Date   

Re: What is a mod BG to 7103 or 7104?

Clark Foley
 

John,

I have posted a photograph of a few R7103s in a rack and ready for an underground test. You will see the same hardware on the bezel. The photo album is named Mighty Oak.
https://groups.io/g/TekScopes/photo/267445/3290449?p=Created,,,20,2,0,0


Re: A scope for sale in Massachusetts

 

Mark,

Wow, that is a tight call from such a dark picture. I had a look at the TekWiki page, and while you are obviously right, I would have had a very hard time figuring that out. I'm not at all surprised, however, that the scope is being misrepresented by the seller, given the quality of the rest of the presentation.

So, regardless of the current value or utility of this scope (which are separate things), I'm puzzled about what the original target market and use for these scopes was. My point of view on these matters is admittedly limited, both by my relative youth, and by the applications to which I have been exposed, but I don't understand why you would build a scope that directly drives the deflection plates when the bandwidth is so low, even for 1962. Was (is?) there really a use case for a scope with only 10 MHz bandwidth and dual delayed time bases when you could have had a 30, 50, or 100 Mhz scope?

-- Jeff Dutky


Re: Tektronix 570 Curve Tracer

David Simpson MM6ACI
 

Its great to read about other folk's projects. Certainly those relating to valve/tube testing. It also enhances my belief that hybridisation of vintage T/Eq with other vintage items &/or modern analogue or digital items is a viable option for enthusiasts.
I've opened a photo album of a handful of past modest project endeavours relating to valve testers & old scopes. Just to show where I'm coming from in relation to aspiring to reach up into the heady heights of Tektronix technology. Regards, Dave


Re: A scope for sale in Massachusetts

Mark Vincent
 

Jeff,

Even with the dark photo in the ad, it is a 565 with P2 phosphor. The placement of the knobs below the screen and what writing that can be read were compared to the light pictures of a 565 online. It is a 10mc scope, NOT 100mc as the owner says. This has already been listed a number of times over the past several weeks.

Mark


File /TM5xxx Pass Transistor List New.pdf uploaded #file-notice

TekScopes@groups.io Notification <noreply@...>
 

The following files have been uploaded to the Files area of the TekScopes@groups.io group.

By: Jared Cabot <jaredcabot@...>

Description:
A reformatted version of the fantastic TM5xxx pass transistor list by Jerry Scheltgen and Dennis Tillman to improve readability. Now updated with TM504A transistor data!


Re: Tektronix 570 Curve Tracer

ChuckA
 

Martin,

I read your posts about using the Metrix with a 576, got me thinking about trying the same thing with my New London 901A Transconductance Analyzer. Seems to be similar to your Metrix, all connections are through jumpered binding posts.

It worked perfectly.

The unit has 4 DC power supplies Plate and screen 0-300V up to 150mA, Grid and Supressor 0 to +3V and 0 to -150V. Filament supply 0 to 3VDC and 0 to 150VAC

It measures Transconductance directly on 5 scales up to 50,000micromhos

Like your Metrix it weighs more than the 576 and takes up almost 2' square of bench space. I wish I had thought of this before I spent the money and time on my custom unit.

Chuck

--
See Early TV at:

www.myvintagetv.com


Re: Another solution for the 547 HV transformer problem

Dave Wise
 

Clever idea! I wonder: how about a dropping resistor in series with the tripler input? If deflection factor stays constant as you vary intensity, you don’t have to de-wind.

I salvaged a handful of HV transformers from Stan Griffiths’ estate. I sent some to Chuck; I’ll go figure out what I kept.

Dave Wise
PS – Don’t forget I published a low-tech recipe for winding your own transformer. That was 453 but it’s easily adaptable to 547. Photo album and topic, “453 HV Transformer Rewind”.

=============================================================================
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David Kuhn via groups.io
Sent: Wednesday, August 25, 2021 7:16 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Another solution for the 547 HV transformer problem

I saw your post on Facebook; great job. Question: Are 535 transformers
easy to get? I would imagine the 535 still around have been fixed up and
restored. The 547 is a better scope than a 535, so to sacrifice on to save
a 547 may be acceptable, I donno???

