Test Equipment Anonymous (TEA) group therapy thread

[bd139]

med: it's killing me seeing all those nice era teks. I may end up with a new side table one day 

Yes, just keep going! I never came across the Telequipment/Tek D755 model, so I had to look it up https://w140.com/tekwiki/wiki/Telequipment_D755

It is interesting to see that such fairly sophisticated oscilloscopes were produced after Tektronix had taken over Telequipment. I always thought that the Telequipment models were simpler than the Tektronix-branded ones;  primarily targeting the radio/TV repair shops and general service markets.

Cheers,

THDplusN_bad

Yeah this one is fairly nice. They do a larger counterpart, the D83 which I have owned before and fought with partially successfully and then got tired of the sight of.

Couple of posts about that. I had to break two D83 chassis' in half to get a good top and a good bottom half 

https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1566493/#msg1566493

[tautech]

Yeah don't fancy that  . Think I'll find some surgical forcep scissor things at a hamfest if I need to do any surgery on that sort of part and try and snip it.

D755 update. The fuckity display is due to a dodgy 2M2 trimpot as previously mentioned. I stuffed a DMM across it and found that the potential was only 105 volts. That means the worst case dissipation is about 5mW which is bugger all so ordered some 2M2 Piher 15mm ones rated to 0.25W and 200V. Will see if that does the job. If not it's further HT debugging fun 

Picture of the wee bastard:



Part source:

https://www.ebay.co.uk/itm/321384101191

No chance of reviving it with a swim in IPA or Deoxit and a good workout ?

[bd139]

Possibly but it's got a resistance curve that looks like the following chart and some of its brothers and sisters have started growing tentacles. Figured it's not worth digging it out and cleaning it...

[tautech]

Possibly but it's got a resistance curve that looks like the following chart and some of its brothers and sisters have started growing tentacles. Figured it's not worth digging it out and cleaning it...

Hmm maybe not then. I found those sealed trimmers pretty good in my D83 and any that did give hicups were easily fixed with a little run around the block exercise. 

[med6753]

med: it's killing me seeing all those nice era teks. I may end up with a new side table one day 

Shall I tempt you some more? 

(And notice not one 400 series in sight. I can post them too if you're still feeling lonely)

[cyclin_al]

This is the page to muster all our 3478As...

I'm waiting for page 34401 ...

Dang, I missed it for being 10 pages behind ... 3468A.  Next chance for me is 3610A.  I guess I better get the camera out today before its too late...

[factory]

Just fried my Rigol DM3058E.

End of message. Carry on.

Found you a 34401A you can buy to replace it  eBay auction: #143981804612 same seller seems to have a rough Solartron too.

He'll just have to stock up on 34410a and 7150 - there are plenty at Ramco next week

Already bookmarked 

More interestingly, what did he do to fry it?

As it would seem, if you have a HV source and it's still set to 2kV when you turn it on, it should not be connected to a DM3058E. Who knew.

Maybe an AVO 8 with the 2.5kV or 3kV range would be more useful, or one of these early digital voltmeters from AVO, Solartron or Advance, all have a 2kV DC range.



If you need something rated for higher voltage than 3kV then maybe one of these instead. 


David

[artag]

Gonna fix my Keithley 2000 DVM buttons ..

[bd139]

med: it's killing me seeing all those nice era teks. I may end up with a new side table one day 

Shall I tempt you some more? 

(And notice not one 400 series in sight. I can post them too if you're still feeling lonely)

That’s quite enough Tek to keep me going for a few days now 

[ch_scr]

Gonna fix my Keithley 2000 DVM buttons ..

Really? I just tape little specks of aluminium tape in there. Or just toss a piece of aluminium paper from a pack of cigarettes al foil in there if it's a tv remote and I'm in a hurry.
Edit: Just the other day I had a K2000 with horrible buttons. Gave the gold contacts and the rubber domes a good wipe with cotton ear buds soaked in "Teslanol Oszillin". To my surprise they were good as new. Does not work that way with tv remotes.

[factory]

Another quick teardown from the stuff I acquired at the weekend, this time a mystery control panel (not TEA) from Cossor made for the military, as it was only a couple of £'s it followed me home.


It's mostly a bunch of selector switches and a couple of small displays, the back has a few multi-way connectors. The only switches that have 0-9 are the upper/lower height ones on the right.


Inside and I soon realised the all the switches & buttons had lamps fitted, in the back of the case is a circuit board with a few rows of diodes, all connected with the usual mass of pink wiring.




