Date   

Re: How to troubleshoot a faulty 7B92A?

Thierry Delaitre
 

thank you Dan/Mark. nearly there...

There was no reference voltage . I've therefore replaced U752 (LM741). This has restored the sweep on the interface board, AV, AU (holdoff) and can now see the sweep on TP450

I still have the 7B92A on the vertical slot and cannot see any sweep

I found that Q902 and Q912 were leaky and have replaced both on the output board.

I can now see the sweep for the delayed time base but not for the main timebase (ie horizontal line).

I can see the sweep at TP450 so not sure where things go wrong on the output board

It is not that easy to troubleshoot the output board with the horizontal logic board on top of the interface board

Thanks

Thierry


Re: More fun with avalanche pulsers

 

Thanks :) I stuffed it all into the 5 x 2-1/4 square Minibox, including a 6 ns semirigid charge line.
Displayed 10-90 risetime is just under 400 ps on a 75 ps sampling head.
Flat-top could be flatter but that really hurts the risetime...
I'd need to go to microstrip and leadless (surface-mount) parts to get any more performance. That's another project for another day!
Pics added to avalanche pulser album.


Re: 7A16A high frequency compensation.

unclebanjoman
 

Hi all,
I've just uploaded two screenshots:

https://groups.io/g/TekScopes/photo/262075/4
https://groups.io/g/TekScopes/photo/262075/5

It's my PG506's (+) fast rise output directly coupled to a PM3340 2GHz Philips oscilloscope. High quality, 80 cm RG223/U with Uber-Suhner connectors (BNC to N) cable was used. 10x attenuator was used to keep the PG506's output level over 100 mV.
A nice 632 ps rise time with no aberrations. This implies that the calibration of my 7A16A is practically perfect, as Albert also said

Cheers,
Max


11801, 11801C and CSA803A repair projects

Reginald Beardsley
 

This started as a conversation among @oculus, Jerry Hancock and I. Jerry got an 11801C, @oculus got a CSA803A and I've got a 2nd 11801 which Jerry in a fit of foolishness sold to me ;-) along with an SD-26 with a bad channel that turned out worked perfectly the 2nd time I tested it before shipping it back to Jerry. But it's still causing Jerry trouble. Fortunately, I took photos and can prove it *really* did work correctly in the far left slot of 11801 #1. When I got it and tested it, I wrote on it in pencil, so I know it's the one I got from Jerry and not one of the set of 4x I bought for $$$.

As I was finishing this I realized we really should archive the work on the list. The previous emails don't amount to anything, but at this point it's worth archiving.

Have Fun!
Reg

-----------------------------------------------------------------------------------------------------------------------------------

I've got 11801 #2 on the bench. There is no calibrator output. Interestingly it passes all the diagnostics but they don't seem to run automatically. However, there is a way to jumper those off which I'll need to look up, pull the correct board and check.

I just discovered that there are additional diagnostics windows for each of the blocks across the top of the Utility screen which vary with the subsystem selected on the LHS.

On 11801 #1 setting the trigger to "internal" starts the calibrator verified using a DSO. But it does not on #2 which explains why I couldn't get autoset to work on #2. IIRC I tried running #2 in the stack in the dining room and got error messages from the diagnostics.

The SD-26 I sent back to Jerry, when it came didn't work properly on one channel verified on 11801 #1. Before I sent it back to Jerry I tested it on #1 again and it worked. But Jerry is having problems with it.

I have now verified that the calibrator is getting an input signal, but not producing output. I don't yet know if it is getting power. I hope it's not. That <20 ps source would be pure unobtainium and unrepairable without a wirebonder and an almost unobtainum tunnel diode. One could build a replacement using the same Maxim chip that Leo uses which has a rise time spec of 21 ps. It might well be a bit quicker with a smaller step.

The input to the calibrator is a square wave so it should be possible to make a replacement for the crappy 250 ps rise time calibrator in the 11801C. Should be a very simple board and *very* popular with 11801C owners. I don't know when they changed from the marvelous <20 ps pulser to the 250 ps pulser, but learning that killed my interest in getting a C unless there is a way to put a better calibrator in it.

11801 #1 is equipped with an SD-22, SD-24, SD-26 and SD-32 set and now occupies a place of honor on my very small bench.