On Wed, Aug 25, 2021 at 12:49 AM Morris Odell <vilgotch1@...> wrote:

A friend of mine named Deon Vandenberg recently acquired a 547 scope and
as expected, the HV transformer had the classic thermal runaway problem.
The only cure for this is to replace or rewind the transformer and as Chuck
Harris is not currently providing this service, we had to find an
alternative solution. I say "we" because although Deon lives over 1000
miles away from me (Australia is a big country!) we we were able to
collaborate by internet and phone.

Deon has managed to modify a transformer from another junked scope to
provide virtually identical function to the original and the 547 is now
working perfectly. He has kindly consented for me to upload his description
of what he did in the hope that it will help others.

If you're interested, I have uploaded a word file to the "547 hv
transformer" folder in the files section.

Comments welcome!

Morris






Re: Another solution for the 547 HV transformer problem

David Kuhn
 

I saw your post on Facebook; great job. Question: Are 535 transformers
easy to get? I would imagine the 535 still around have been fixed up and
restored. The 547 is a better scope than a 535, so to sacrifice on to save
a 547 may be acceptable, I donno???

On Wed, Aug 25, 2021 at 12:49 AM Morris Odell <vilgotch1@...> wrote:

A friend of mine named Deon Vandenberg recently acquired a 547 scope and
as expected, the HV transformer had the classic thermal runaway problem.
The only cure for this is to replace or rewind the transformer and as Chuck
Harris is not currently providing this service, we had to find an
alternative solution. I say "we" because although Deon lives over 1000
miles away from me (Australia is a big country!) we we were able to
collaborate by internet and phone.

Deon has managed to modify a transformer from another junked scope to
provide virtually identical function to the original and the 547 is now
working perfectly. He has kindly consented for me to upload his description
of what he did in the hope that it will help others.

If you're interested, I have uploaded a word file to the "547 hv
transformer" folder in the files section.

Comments welcome!

Morris






Re: Tektronix 570 Curve Tracer

David Simpson MM6ACI
 

Some folk might ask why a "Standardised Valve/Tube requires "pure" DC applied to all electrodes for the standardising process. Answer - because the manufacturers have always tested their valves with DC. Reason - from DeForrest's early WW1 era triodes through to the early 1930's, all valves just used battery sourced DC . I.e. an LV battery or cell(usually 1.2V or it's multiples) for "Filament"(heater + cathode), and HT's from a dry cell pack(60V,90V, 120V, etc.). Grid Bias could either be a single cell, or an LV dry battery. (No "cathode bias" back in those old days.
So, early pre-WW2 valve testers were also DC battery supplied. However, once AC/DC &/or fully mains rectified radios appeared in the early 1930's, HV valve testers were needed for later types of higher Plate(Anode) & Screen(G2) voltages. The major valve tester manufacturers then changed to the full P-P mains sourced voltages for testing. Maily because the Capacitors(Condensers) & Chokes required for FW or HW smoothing of rectified voltages would've been excessively large & heavy for their testers. I'm not going to go into the "meter backing off" methodes & circuitry, because the likes of AVO, Mullard, Hickok, Jackson, etc, all used slightly different methods & relied heavily on the stability of the electricity mains supplied to radio shops & domestic premises.
To sum up - decent AC working valve/tube testers will give pretty good testing results compared to DC working testers as long as they are regularly (weekly or monthly) tested with a "standardised valve/tube", And, (most important) their AC mains supply is checked for each valve/tube every few minutes. AVO call it "Set AC" & is displayed on the tester's meter. DC Testers are better, though.
Returning to the Tek570, if I ever get my hands on one, I suspect that its testing results would be beyond reproach. For folk with the technical know-how - Jac's excellent ideas on 576's are really something to aspire to. Here in the UK, the "Sussex" project now has a decent following. Then for folk with very deep pockets & exceptional software skills - the "RoeTest" kit project is the "bee's knees" I suspect.
Me - I just built my DC Tester out of parts from other vintage but redundant items of analogue test equipment from yesteryear. Probably cost less than £200. Why would I want to acquire a 570 - because the UK's most prolific & highly respected valve tester restorer/collector (over a hundred items), now approaching 90 & with poor eyesight - - Dennis Tabor - - told me that the Tek570 had been the best tester he'd ever had.

