Test Equipment Anonymous (TEA) group therapy thread

[Peter_O]

...snip...

How would you mount the pastic strip? One of the fittings is missing, one does not clamp any more.

They used double sided tape on the older HP cases, to attach the aluminium trim strips.
David

A solution too good and simple to get the idea. 

Any tape known, that is thin and does not start to grease and gunk over the years?
3M 9088 ?

[factory]

I thought 4 layers is a norm, also remember reading something about JLCPCB and 2 layer quality.

Can you use fine line style, 2 tracks between legs?
At least internally connected tracks should be ok.

Some consumer boards are also using jumpers quite heavily.
Under zero ohms you could use multiple tracks for sure.

Have you tried artistic freedoms with component positioning?
5 pin singles are also quite adaptive.

I generally don't like tweezers, one moment something usually zaps away.
How about those small manual suction pens, they at least have less spring force.

OK will definitely go with four layer for this one, might change to four layer for the 8 pin counter board for Rev.B too. Display decoder & latch boards will stay as two layer boards for now, as they are quite simple designs.

I've got plenty of time in the evenings to play around with the PCB design, four layers does allow for smaller tracks, which should help. Will also try swapping the 74HCT02 SOIC to single gates. 

I've got very little experience with surface mount stuff, work weren't interested in more modern kit and EOL'd the lab (apart from one job), didn't help that the engineer has an opinion that surface mount stuff isn't worth repairing & didn't want to take the risk of jobs with more modern programmed ICs.

Yes I know about stuff zapping away, the only surface mount board I've built at home in the past was a Velleman kit, good job they included extra trannystors as one vanished never to be seen again, I can't remember using tweezers, not heard of suction pens before, guess I need some help with recommendations here.

David

[factory]

...snip...

.....I thought. Except I could not solder the leads of the new caps to the inner terminals of the old can.... solder just WILL NOT STICK !    No matter what.
Geez... but I thought people DID restuff these old cans eh ?! So how do they do ?!   
Maybe they remove the old terminals, leaving holes in the seal, and just thread the leads of the new caps through these holes... yeah maybe. Could have done that... but didn't think of it. Next time maybe.

I've always completely removed the insides, drilled holes and wired them directly to the terminals on the outside, as the inner connections are aluminium. The thick wire is for the common connection, in this example I didn't enough leave space to reattach the can, ended up gluing it back together.



David

[Vince]

Thanks for that, sounds like a plan !   

The more painful and time consuming I found, is to hack swa the can. impossible to make a perfectly clean and square cut, and it leaves very edges, which take time toi file back into shape.

Since I am thinking of getting a mini lathe at some point, once the garage is built, one more use for it could be to open these cans ?

I mean you stick the can in the chuck, and use a cutting tool, and hey presto in a few seconds you get a perfectly clean and square cut ! 

[factory]

...snip...

How would you mount the pastic strip? One of the fittings is missing, one does not clamp any more.

They used double sided tape on the older HP cases, to attach the aluminium trim strips.
David

A solution too good and simple to get the idea. 

Any tape known, that is thin and does not start to grease and gunk over the years?
3M 9088 ?

Maybe, I don't know, we used a generic tape like this one at work, stuck very well; https://uk.rs-online.com/web/p/double-sided-tapes/0468443


Description is a bit strange, with complete gibberish, "vibrating level switch & PNP trannystor output", did Shango066 write it? 


David

[TERRA Operative]

My TM506/5006 mainframe rescue continues...

All up 3 bays of the 6 test bad... Good thing I have my tester or I would have risked killing an expensive plugin or two...

Anyway, I can get a replacement 2N3055 from Akihabara for a buck each for the high power bay, and I ordered a full compliment of TIP31C and TIP36C transistors for the other bays, so I'll be able to replace them soon and get this mainframe working perfectly again. It cleaned up real nice too.

That is one beast the don't make like they used to and in this application if they are loaded at all 2N3773 might be a better solution.
Just saying.

Nah, unfortunately no 2N3773's off the shelf in Akiba, but Tek specify the 2N3055, so should be fine.

Thanks for that, sounds like a plan !   

The more painful and time consuming I found, is to hack swa the can. impossible to make a perfectly clean and square cut, and it leaves very edges, which take time toi file back into shape.

Since I am thinking of getting a mini lathe at some point, once the garage is built, one more use for it could be to open these cans ?

I mean you stick the can in the chuck, and use a cutting tool, and hey presto in a few seconds you get a perfectly clean and square cut ! 

On my Fluke 332D, I used a pipe cutter (like used for copper pipes) to make a nice neat cut, then I did as factory said and drilled holes to pass wires through the base to the tabs.
Also, as I only had single capacitors (not dual or triple types) I 3D printed a sabot to hold the new capacitor inside the old can securely.
Finally, a wrap in aluminium tape to seal the can closed had it looking great after burnishing the tape to smooth it all down.