On Saturday, March 27, 2021, 01:57:11 PM CDT, Sean Turner <sdturne@q.com> wrote:

#yiv6493947978 #yiv6493947978 -- _filtered {} _filtered {} _filtered {}#yiv6493947978 #yiv6493947978 p.yiv6493947978MsoNormal, #yiv6493947978 li.yiv6493947978MsoNormal, #yiv6493947978 div.yiv6493947978MsoNormal {margin:0in;font-size:11.0pt;font-family:sans-serif;}#yiv6493947978 p.yiv6493947978msonormal, #yiv6493947978 li.yiv6493947978msonormal, #yiv6493947978 div.yiv6493947978msonormal {margin-right:0in;margin-left:0in;font-size:11.0pt;font-family:sans-serif;}#yiv6493947978 p.yiv6493947978msonormal3, #yiv6493947978 li.yiv6493947978msonormal3, #yiv6493947978 div.yiv6493947978msonormal3 {margin-right:0in;margin-left:0in;font-size:11.0pt;font-family:sans-serif;}#yiv6493947978 p.yiv6493947978msonormal41, #yiv6493947978 li.yiv6493947978msonormal41, #yiv6493947978 div.yiv6493947978msonormal41 {margin-right:0in;margin-left:0in;font-size:11.0pt;font-family:sans-serif;}#yiv6493947978 p.yiv6493947978msonormal311, #yiv6493947978 li.yiv6493947978msonormal311, #yiv6493947978 div.yiv6493947978msonormal311 {margin-right:0in;margin-left:0in;font-size:11.0pt;font-family:sans-serif;}#yiv6493947978 span.yiv6493947978EmailStyle34 {font-family:sans-serif;color:windowtext;}#yiv6493947978 .yiv6493947978MsoChpDefault {font-size:10.0pt;} _filtered {}#yiv6493947978 div.yiv6493947978WordSection1 {}#yiv6493947978
I don’t know if they made changes to the self test suite, but this unit goes into an extended diagnostics mode that very definitely tells you what FRUs (field replacement units…fancy euphemism for “we don’t do component level troubleshooting anymore”) may be responsible for each error code. I highly doubt those would be completely wrong, as that would waste the time of the service center people back when this unit was supported. There are *no* errors reported for executive functions or display functions.

 

However, that’s neither here nor there. I’ve now reseated everything, but no dice on clearing any errors.

 

Sean

 

From: Reginald Beardsley <pulaskite@yahoo.com>
Date: Saturday, March 27, 2021 at 12:39
To: Jerry Hancock <jerry@hanler.com>, Sean Turner <sdturne@q.com>
Subject: Re: error codes

 

You're assuming that the error reporting is correct. I'd advise not making that assumption.

There is not enough data to analyze the messages except in a very general way and we know almost nothing about what signals are on what connections.

KISS Pull each board and cable, then replace it. Go to the next board and repeat. Boot system. If errors show up repeat the process. That worked for my 11801 and Jerry's 11801C. It also worked for Jerry for the 11801 I got from him which is now throwing errors. I'll bet that when I do it tomorrow it will be happy again.

My bench is not completely clean, but very close.

BTW the 11801 loses the traces when powered off.



On Saturday, March 27, 2021, 01:25:08 PM CDT, Sean Turner <sdturne@q.com> wrote:

 

 

Yes, I see that now. However, there are no faults in those areas. All the errors point towards the acquisition module and possibly the strobe driver. I did figure out the acquisition module removal. I re-seated everything in the acquisition module; unfortunately this didn’t clear any of those faults.

 

Funny enough, the prior owner never cleared their data, so there are a bunch of stored traces available.

 

Sean

 

From: Reginald Beardsley <pulaskite@yahoo.com>
Date: Saturday, March 27, 2021 at 12:09
To: Jerry Hancock <jerry@hanler.com>, Sean Turner <sdturne@q.com>
Subject: Re: error codes

 


Yes, there are boards to pull. Look at p 6-14. The A17, A18, A14 & A15 all plug into the A13 motherboard. This is clearly documented on pp 6-50 to 6-56.

The 11801 has 2 memory boards instead of just one.

