开云体育

On Wed, Apr 9, 2025 at 11:34 AM, on6jz wrote:

Does anyone have any tips on where I can look

There is a long thread on the 2712, which was previously posted.
You could search the messages for "tek 2712 freezes during startup"
There might be some clues there.

--
Roy Thistle

Hello Matthieu:

Unless there has been some Hack I am not aware of, you cannot view the Spectrum Analyzer and Oscilloscope at the same time. So, you are correct, this is reserved for the MDO4XXX Series and later.

Rich

Hi,

I have a Tektronix MDO3024 scope. Working great !

I would like to have on the screen the analog CH1 screen and the RF signal.

Is it possible on the MDO 3000 series or it is only with the MDO 4000 series ? Thank you

Matthieu

On Sat, Apr 12, 2025 at 01:49 PM, Jim Adney wrote:

perhaps they were able to control their production carefully enough to make
the ageing and selecting unnecessary.

AFAIK, the 'aging' was significantly about... but not only about, stabilizing the emissivity of the cathode.
Again... AFAIK... despite decades of research ... the exact mechanics of thermionic emission from oxide-coated cathodes... from substances like barium oxide... remain somewhat mysterious.
At least from the published literature.
I'd speculate that give cathode X, constructed with process Y... the engineers knew that Z amount of hours under process alpha... for instance... achieved a stable emissivity...within the desired specification.
I don't know... but I don't think... the scientists... knew... or even now know... what was happening in microscopic regions, and layers, of the thermionic emissve materials that were used in the manufacture of cathodes.
Even if they did... IMO... its akin to heat treating steel... you may know the final microscopic properties of the material; but, you have no way to effect them directly.
--
Roy Thistle

I read Roy's posts on this tread and I did not find them offensive or aggressive.
However, I do believe that the recapping discussion points have been sufficiently covered so there is no need to continue.
Cheers,
Tom

Posts to this topic are now on moderation.

Roy,

I've had a few complaints about your posts on this thread. If I receive more, I will need to consider banning you from the group, which I'd prefer not to do.

David (Moderator).

Me too ?

Roy

Your tone is highly aggressive, and I think you're just looking for a fight, for some reason which it's above my pay grade to understand.

I'll debate you anytime on technical accuracy, but I decline to engage your ego.

There are enough contradictions in your statements to make mincemeat here.

End of subject.

Menahem

Thanks for this collection, just like a trip down memory lane. Nice to see all the Ampex manuals being saved, I kept hoping to see an ACR-25 collection.
So many shops had a bookcase full of the same items, sadly most have been carted off to the shreader.
Thanks again for all your great work.

Gerry (broadcast engineering retired)

Roy

What's your point?

Menahem

Hello,

I have scanned some Tektronix Television Products related material, including:
Tektronix TSG7 Instruction Manual
Tektronix SPG1 SPG2 Instruction Manual (has information regarding the SPG2A update)
Tektronix 1480-series Waveform Monitor Instruction Manual (with schematics)
Tektronix Television Products Catalog 1980

They can currently be found on my Internet Archive account ( ) . I will see about getting them up on the tekwiki.

Also I am curious if anyone has any manuals or materials for TSG7 "Opt AB" (manual 070-4908-00) and SPG2A "Opt AA" (manual 070-4905-00). I am able to find descriptions of them in other service literature, but no manuals for themselves. Nice to see the 1485 "Mod W5F" is on the tekwiki!

I have a big binder of Tektronix TV Products from 1976 that I will try and scan and upload soon, too.

-Michael Bierlein

Some more trouble. Blank screen.
Still boots because I have the 1kHz on the probe comp signal and when put on CH1 it goes from "ready" to "trig'd" from the trigger "main level" pot.
I'll measure the crt's power supplies next.
Renaud

Actually, I spoke (or asked) a little too soon. I was browsing an area of my basement behind the cobwebs and discovered I had this metered variac laying around. I'm assuming this will do the trick.



David

Roy,
Generally, it's best to troubleshoot a problem and solve it.

BUT, in THIS case, what we have here, thanks to all the efforts of these capable and experienced techs here, is that ALL the problems have ALREADY been "Troubleshot", and condensed into ONE bunch of tasks to do now. These problems and defects are now "KNOWN".

So, why try to reinvent the wheel, when somebody else has already travelled the road down which you want to walk, and solved the problem which you have now?

That is the concept of SOLVING "KNOWN" defects, and that is the rationale behind the Recapping exercise (which in the case of my kit, includes not only capacitors, but resistors as well)!

Those capacitor problems of c. 1999 which you mentioned have NOT gone away - there is NO SHORTAGE of Chinese capacitors made in 2025, which still fail in the same way as those 26 years ago, and understanding the Chinese mindset of "profit at any cost", we can expect the no-name and counterfeit components to continue to fail in the future. It's got nothing to do with anti-Chinese prejudice - it's simply the way that China does business.

Therefore the choice of BRAND and Model is very important, far more important than the cost.

And if the tech who does the work is sloppy and unprofessional, then of course the chances of his damaging the PCB and causing catastrophic failure are present and real, and it makes no difference whether he replaces one cap or 50 caps.
By the same token, a thoroughly professional tech will have 100% success, whether he replaces one cap or 50.

Generally most of the techs who are active in this forum have extremely high professional work standards and technique, and can be trusted to do work with 100% success rate.

"Learn from the mistakes of others, because you will not live long enough to solve them all yourself"

Menahem

Ironic that the tek logo looks a bit coarsely digitised for an analog scope

The aging process for 157-0125-00 is documented on page 36 of the tube aging pdf on tekwiki.



It’s also mentioned on page 110 in the tube specification list which shows the tek part numbers of the raw tubes they would have used and later reassign the part number to the selected one



Nothing about specific brand names but still interesting info if you haven’t seen those documents

It's great you've submitted this information here. I'm sure this will help
some folks down the line. Way to go.

On Sat, Apr 12, 2025 at 6:51?PM rich.meyer@... via groups.io
<rich.meyer@...> wrote:

The Tektronix 155-0124-00 is a hard part to find. I was able to repair my
2235 scope with an alternate part. I used a Tektronix 234-1008-20 which
was made by Maxim for Tektronix. The Military version of the 2235 was the
AN/USM488. The Military National Stock Number (NSN) for this part was
5962-01-062-7562, which is also the 234-1008-20. I located this part on
eBay, replaced it, and got my 2235 operational again.

The Tektronix 155-0124-00 is a hard part to find. I was able to repair my 2235 scope with an alternate part. I used a Tektronix 234-1008-20 which was made by Maxim for Tektronix. The Military version of the 2235 was the AN/USM488. The Military National Stock Number (NSN) for this part was 5962-01-062-7562, which is also the 234-1008-20. I located this part on eBay, replaced it, and got my 2235 operational again.

Jim,

I had gotten some of those very tubes in the 1990s. I didn't use them until I (tried) to calibrate my 547 a few years ago and found them a little less than wonderful than actual 6DJ8s to the point that I wondered if they were even related to 6DJ8s. They didn't always work well in place of 6DJ8s. I hope you have better luck with yours.

(As I have only 1A1 plug-ins, I can't help you with the chassis rods.)