Regards, Dave

PS. Does anyone know the email address for Dick Anderson from Ohio, whome I mentioned 2 days ago ?


Re: Tektronix 570 Curve Tracer

 

Hi Jac,

what is so special about Gm measurement?

The U61 has Gm-values for each tube in his measurement booklet. You then need to vary the emission-setting of G1 plus-and-minus 0,5V and get Gm by evaluating the corresponding excursion of the anode current meter. Of course you cannot read it directly on a dial, and if you want to have Gm for other settings it gets tiresome.

Or is Gm something else than delta-anode-current / delta-grid-voltage?

cheers
Martin


Re: Tektronix 570 Curve Tracer

emissionlabs
 

Some tube testers work so crazy, you can only calibrate them with a tube of known data. This was called a standardized valve by the AVO company. It can be any tube, and does not have to be a Bogey tube. A Bogey tube is one which performs like the "Avarage" tube, as the data sheet. Only ver few will be a Bogey tube, so it takes a lot of testing before you have found one. But for some lower level tube testers, which have only settings for "6L6", and you don't have the faintest idea what the heck this tester is doing internally, you can only use a Bogey tube to calibrate such a tester. All other testers can use a standardized valve, or the better ones can be calibrated without a tube. Like the TEK576 of course, is calibrated by itself, and not by attaching known parts to it.

Connect the 567 to the Metrix U61B seems easy to me, and a great idea. LIke this I can test with any tube socket I like, any heater voltage, and see everything I do, on the U61 meters. The U61B has banana connectors for all electrodes, allowing to connect a cable to it each electrode. Also, allowing to interrupt each electrode, and connect something external to it. Like this, you can take the heater and G2 and G3 from the U61B, and take G1 and Anode Voltage from the TEK576. And then the TEk576 already works, without any adapter boards! Seems really easy, and the device which was "made" for this was the U61. Just I was wondering about unexpected problems and complications, such as oscillation, etc. It works 25x faster to take good advice, than inventing the wheel myself.

A similar tube tester, with the same universal lab connections is the Neuberger 370 and 375, there are more around of those. But no matter if it's a U61, or 370, 375, they cost a fortune. So only nice when you have one anyway.

Probably a Hickok 750 tube tester can also do this! It will attach the heater voltage directly to the socket. And it has a capacitor stabilized, variable DC voltage which you can connect to where you like, also G2, and connect even the panel meter to it, so you can see voltage and current. Though intended for voltage regulator testing, this DC voltage can be connected to any random electrode. You do need to make a cut in the anode and in the G1 lines, to connect this to the TEK576. Like with a switch, and attach two BNC connectors to it. Same as the U61B method. But Hickok 750 is a lot easier to find, not so expensive, and it would turn the TEK576 into a very nice tube curve tracer. Besides you can pre test the tubes then on the Hickok 750, and get Gm data that way too.
Well, just ideas.

Jac


Re: Type M Cracked Channel Position Pots

 

snapdiode,

after reading through the wiki page on Delrin I doubt that the solvent I have will work, but I'd still like to give it a try, in case the plastic is something other the POM.

I'm wondering if my original plan to epoxy the parts might still work, not by epoxying the broken parts together at the cracks, but by potting the entire part in a shell of epoxy. I could add plugs to the shaft and set screw holes to keep them from filling with epoxy, and hope that the epoxy itself is strong enough to hold the piece together. Alternately I could reinforce the piece with a ring of bus wire before potting it, which would relieve the epoxy of most or all of the stress from the tightened set screw.

Finally, I wonder if the pots can be disassembled, and new caps constructed of some other material.

-- Jeff Dutky


Re: Another solution for the 547 HV transformer problem

momemeca
 

Hello Morris,
Rick here … Is Deon back from Japan? Also, when lockdown is over, I would like to come for a visit and pick up that carcass ;-)
Cheers.