On Saturday, March 27, 2021, 12:47:48 PM CDT, Sean Turner <sdturne@q.com> wrote:

 

 

So there’s really no cards to pull, per se. Everything is connected with ribbon cables. My hypothesis is the problem lies in the acquisition module based on the self test results. I am working out how to remove it, as the manual isn’t perfectly clear on the matter. It (https://w140.com/tekwiki/images/d/de/070-8780-01.pdf) speaks of removing two Torx screws that hold a frame section in, but I can’t find any diagrams that show where these screws are.

 

Tomorrow is fine by me.

 

Sean

 

From: Reginald Beardsley <pulaskite@yahoo.com>
Date: Saturday, March 27, 2021 at 10:13
To: Jerry Hancock <jerry@hanler.com>, Sean Turner <sdturne@q.com>
Subject: Re: error codes

 


You don't need any sampling heads installed. I'm doing a CS class from 2-3 pm EST so tomorrow would be the soonest I could do it. I think Jerry is busy today also.

Did you pull all the cards from the backplane? IIRC they need to be in a specific order which is shown in the manual. It's quite a chore to reseat everything.

IIRC I was not willing to dig as far as the head connector board because of the huge PITA it presented.

I am quite amazed at how broken the autotools configuration for gnuplot-5.4.1 is trying to build on Ubuntu 14.04 LTS. God what a mess. It's depending on pkg-config which is broken. I think that imake has risen from the dead with a new name.

On Saturday, March 27, 2021, 10:55:55 AM CDT, Sean Turner <sdturne@q.com> wrote:

 

 

Yeah, that sounds good. Let’s do that once I get that sampling head you’re sending me, so I can rule out the thing freaking out because there’s no head present.

 

I’ve reseated all the connectors I can get to (seems to be mostly ribbon cables so far), but I haven’t yet figured out how to get to into the plug in bay…I will work that problem today.

 

Sean

 

From: Reginald Beardsley <pulaskite@yahoo.com>
Date: Saturday, March 27, 2021 at 08:32
To: Sean Turner <sdturne@q.com>, Jerry Hancock <jerry@hanler.com>
Subject: Re: error codes

 


The T3314 is most likely bad connection. At least that is what Jerry Hancock found recently with his 11801C. I had similar experience. I had to completely reseat my 11801 twice to clear the errors. I should note the errors were not shown in the photo on ebay. Just the NVRAM error. These beasts do not like traveling. I think they are probably all bad connections.

I'd suggest Deoxit, but getting at the backplane would be such an ordeal that just repeated reseating seems more reasonable. My first 11801 has been completely reliable once I had it working.

I'd like to suggest that the 3 of us get on the phone together to discuss. I suspect that among us we can deduce the answers.

I can drag my spare 11801 in once I clean off my bench and work on getting it going. It worked when Jerry foolishly sold it to me, but did not when it finally got here.

On Friday, March 26, 2021, 10:00:07 PM CDT, Sean Turner <sdturne@q.com> wrote:

 

 

These are the codes I pulled out of the selftest:

 

|
Subsystem
|
Block
|
Area
|
Routine
|
Index
|
|
Time Base
|
M/F I/F
|
Strobe Gate
|
Acq 1
|
T3314
|
|
Main Acq
|
Acq 1
|
Signal Path
|
Strobes
|
m1422
|
|
Main Acq
|
Acq 1
|
Signal Path
|
Signal Path A
|
m1461
|
|
Main Acq
|
Acq 1
|
Measurement
|
Filter A
|
m1521
|
|
Main Acq
|
Acq 1
|
Measurement
|
A->B B->A
|
m1541
|


Photo 5 ns/div, 1 v/div into 50 ohms. Reflections are minimal with the PTFE semi-rigid coax line. updated #photo-notice

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

The following photos have been updated in the Avalanche pulser album of the TekScopes@groups.io group.

By: Charles <charlesmorris800@...>


Re: How to explain how negative feedback lowers noise?

Tom Lee
 

Hi Ted,

I recommend continuing to read papers beyond those from 1923. It's hard to do better than to read Black's own 1934 paper (January issue of bstj, also available at archive.org, as well as worldradiohistory.com). Far from being a "canard", you will see from Black's own pen what the motivations for negative feedback were. If you still wish to refute him, you'll have to reanimate his corpse. The 1923 paper you cite enumerates many problems facing transcontinental telephony at that early time, but if you examine the list carefully, you'll see that every one of those problems is solvable, if clumsily, by open-loop means, with the conspicuous exception of distortion.