[tautech]

My TM506/5006 mainframe rescue continues...

All up 3 bays of the 6 test bad... Good thing I have my tester or I would have risked killing an expensive plugin or two...

Anyway, I can get a replacement 2N3055 from Akihabara for a buck each for the high power bay, and I ordered a full compliment of TIP31C and TIP36C transistors for the other bays, so I'll be able to replace them soon and get this mainframe working perfectly again. It cleaned up real nice too.

That is one beast the don't make like they used to and in this application if they are loaded at all 2N3773 might be a better solution.
Just saying.

Nah, unfortunately no 2N3773's off the shelf in Akiba, but Tek specify the 2N3055, so should be fine.

Motorola and you have a problem....this you should check. Like I said, they no longer make these like they used to.

[TERRA Operative]

Yeah, I saw that. Different producrion process but no part number update...

The parts I will use are Mospec brand.

http://www.mospec.com.tw/pdf/power/2N3055.pdf

[BU508A]

Any tape known, that is thin and does not start to grease and gunk over the years?
3M 9088 ?

How about Kapton tape (NAWTS)?

Example:
https://www.ebay.de/itm/363993075521

[Peter_O]

snip

Maybe, I don't know, we used a generic tape like this one at work, stuck very well; https://uk.rs-online.com/web/p/double-sided-tapes/0468443


Description is a bit strange, with complete gibberish, "vibrating level switch & PNP trannystor output", did Shango066 write it? 


David

Looks reasonable. And as the 3312 is fully transistorized, it might qualify for this tape.   
In case the tape is able to manage the vibration level, the 3312 would gain an amplitude regulation fallback. 

How about Kapton tape (NAWTS)?

Have some here, but it's single sided.

[Robert763]

For those strips if the pins are broken I use 3 small dots of neutral cure RTV. Holds them in place fine but still easy enough to pull off if you need to get to the screws.

Robert.

[langlv]

Please don't laugh !!!
For mounting the damaged plastic trip, I got good results with silicon sealant for construction (also with liquid rubber). It sticks quite well and do not deteriorate as double side tape.
Good luck.

[TERRA Operative]

My TM506/5006 mainframe rescue continues...

All up 3 bays of the 6 test bad... Good thing I have my tester or I would have risked killing an expensive plugin or two...

Anyway, I can get a replacement 2N3055 from Akihabara for a buck each for the high power bay, and I ordered a full compliment of TIP31C and TIP36C transistors for the other bays, so I'll be able to replace them soon and get this mainframe working perfectly again. It cleaned up real nice too.

That is one beast the don't make like they used to and in this application if they are loaded at all 2N3773 might be a better solution.
Just saying.

Nah, unfortunately no 2N3773's off the shelf in Akiba, but Tek specify the 2N3055, so should be fine.

Motorola and you have a problem....this you should check. Like I said, they no longer make these like they used to.

Good news on the Transistor, I just wired it backwards... , I swapped the wires and now that bay works perfectly.

Note to self, take note of the orientation of the panel when you take a reference photo, things are upside down when you take a photo upside down.  

[Vince]

On my Fluke 332D, I used a pipe cutter (like used for copper pipes) to make a nice neat cut, then I did as factory said and drilled holes to pass wires through the base to the tabs.
Also, as I only had single capacitors (not dual or triple types) I 3D printed a sabot to hold the new capacitor inside the old can securely.
Finally, a wrap in aluminium tape to seal the can closed had it looking great after burnishing the tape to smooth it all down.

A pipe cutter hmmm yes, why not... it's cheap enough and does not take a lot of space...

Only drawback is you can't cut the can right above the "shoulder" at the base of the can, should you want to, but still it's a worthwhile option.

OK so with this advice, next can I have to replace, I will have no excuse ! 

[Vince]

QUAD 33 / 303 vintage amplifier restoration

NEED help from the UK !

Trying to finish this project so I can finally put them up for sale.

The 33 preamp is missing a button, an orange one that reads " MONO (right) ".

I can't possibly sell it like this, I need a replacement button.
Problem, they appear to be.. rare.

That specialized  "DADA" website in Germany lists all the 33 buttons for sale but that have been out of stock of 99% of them for 6 months since I started  looking at that site. So I give up. I ordered stuff from them regardless... the 2N5320/22 transistors I need to finish up the 303 power amps... ordered 7 days ago and still nothing in my mail box, and not an e-mail either.. nada. Not impressed. 