On 25 Aug 2021, at 14:49, Morris Odell <vilgotch1@...> wrote:

A friend of mine named Deon Vandenberg recently acquired a 547 scope and as expected, the HV transformer had the classic thermal runaway problem. The only cure for this is to replace or rewind the transformer and as Chuck Harris is not currently providing this service, we had to find an alternative solution. I say "we" because although Deon lives over 1000 miles away from me (Australia is a big country!) we we were able to collaborate by internet and phone.

Deon has managed to modify a transformer from another junked scope to provide virtually identical function to the original and the 547 is now working perfectly. He has kindly consented for me to upload his description of what he did in the hope that it will help others.

If you're interested, I have uploaded a word file to the "547 hv transformer" folder in the files section.

Comments welcome!

Morris





Another solution for the 547 HV transformer problem

Morris Odell
 

A friend of mine named Deon Vandenberg recently acquired a 547 scope and as expected, the HV transformer had the classic thermal runaway problem. The only cure for this is to replace or rewind the transformer and as Chuck Harris is not currently providing this service, we had to find an alternative solution. I say "we" because although Deon lives over 1000 miles away from me (Australia is a big country!) we we were able to collaborate by internet and phone.

Deon has managed to modify a transformer from another junked scope to provide virtually identical function to the original and the 547 is now working perfectly. He has kindly consented for me to upload his description of what he did in the hope that it will help others.

If you're interested, I have uploaded a word file to the "547 hv transformer" folder in the files section.

Comments welcome!

Morris


A scope for sale in Massachusetts

 

No connection with the seller, but I found this while trolling for anything that mentioned “tektronix” and thought others might be interested: https://www.ebay.com/itm/Tektronix-Dual-BEAM-dualTrace-100Mhz-Oscilloscope-/203577968782

I have messaged the seller for more information and better pictures.

— Jeff Dutky


Tek 524AD

byterock@...
 

have a chance to pick up a Tek 524AD

What would be a fair price for one of these in fair shape (need re-capping) with, cart, manuals, a few probes and a 'supposedly' an extra set of tubes?


Re: Tek 7103 found at auction in NM

nonIonizing EMF
 

I'll read into the photos some more next. Looks like I'm caught not reading into and/or critical thinking just yet.

Figured I'd post this related link too since might provide some insight with some other links noted worth reading. https://www.eevblog.com/forum/projects/voltage-regulator-tubes-vs-zeners-(tubes-has-better-stability)/

Not sure if you, or anyone else for that matter, have any observations in the above reference regarding if I'm preaching to the choir. Looks like a great read when I have the time to critically think, on the vacuum tube regulator part subject and logic related, that's new to me.

James

On Tue, Aug 24, 2021 at 03:51 PM, Dave Wise wrote:


There’s only one TL431 circuit.
https://groups.io/g/HP-Agilent-Keysight-equipment/photo/68333/805597?p=created
,,reference+replacement,20,2,0,0
Everything else is a Kick Start.

My experience is that the supply output is slightly noisier with TL431 but
within spec.


WTB: Cover for TM-515

greenboxmaven
 

Does anyone have a cover for a TM-515 power module they would part with?  I just got one of them, it is dirty and probably needs all of the condensers  changed out, but is otherwise in good condition. Does anyone have any "SC" scope modules they would like to find a home for?  Thanks,

   Bruce Gentry, KA2IVY


Re: Scopes in nuclear testing - was Re: [TekScopes] Tek 7103 found at auction in NM

Clark Foley
 

To remain on topic, I should mention Tektronix oscilloscope at least once.
Not all of the underground testing was for intrinsically destructive weapons. During the mid and late 1980s, many of the tests were for power supplies; x-ray pulse-power supplies. That is of course a single pulse of x-rays to power a laser. Refer to SDI orbiting laser defense.


Semi OT: Tektronix TX1, TX3, Fluke 183, 185

 

Hello group,

I'm looking for the following for these meters:
- EEPROM dumps.
- A copy of WSTRM software. (WaveStar for Meters)
- Known commands or clues on another Tek multimeter that uses the same format and may be better documented. (The ones I have so far are "!V?", "!S?", "!M?", "!U?", "!K?")

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