It's also important to recognize that the 1923 paper predates the advent of carrier-based telephony by several years (the author is still talking about loading coils!). Once multiple, carrier-modulated telephone signals were to share a circuit, the problem of distortion became the showstopper. Negative feedback solved that problem (and a host of others conveniently as well). Without negative feedback, AT&T could not have made transcontinental telephony practical.

-- Cheers,
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 3/27/2021 09:39, Ted Rook wrote:
While as a self-taught amateur physicist I hesitate to challenge a university professor but if
my understanding is correct (and it is often not so) the argument that the purpose of the
introduction of NFB was to reduce distortion should be viewed as a canard that belongs in
the realms of imagination where high-end audio fanatics can often be found.

Some insight into the background of problems with long distance (but not transcontinental)
telephony before the development of the negative feedback amplifier is provided in Bell
System Technical Journal 1923, January, author Clark, title "Telephone Transmission over
long cable circuits" which is to be found among other places as a free download at the
Internet Archive https://archive.org/details/bstj2-1-67

The information presented makes it clear that the idea of reduction of distortion as the driver
of development of the negative feedback amplifier fails to recognize difficulties of a more
fundamental nature that inhibited development of transcontinental telephony and demanded
a solution, which was eventually delivered by the new invention. In addition to solution of the
fundamental problem of gain instability under hostile conditions, among the other benefits
delivered by the negative feedback amplifier were improvements to frequency response,
input and output impedances and also harmonic distortion.

The article is a fascinating insight into the very early days of long distance telephony and the
content is mostly non-mathematical.

Ted Rook


On 26 Mar 2021 at 2:03, Tom Lee wrote:

The reason it didn't happen for electronics until 1927 is that the preoccupation until that point was getting more gain per tube. Positive feedback (Armstrong's regenerative amplifier) was the magic elixir that had enabled the age of electronics to begin, around WWI. Early tubes struggled to achieve voltage gains of five. The first generation of EEs was thus trained to think of getting enough gain as the main problem.

It wasn't until AT&T ran into troubles with transcontinental telephony that someone had to invent a fix for a different problem: distortion. A cascade of hundreds of repeaters demanded individual amplifiers of unprecedented linearity. This necessity was the mother of negative feedback.

Black's invention required quite a change in thinking. Now he was recommending "throwing away" precious gain in exchange for reduced distortion. This went against the training of a generation of EEs. Given that, I'm not surprised negative feedback took that long to get formalized.

Although you are absolutely right that a basic intuitive notion of negative feedback was appreciated long before electronics came along, Black was the first in history to understand explicitly that excess gain could be used as currency to pay for reductions in distortion. It is as subtle a notion as it is powerful.

The very first mathematical treatment of negative feedback was by Maxwell himself, but his analysis was limited to understanding why speed governors for steam engines could go unstable. Until technology ran into the need for exquisite precision in control, there was no need for Black to come along.

Cheers
Tom

Sent from an iThing; please excuse the terseness and typos

On Mar 25, 2021, at 23:14, "Ed Breya via groups.io" <edbreya=yahoo.com@groups.io> wrote
I don't know about this history, but am surprised that this didn't happen until 1929, well into the electronics era. Surely the concept of negative feedback in control systems has existed in nature, throughout human history, and in industry - at least since the steam era - look at the fly-ball governor, for example. Maybe in electronics, it wasn't so obvious, although it already existed in some forms, say for instance, with degenerative feedback in a vacuum tube, stabilizing the bias with the cathode resistor. People were driving horses, trains, planes, and automobiles successfully before 1929, using that PID controller in the skull.

Ed










Re: Repair of Set Screw Attachment for Tek-made VAR Pots

widgethunter <tubesnthings@...>
 

Nice! Been looking for a fix for the 1A4.Wouldn't mind getting some.Bernd Schroder

-----Original Message-----
From: Jim Adney <jadney@vwtype3.org>
To: TekScopes@groups.io
Sent: Fri, Mar 26, 2021 2:20 pm
Subject: [TekScopes] Repair of Set Screw Attachment for Tek-made VAR Pots

Quite a few years ago, I came across my first broken Tek-made VAR pot, the grey plastic ones. The plastic had broken near where the shaft enters, so that the set screw could no longer bind tightly to the shaft. As spares seemed like they might be hard to find, I came up with a more permanent solution, which you can see here:

https://groups.io/g/TekScopes/photo/262268/1 and also the following photo

These rings are tapped 4-40, the same as the OE set screws, but the ring encircles the cross-shaped portion of the pot allowing plenty of tightening of the set screw. The new, longer, set screw passes thru the original 4-40 hole, but does not use those threads, so this repair will fix a pot with stripped threads or fractured plastic there.

