similar available cores and other materials. I would need to reach out to them with a potential candidate. Since we have most of the prints for the various instruments let me know which one and I can then reach out to the factory for a proposal.

Perhaps the group can come up with a model that they deem "High priority"?

Sincerely,

--
Michael Lynch
Dardanelle, AR




---
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Re: Capacitor testing

 

Hi Randy,
A Systron Donner 320V / 2A power supply must weigh at least 100 lbs and be very scary to use.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Randy Newman
Sent: Saturday, April 04, 2020 2:30 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Capacitor testing

Hi Roy:
I have ( in my previous work lives) reviewed various of the MIL-Cxx spec’s, and remember reading about reforming electrolytics. Sadly, I have forgotten the one containing the reforming procedure. Which particular spec are you referring to?
Btw..I have a Systron Donner 320v, 2A supply which I have been waiting to use on reforming.
The proverbial “one of these days....”





--
Dennis Tillman W7PF
TekScopes Moderator

Re: Tek 576 Curve Tracer HV Replacement Transformer

Mlynch001
 

On Sat, Apr 4, 2020 at 11:56 AM, Dennis Tillman W7PF wrote:


Hi Michael,
Thank you for showing others what can be done by a dedicated member of
TekScopes who refuses to let a valuable instrument collect dust.

Would your supplier be willing to make replacements for other Tek HV
transformers where there is enough demand to meet his minimum order?

HV Transformers endure incredible electrical stresses and there are very few
potting materials that are stable over a product lifetime that can last
decades. They are all going to fail eventually.

Dennis Tillman W7pF
--
Dennis Tillman W7PF
TekScopes Moderator
Dennis,

Thank you for your kind words and recognition of my project. I am just happy to be able to do my small part in keeping these wonderful machines in operation and helping others do the same. Giving back to other members is just a small way to say "Thank You" for all the help that I have received.

I would be interested to hear what other transformers would be of interest to the group. We would probably need to do batches of 10 or more to make it feasible. I could do something like what was done on the 576 Project.

I had a long discussion with the factory sales people while negotiating and attempting to talk them into the idea of doing this 576 transformer for me. They indicated some interested in doing others for me on a small batch basis, but no firm commitment. Whatever they do will need to be built using similar available cores and other materials. I would need to reach out to them with a potential candidate. Since we have most of the prints for the various instruments let me know which one and I can then reach out to the factory for a proposal.

Perhaps the group can come up with a model that they deem "High priority"?

Sincerely,

--
Michael Lynch
Dardanelle, AR

Re: Tek 576 Curve Tracer HV Replacement Transformer

Don Bitters
 

Amen!! I concur.Don Bitters

Re: WTB: Parts for P6131 Probe

s.r.bell@...
 

Did you get any response to your request?
I have some probe accessory kits (020 1956 00) that might suit the P6131. They include all the necessary ground leads but no retractable hook tips.
I am on the other side of the world (New Zealand) so postage might be a little expensive and in any case I can't post for a month because the whole country is locked up at the moment due to coronavirus.
If you are interested email me on s dot r dot bell at snap dot net dot nz