Looking up the part number on the lamps I found they require 5V and about 3A to run them all, OK about 2.5A as some are blown.


Not much to see in the self contained emergency indicator panel.


David

[beanflying]

Another quick teardown from the stuff I acquired at the weekend, this time a mystery control panel (not TEA) from Cossor made for the military, as it was only a couple of £'s it followed me home.
..
David

All I see is lots of rotary Decade Resistance and Capacitance boxes in your future life or the base for a Coffee TEA Table

[bd139]

Hey something I know what it is for once.  It’s an IFF unit test fixture. I designed the replacement of its replacement 

To note the replacement was 95% software.

[factory]

Another quick teardown from the stuff I acquired at the weekend, this time a mystery control panel (not TEA) from Cossor made for the military, as it was only a couple of £'s it followed me home.
..
David

All I see is lots of rotary Decade Resistance and Capacitance boxes in your future life or the base for a Coffee TEA Table

Yes it has to be one of the most useless items I've bought, there is only enough rotary switches (6) for one decade box, the others are strange thing with a couple numbers/letters, 0-7 & T and one that only has even numbers. I forgot to mention the seven miniature projection displays.

Hey something I know what it is for once.  It’s an IFF unit test fixture. I designed the replacement of its replacement 

To note the replacement was 95% software.

Thanks, I was wondering what the heck it was once used for. 

David

[bd139]

Usage would be for testing commercial IFF transponders. Nothing military as it’s missing mode 4/5/S despite being MoD issued which is weird. it’s also rather old. 60s / 70s I reckon. Any date codes?

The reason the wheels are 0-7 is because it uses octal encoding for the transponder codes. Annoying as if you knew that at the start it’d be a big no for decade boxes. Surprisingly up to date as half the stuff still uses mode C if I remember correctly (probably changed in the 20 years or so since I went near it).

Edit: actually age might be why there is no mode 4/5. Not sure when that was introduced.

[artag]

Edit: Just the other day I had a K2000 with horrible buttons. Gave the gold contacts and the rubber domes a good wipe with cotton ear buds soaked in "Teslanol Oszillin". To my surprise they were good as new. Does not work that way with tv remotes.

Have tried various methods on other switches with no great success, so I was glad to find some actual conductive pads. I think a soft pad should make a better contact than a harder one, even if it does wear quicker.

But thanks for the suggestion - I shall certainly try cleaning before replacing them. Maybe the keithley parts are better quality than the devices I've tried to repair in the past.
 

[ch_scr]

Edit: Just the other day I had a K2000 with horrible buttons. Gave the gold contacts and the rubber domes a good wipe with cotton ear buds soaked in "Teslanol Oszillin". To my surprise they were good as new. Does not work that way with tv remotes.

Have tried various methods on other switches with no great success, so I was glad to find some actual conductive pads. I think a soft pad should make a better contact than a harder one, even if it does wear quicker.

But thanks for the suggestion - I shall certainly try cleaning before replacing them. Maybe the keithley parts are better quality than the devices I've tried to repair in the past.
 

I have multiple ex-tv-repairmen as colleagues and they repair every tv remote with "lazy" buttons just by putting al foil/ al tape in there. The "cigarettes pack al paper" thing propably dates back to when everyone still smoked... They discouraged me to even try graphite paint because it was tried and works for a while but wears pretty fast.

Edit: I literally was so impressed by the K2000 cleaning result I tried the exact same thing on my stereo remote a day later. No cigar. Ended up putting little specks of al tape on the black rubber domes and it's good as new.

Edit#2: I'm talking "aluminium adhesive tape" here, the kind a plumber would use on joints of pipe thermal insulation.

[factory]

Usage would be for testing commercial IFF transponders. Nothing military as it’s missing mode 4/5/S despite being MoD issued which is weird. it’s also rather old. 60s / 70s I reckon. Any date codes?

The reason the wheels are 0-7 is because it uses octal encoding for the transponder codes. Annoying as if you knew that at the start it’d be a big no for decade boxes. Surprisingly up to date as half the stuff still uses mode C if I remember correctly (probably changed in the 20 years or so since I went near it).

Edit: actually age might be why there is no mode 4/5. Not sure when that was introduced.

I'll have another look at the weekend but I can't see any date codes in any of the pictures I took.
I did note a lot of switches were set to T in the listing (they are a bit on the small side for making decade boxes too), was it worth the £2.20 I paid? Mouser want a fair bit for just the lamps: https://www.mouser.co.uk/ProductDetail/VCC/685?qs=%252BE2FUV3UlmzjVQlRnsSH%2Fw==

Maybe I'll spend a bit of time one day trying to trace out where the projection displays are connected to and make it do something useful.