I made a supply of these for myself and have used a half dozen of them on various 3 series plugins. They take up almost no more room than the original pot, so I've yet to encounter a place where this wasn't a quick and neat fix. I have a small supply of these if anyone needs one, or feel free to copy the idea and make your own.


Re: How to explain how negative feedback lowers noise?

Ted Rook
 

While as a self-taught amateur physicist I hesitate to challenge a university professor but if
my understanding is correct (and it is often not so) the argument that the purpose of the
introduction of NFB was to reduce distortion should be viewed as a canard that belongs in
the realms of imagination where high-end audio fanatics can often be found.

Some insight into the background of problems with long distance (but not transcontinental)
telephony before the development of the negative feedback amplifier is provided in Bell
System Technical Journal 1923, January, author Clark, title "Telephone Transmission over
long cable circuits" which is to be found among other places as a free download at the
Internet Archive https://archive.org/details/bstj2-1-67

The information presented makes it clear that the idea of reduction of distortion as the driver
of development of the negative feedback amplifier fails to recognize difficulties of a more
fundamental nature that inhibited development of transcontinental telephony and demanded
a solution, which was eventually delivered by the new invention. In addition to solution of the
fundamental problem of gain instability under hostile conditions, among the other benefits
delivered by the negative feedback amplifier were improvements to frequency response,
input and output impedances and also harmonic distortion.

The article is a fascinating insight into the very early days of long distance telephony and the
content is mostly non-mathematical.

Ted Rook

On 26 Mar 2021 at 2:03, Tom Lee wrote:

The reason it didn't happen for electronics until 1927 is that the preoccupation until that point was getting more gain per tube. Positive feedback (Armstrong's regenerative amplifier) was the magic elixir that had enabled the age of electronics to begin, around WWI. Early tubes struggled to achieve voltage gains of five. The first generation of EEs was thus trained to think of getting enough gain as the main problem.

It wasn't until AT&T ran into troubles with transcontinental telephony that someone had to invent a fix for a different problem: distortion. A cascade of hundreds of repeaters demanded individual amplifiers of unprecedented linearity. This necessity was the mother of negative feedback.

Black's invention required quite a change in thinking. Now he was recommending "throwing away" precious gain in exchange for reduced distortion. This went against the training of a generation of EEs. Given that, I'm not surprised negative feedback took that long to get formalized.

Although you are absolutely right that a basic intuitive notion of negative feedback was appreciated long before electronics came along, Black was the first in history to understand explicitly that excess gain could be used as currency to pay for reductions in distortion. It is as subtle a notion as it is powerful.

The very first mathematical treatment of negative feedback was by Maxwell himself, but his analysis was limited to understanding why speed governors for steam engines could go unstable. Until technology ran into the need for exquisite precision in control, there was no need for Black to come along.

Cheers
Tom

Sent from an iThing; please excuse the terseness and typos

On Mar 25, 2021, at 23:14, "Ed Breya via groups.io" <edbreya=yahoo.com@groups.io> wrote
I don't know about this history, but am surprised that this didn't happen until 1929, well into the electronics era. Surely the concept of negative feedback in control systems has existed in nature, throughout human history, and in industry - at least since the steam era - look at the fly-ball governor, for example. Maybe in electronics, it wasn't so obvious, although it already existed in some forms, say for instance, with degenerative feedback in a vacuum tube, stabilizing the bias with the cathode resistor. People were driving horses, trains, planes, and automobiles successfully before 1929, using that PID controller in the skull.

Ed








Re: Persuading a 7S12 to play nice with a 7934.