Anyway, I googled for this button, and the only place in the world that appears to have the one I need, is this ebay ad :

https://www.ebay.co.uk/itm/125745643583

He sells the complete lot of the 3 orange buttons that the 33 sports.. I only need one of them of course... and the one I need is precisely the one he says is cracked on its side    Luckily not visible in service, and easy enough to superglue.

I am so desperate to get theses amps out the door that I am willing to pay the whooping 12 quids he asks just to get a tiny piece of 50 year old broken plastic 

Problem.... he resides in the UK, in a place by the name of " Bromley ", south London says GoogleMaps, and ships only to the UK ! 
I sent him a message anyway, a week or 10 days ago can't even remember.... no reply 

So.... I need some TEA solidarity from my UK cousins please ! That's my only chance to finish the restoration of this amp.

Guy charges 2.5 quid for UK shipping. So that's 12 + 2.5 = 14.5 Quids shipped to your door... then add 3 or 4 more Quids to ship it back to me in Frog land in a small padded envelope, or not padded... whatever you have on hand.  So about 20 quid for me to get that broken button.... what has the world come to.
I am only doing that because I want these amps out the door and because it looks like I should get my money back and some more, so I see it as an investment rather than throwing money into a pit.


Anyone can help ?!  I would pay you via Paypal. If you don't have an account, I gather that Paypal can transfer you the money anyway. though I have no idea how this would work out i practice neither from my end or yours... so it would easier if you had an account.

Shankew vary moosh !!!   

[factory]

Vince there is a problem with Royal Mail at the moment, their crappy clapped out servers got pwned a few weeks ago and as far as I know they are not taking some international packages at the moment, while they try & clear the backlog.

David

[Vince]

Thanks for the info ! Boy that's my luck !!!   

Still, I can't afford not to buy these buttons, so "you" / someone could still buy them right now, to secure them, and then ship them back to me whenever international shipping is deemed "safe" again.. whenever that might be. Most important is to secure these buttons...

Going to bed, good night TEA... 

[factory]

OK bought them...

David

[Zucca]

in case you would like to play with some ARM® Cortex®-M3 for dirty cheap

https://www.ebay.com/itm/295501508231

[BU508A]

How about Kapton tape (NAWTS)?

Have some here, but it's single sided.

Doublesided Kapton tape is available on Amazon (NAWTS) for example:
https://www.amazon.de/Kapton-Polyimid-Klebeband-doppelseitig-hitzebest%C3%A4ndig/dp/B07QN9SSTN

[Vince]

Morning TEA,

OK bought them...

David

Thanks ! 

PM me your Paypal info with a confirmation of the total amount. I will transfer you the money this evening once I am back home.

[hvontres]

First post here... I seem to have developed a bit of a problem after watching Curious Marc repair a bunch of old hp gear. Coupled with a place up by work that does local pickup on dodgy old test equipment I have fixed up several patients so far. So far mostly just power supply issues. Tonight's rescue was an old HP 8642b. Turned out the only immediate issue were the blown +/- 15V fuses. I will do a more testing over the weekend, but at least the frequency seems to be fairly close:
" alt="" class="bbc_img" />
Since I haven't finished my 10Mhz GPDO yet, I am using the A/B function on my 5316a and the 1pps out of my gps receiver for now.

More to come, espicially my "tower of Power" (4 6253A's , all just had cosmetic issues.)

[oz2cpu]

wow more nixie stuff scored :-)
Fluke 1941A Digital Counter Nixie 1974 5Hz to 40MHz
https://youtu.be/j4QQBje5jRQ

[dl6lr]

This one?:
https://www.thingiverse.com/thing:3057821

Maybe this one fits:
https://www.thingiverse.com/thing:5141182

If not feel free to change to your requirements as the source is included. I did some effort to have the replica the same appearance as the one on my scope. It is more detailed than the one you found.

[Vince]

TEK 7603 PSU RECAP

22H30, I am just finished recapping the PSU after 3 solid hours of painful labour. I hate the construction of '70s scopes with a passion my limited vocabulary would fail to describe.

But it's done.... and I am not rewarded for all my efforts and tenacity in this endeavour : scope doesn't work any more. 

The plusses :

1) Fan starts
2) Power LED lights up.
3) Graticule illumination works.
4) After a few minutes no magic smoke escaped, and no explosions, which means I didn't solder any of the caps backward.

The minuses :

1) Nothing at all shows up on the CRT, it's dead jim.
2) Nothing at all shows up on the CRT, it's dead jim.
3) Nothing at all shows up on the CRT, it's dead jim.


I would throw this thing out the window, but unfortunately it's a single storey house so the thing would most definitely survive. It suffered  much worse damage during shipping yet still worked. So... I guess I must fix it ?


That will be for tomorrow...