David

[bd139]

I’d have been chuffed for that for £2.20 

Yeah couldn’t see anything useful. The serial numbers are all surrogate codes so not useful without their ERP/asset system to look them up. No metadata encoded for security reasons.

Edit: flash back of happy days seeing no daylight at all, slaving away with a Mars bar and a max pak tub of subsidised caffeinated muck on a rotten NT box on an air gapped network with no humans around. I may have slept a couple of times, probably due to the lack of airflow. I miss that kind of lack of excitement these days 

[Cerebus]

Looks like those OXCOs will be with me soon - ordered on Friday at 8:30 pm, "Arrived at Destination Hub" in the UK a little before 8pm this evening. So yeah, we're now getting stuff from China faster than we're getting it from the other end of the country.

Hmm, anyone interested in a real Chinese food delivery service? 

[bd139]

Yes mine arrived in only 6 days end to end. I think it's the seller as my JLCPCB order has entered the 4px void for the last 5 days now 

[BU508A]

I have multiple ex-tv-repairmen as colleagues and they repair every tv remote with "lazy" buttons just by putting al foil/ al tape in there. The "cigarettes pack al paper" thing propably dates back to when everyone still smoked... They discouraged me to even try graphite paint because it was tried and works for a while but wears pretty fast.

Edit: I literally was so impressed by the K2000 cleaning result I tried the exact same thing on my stereo remote a day later. No cigar. Ended up putting little specks of al tape on the black rubber domes and it's good as new.

Edit#2: I'm talking "aluminium adhesive tape" here, the kind a plumber would use on joints of pipe thermal insulation.

I'm (ex TV repair man) using copper adhesive tape and put on this a thin layer of 24k Gold (beaten gold).
Never had any problems again.

https://www.ebay.com/itm/360892458973

[Cerebus]

Yes mine arrived in only 6 days end to end. I think it's the seller as my JLCPCB order has entered the 4px void for the last 5 days now 

They seem to use Orange Connex as their courier or possibly for full logistics and in the past I'd sort of half noticed that stuff coming via Orange Connex seems to get here very quickly with no fuss.

Perhaps Orange Connex will put in a takeover bid for Royal Mail - please, pretty please. 

[Specmaster]

Hello people,

Sorry to interrupt, didn't want to, but Tautech just told me I may have a problem with TE and suggested I come here to say hi. So, hi...

Better grab a cup of coffee and packet of biscuits, just saying...

I know it is been said lots of times already, but thats what comes of being busy doing other stuff all day long. I'm late to the party, but yes, you will fit right in here, welcome to the clubhouse, we are all a really friendly bunch most of the time and as in all walks of life, you will see the occasional flare of mild hostilities between one or two members but just as suddenly it flares up, it also stops as it dawns on them that we all hold our own opinions on certain topics and nothing will ever change that. It would be very boring if we all thought the same things all the time I'm sure of that   

You have a problem you that you're struggling with, mention it here, and you'll find lots of very useful advice and support being sent your way.

Welcome to the TEA group.

[mnementh]

...And to add insult to injury... just as there appeared to be some progress with the MacPro itself, the 30in Cinema Display just kakked, after working perfectly for 3 days on various other PCs.  No smoke, not even a whimper; just refused to turn on or show any signs of life this morning.

mnem
Fuck you, Murphy.

So... after looking at a disassembly video: https://youtu.be/-1Ziwj0ZLsM on the 30in Cinema display, now I understand why the center of the display was darker when it first came up, and I am now much less sanguine aboot my chances of resurrecting it... unless I'm really lucky and it's just the 24V/7A power brick. 

We'll see. I dismantled/resurrected a few iPud power packs back when they were unobtanium... I do believe the brick is a better starting point.

While I have successfully brought video back up; all my attempts at reinstalling the OS from the recovery partition have met with abject failure; short version from much online research appears to be that since my user account is not the one that is associated with the original install, I'm boned. I have an iso that is alleged to work; however I need 8.5GB disc to burn it to, as this machine is just a hair too old for the Bootable USB makers to work with and... Oh, you get the idea. Every thing I try is met with "No, I don'n wanna!" and I've given up for now.

MINT runs well on it tho... but I'm having trouble figuring out the Kung Fu to take ownership of the old data drives so I can copy files from them and...   

Anyways... maybe some nice boring analog tinkery will be less painful.

mnem