Albert Otten
 

P600 connects the base of the 2N2907A either to ground or to the collectors of
the transistors which perform the (B7 XOR A16) function.
Thanks a lot Richard! It really looked as if the third pcb pin was isolated from the rest and was only there to keep the jumper save in non-gnd position. So I simply left the jumper out when trying things! This also means that interdot blanking enabled/disabled is not the correct description for the P600 positions. It's always enabled (except when left out) and enables/disables B7/A16 function you mentioned.
Now I put P600 in the non-gnd position and tried things again. And yes, now I get interdot blanking leakage in the 7A26 trace. I added a photo to your album.
As I said, my board has no P600. The collectors of the XOR transistors and the base of the 2N2907A are directly connected by a trace on the non-component side of the board.
Where is P600 located on your board? I don't see it depicted on the board illustrations of any of the manuals I have looked at.
For this I also added a photo.

Albert


Re: Persuading a 7S12 to play nice with a 7934.

Richard Steedman
 

Thanks for your insight on this Albert.

By coincidence, a paper copy of the 7S12 manual which I purchased on eBay a while back arrived today, dated June 1986. So now I have yet another reference to consult. It shows the same arrangement as the BAMA manual - P600 connects the base of the 2N2907A either to ground or to the collectors of the transistors which perform the (B7 XOR A16) function.

It's strange. With a DMM I could not find a connection of 2N2907A-base to any other component in the neighborhood or a A/B contact. But then the pair of NPN transistors with their bases to the B7 and A16 inputs would be useless. Do I overlook something?

You didn't accidentally have your P600 set such that the link between the NPNs and the 2N2907A-base was open?

As I said, my board has no P600. The collectors of the XOR transistors and the base of the 2N2907A are directly connected by a trace on the non-component side of the board. Where is P600 located on your board? I don't see it depicted on the board illustrations of any of the manuals I have looked at.

This circuit seems to have undergone many revisions over the years - perhaps reflecting issues encountered with newer generation mainframes. I share your unease about reducing the pullup resistor to 6kΩ. My other thought was to put the B7 input through an opto-isolator to get a proper 0V/5V swing and see if that cleans things up. This is easily done by lifting one end of R691 (the 430Ω resistor) off the board.

Richard


Re: 2440 and 2465B battery/ram replacement

Bob Albert
 

Chuck, where are you?  I am in Los Angeles and would like to find someone who is willing to get my Tek 2440 working.  Maybe that's not you.
The history is that when I got it, it worked but would not hold settings on power off.  I decided it must need new NVRAM modules and swapped in some I got from China on ebay.  Now the scope doesn't work at all.  I swapped one module back but still no joy.  It turns on but the display is messed up and it won't respond to any controls.
I would like to find someone who is smarter than I who is willing to correct my mistakes and get the scope operational again.  If you can assist in any way I would appreciate it.  I am willing to pay a reasonable amount, as well.
Thanks, Bob

On Friday, March 26, 2021, 07:24:54 PM PDT, Chuck Harris <cfharris@erols.com> wrote:

Hi Mark,

I am always willing to do the work.  Contact me
off group.

-Chuck Harris


On Fri, 26 Mar 2021 15:45:26 -0700 "Mark Vincent"
<orangeglowaudio@gmail.com> wrote:
Reinhard,

      I have seen this site. It is great. I do NOT have a programmer
or access to one. I do NOT have ANY TM500/5000 anything. I do not
know anyone locally that has these. This is why I asked here to see
if anyone will do the work.

Mark





Re: Repair of Set Screw Attachment for Tek-made VAR Pots

Dave Wise
 

You ought to upload the article to TekWiki at w140.com .


Dave Wise

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Wayne via groups.io <WAYNECL=AOL.COM@groups.io>
Sent: Friday, March 26, 2021 2:43 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Repair of Set Screw Attachment for Tek-made VAR Pots

Nice solution! Haven't run across a need for one yet, but if I do, the lathe is right there waiting! Thanks for the post and the nice pictures!


Re: 2440 and 2465B battery/ram replacement

Chuck Harris <cfharris@...>
 

Hi Mark,

I am always willing to do the work. Contact me
off group.

-Chuck Harris


On Fri, 26 Mar 2021 15:45:26 -0700 "Mark Vincent"
<orangeglowaudio@gmail.com> wrote:
Reinhard,

I have seen this site. It is great. I do NOT have a programmer
or access to one. I do NOT have ANY TM500/5000 anything. I do not
know anyone locally that has these. This is why I asked here to see
if anyone will do the work.

Mark





Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Dave Daniel
 

I’ll check that. It sounds like the culprit. Thanks

DaveD

On Mar 26, 2021, at 19:44, Larry McDavid <lmcdavid@lmceng.com> wrote:

Be careful to include the final hyphen character in the Google Drive link; that final character is often not in the active email link.LarrySent via the Samsung Galaxy S10
-------- Original message --------From: Dave Seiter <d.seiter@att.net> Date: 3/26/21 4:34 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful? I just tried the "drive/google" link from this email and it worked fine.-Dave On Friday, March 26, 2021, 03:14:22 PM PDT, Dave Daniel <kc0wjn@gmail.com> wrote: Can someone point me to the correct links for the documentation? Both links below are unreachable.ThanksDaveDOn 12/31/2020 2:27 PM, Jared Cabot via groups.io wrote:> Hi all,>> I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around.> I updated the design somewhat and designed it for simplified construction (Not a single wire to strip and solder!) and I thought someone here might be interested in taking a look or even building one themselves.> Here's a link to the youtube video:> https://www.youtube.com/watch?v=Afwqtc6Fxd4>> And here's a link to the google drive with all the gerbers and schematics and stuff. I went so far as to rewrite the manual with the alterations and corrections included.> https://drive.google.com/drive/folders/1yj52Z_BtGZ7Q9BB2jS9Lf2Uz39turS4->> Direct link to the new manual:> https://drive.google.com/file/d/1iqpcqheb01qMioQwcUhyWv6A37v2HPro/view?usp=sharing>> Let me know what you think, and let me know if you see any errors that need correcting. :)>> Regards> Jared.>>> >>>-- This email has been checked for viruses by Avast antivirus software.https://www.avast.com/antivirus




Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Larry McDavid
 

Be careful to include the final hyphen character in the Google Drive link; that final character is often not in the active email link.LarrySent via the Samsung Galaxy S10

-------- Original message --------From: Dave Seiter <d.seiter@att.net> Date: 3/26/21 4:34 PM (GMT-08:00) To: TekScopes@groups.io Subject: Re: [TekScopes] I built a TM500 mainframe tester, and updated the design. Someone might find this useful? I just tried the "drive/google" link from this email and it worked fine.-Dave    On Friday, March 26, 2021, 03:14:22 PM PDT, Dave Daniel <kc0wjn@gmail.com> wrote:  Can someone point me to the correct links for the documentation? Both links below are unreachable.ThanksDaveDOn 12/31/2020 2:27 PM, Jared Cabot via groups.io wrote:> Hi all,>> I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around.> I updated the design somewhat and designed it for simplified construction (Not a single wire to strip and solder!) and I thought someone here might be interested in taking a look or even building one themselves.> Here's a link to the youtube video:> https://www.youtube.com/watch?v=Afwqtc6Fxd4>> And here's a link to the google drive with all the gerbers and schematics and stuff. I went so far as to rewrite the manual with the alterations and corrections included.> https://drive.google.com/drive/folders/1yj52Z_BtGZ7Q9BB2jS9Lf2Uz39turS4->> Direct link to the new manual:> https://drive.google.com/file/d/1iqpcqheb01qMioQwcUhyWv6A37v2HPro/view?usp=sharing>> Let me know what you think, and let me know if you see any errors that need correcting. :)>> Regards> Jared.>>> >>>-- This email has been checked for viruses by Avast antivirus software.https://www.avast.com/antivirus


Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Dave Daniel
 

Thanks.

On Mar 26, 2021, at 19:33, Dave Seiter <d.seiter@att.net> wrote:

I just tried the "drive/google" link from this email and it worked fine.
-Dave
On Friday, March 26, 2021, 03:14:22 PM PDT, Dave Daniel <kc0wjn@gmail.com> wrote:

Can someone point me to the correct links for the documentation? Both
links below are unreachable.

Thanks

DaveD


On 12/31/2020 2:27 PM, Jared Cabot via groups.io wrote:
Hi all,

I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around.
I updated the design somewhat and designed it for simplified construction (Not a single wire to strip and solder!) and I thought someone here might be interested in taking a look or even building one themselves.
Here's a link to the youtube video:
https://www.youtube.com/watch?v=Afwqtc6Fxd4

And here's a link to the google drive with all the gerbers and schematics and stuff. I went so far as to rewrite the manual with the alterations and corrections included.
https://drive.google.com/drive/folders/1yj52Z_BtGZ7Q9BB2jS9Lf2Uz39turS4-

Direct link to the new manual:
https://drive.google.com/file/d/1iqpcqheb01qMioQwcUhyWv6A37v2HPro/view?usp=sharing

Let me know what you think, and let me know if you see any errors that need correcting. :)

Regards
Jared.






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This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus












Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Dave Seiter
 

I just tried the "drive/google" link from this email and it worked fine.
-Dave

On Friday, March 26, 2021, 03:14:22 PM PDT, Dave Daniel <kc0wjn@gmail.com> wrote:

Can someone point me to the correct links for the documentation? Both
links below are unreachable.

Thanks

DaveD


On 12/31/2020 2:27 PM, Jared Cabot via groups.io wrote:
Hi all,

I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around.
I updated the design somewhat and designed it for simplified construction (Not a single wire to strip and solder!) and I thought someone here might be interested in taking a look or even building one themselves.
Here's a link to the youtube video:
https://www.youtube.com/watch?v=Afwqtc6Fxd4

And here's a link to the google drive with all the gerbers and schematics and stuff. I went so far as to rewrite the manual with the alterations and corrections included.
https://drive.google.com/drive/folders/1yj52Z_BtGZ7Q9BB2jS9Lf2Uz39turS4-

Direct link to the new manual:
https://drive.google.com/file/d/1iqpcqheb01qMioQwcUhyWv6A37v2HPro/view?usp=sharing

Let me know what you think, and let me know if you see any errors that need correcting. :)

Regards
Jared.






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This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: 2440 and 2465B battery/ram replacement

Mark Vincent
 

Reinhard,

I have seen this site. It is great. I do NOT have a programmer or access to one. I do NOT have ANY TM500/5000 anything. I do not know anyone locally that has these. This is why I asked here to see if anyone will do the work.

Mark


Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?

Dave Daniel
 

Can someone point me to the correct links for the documentation? Both links below are unreachable.

Thanks

DaveD

On 12/31/2020 2:27 PM, Jared Cabot via groups.io wrote:
Hi all,

I have been accumulating TM500 modules and mainframes for a little while, so I recently finished building an 067-1201-99 TM500 mainframe tester from the Tek construction notes floating around.
I updated the design somewhat and designed it for simplified construction (Not a single wire to strip and solder!) and I thought someone here might be interested in taking a look or even building one themselves.
Here's a link to the youtube video:
https://www.youtube.com/watch?v=Afwqtc6Fxd4

And here's a link to the google drive with all the gerbers and schematics and stuff. I went so far as to rewrite the manual with the alterations and corrections included.
https://drive.google.com/drive/folders/1yj52Z_BtGZ7Q9BB2jS9Lf2Uz39turS4-

Direct link to the new manual:
https://drive.google.com/file/d/1iqpcqheb01qMioQwcUhyWv6A37v2HPro/view?usp=sharing

Let me know what you think, and let me know if you see any errors that need correcting. :)

Regards
Jared.




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https://www.avast.com/antivirus


Re: Repair of Set Screw Attachment for Tek-made VAR Pots

Paul Amaranth
 

Quite an elegant solution!

Paul

On Fri, Mar 26, 2021 at 02:20:11PM -0700, Jim Adney wrote:
Quite a few years ago, I came across my first broken Tek-made VAR pot, the grey plastic ones. The plastic had broken near where the shaft enters, so that the set screw could no longer bind tightly to the shaft. As spares seemed like they might be hard to find, I came up with a more permanent solution, which you can see here:

https://groups.io/g/TekScopes/photo/262268/1 and also the following photo

These rings are tapped 4-40, the same as the OE set screws, but the ring encircles the cross-shaped portion of the pot allowing plenty of tightening of the set screw. The new, longer, set screw passes thru the original 4-40 hole, but does not use those threads, so this repair will fix a pot with stripped threads or fractured plastic there.

I made a supply of these for myself and have used a half dozen of them on various 3 series plugins. They take up almost no more room than the original pot, so I've yet to encounter a place where this wasn't a quick and neat fix. I have a small supply of these if anyone needs one, or feel free to copy the idea and make your own.
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@AuroraGrp.Com | Unix/Linux - We don't do windows

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