Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

That's right, boyzz and ghoulzz... just when you thought they'd FINALLY driven a stake through its crusty dust-filled heart, the undead creature that is Radio Shack returns yet AGAIN with a Clearance Sale eMail!

   

Free shipping for orders $19 & up!

Highlights: All sorts of adapters for cheap; including BNC, SMA and PL-259 couplers, some cheap 4K HDMI cables, and decent high-capacity NiMH batteries (if they're still made by SAFT) semi-cheap, including a CR-V3 Rechargeable for $4 for you die-hard photography buffs. Hopefully they won't be so old they can't hold a charge.

You can scavenge off the corpse of Tandy here. They have no shame; why should you?


mnem
"Sometimes you have to look at life like a dog does; if you can't eat or hump it, piss on it and walk away."

There are people who do think like dogs and do all of those things [emoji41]

From mobile device so predictive text might have struck again [emoji83]

[tggzzz]

I want one. Would work wonders in the supermarket car park.

I didn't have a camera on me, but yesterday my local mini-supermarket had a tractor parked outside. The wheels were, IIRC, around 6ft in diameter and 2ft wide.

[bd139]

I want one. Would work wonders in the supermarket car park.

I didn't have a camera on me, but yesterday my local mini-supermarket had a tractor parked outside. The wheels were, IIRC, around 6ft in diameter and 2ft wide.

Ideal squishing humans sized

I have a car full of D83s at the moment - woot

[Specmaster]

I want one. Would work wonders in the supermarket car park.

I didn't have a camera on me, but yesterday my local mini-supermarket had a tractor parked outside. The wheels were, IIRC, around 6ft in diameter and 2ft wide.

Ideal squishing humans sized

I have a car full of D83s at the moment - woot

Safe trip to my neck of the woods then, looking forward to seeing them working.

From mobile device so predictive text might have struck again [emoji83]

[tggzzz]

I want one. Would work wonders in the supermarket car park.

I didn't have a camera on me, but yesterday my local mini-supermarket had a tractor parked outside. The wheels were, IIRC, around 6ft in diameter and 2ft wide.

Ideal squishing humans sized

Bigger than that: squishing cars sprang to my mind. Remember Kenny Everett parking his tank?

[Specmaster]

I want one. Would work wonders in the supermarket car park.

I didn't have a camera on me, but yesterday my local mini-supermarket had a tractor parked outside. The wheels were, IIRC, around 6ft in diameter and 2ft wide.

Ideal squishing humans sized

Bigger than that: squishing cars sprang to my mind. Remember Kenny Everett parking his tank?

All done in the best possible taste🤣

From mobile device so predictive text might have struck again [emoji83]

[mnementh]

mnem
'nuff sed.

[tautech]

I have a car full of D83s at the moment - woot

And just what is this calibration fixture you speak of ? 

The multiplier is no big deal as there's a good thread here I'll dig out for you if you want to roll your own.
IIRC it was for a 465 which might only be 4 stages but another can be stitched on easily for a D83.
Is the 2nd unit is otherwise complete ?

[tautech]

mnem
'nuff sed.

Nice, low bridges, power lines and parking buildings will be a hazard. 

[xmo]

Test Equipment Anonymous group therapy?  This whole thread is a sham!

It's like you walk up to a door that has an "AA" sign on it but when you open it and go inside the first guy you see is Sam Malone.

And everybody knows your name.

Thankfully, I don't have a problem and I don't need any help.

[iainwhite]

Just out of curiosity... what breed of feathered friend is it? Garden variety robin or something else?

Looks like a European robin to me.

[bd139]

I have a car full of D83s at the moment - woot

And just what is this calibration fixture you speak of ? 

The multiplier is no big deal as there's a good thread here I'll dig out for you if you want to roll your own.
IIRC it was for a 465 which might only be 4 stages but another can be stitched on easily for a D83.
Is the 2nd unit is otherwise complete ?

Well got everything home. The main D83 seems to work although the HT starts whining after a couple of minutes and the filter caps are running stupid hot. Also some issues with channel 1 attenuator.  Second one I haven’t even cracked open yet. Lots of fixing fun to do.

Calibration fixture is a “raw” input plugin for the horizontal amp. Basically it just has a BNC and buffer that allows you to deliver a signal to the X amp directly.

Second unit is in bits. Seems complete however. Someone has attempted to repair the Y amp with wire wound ballast resistors  but otherwise looks good. The multiplier is shot on it.

I’ve seen the 465 multiplier rebuild. Might have a bash at that. Will get some microwave oven diodes off aliexpress

Hours of fun ahead. Will post some photos later if I get a few minutes.

Honestly I’m going to have to rebuild one of these from scratch by the looks and QA each board properly. Might take a while. It’s the learning that’s interesting though

[bd139]

Quick picture. Note the replaced labels (the other plugin fascia is better so I will swap it) and the replacement timebase knob someone made (I have someone who will send me a real one).

Original capacitors. Nice sharp trace.

[tautech]

I have a car full of D83s at the moment - woot

And just what is this calibration fixture you speak of ? 

The multiplier is no big deal as there's a good thread here I'll dig out for you if you want to roll your own.
IIRC it was for a 465 which might only be 4 stages but another can be stitched on easily for a D83.
Is the 2nd unit is otherwise complete ?

Well got everything home. The main D83 seems to work although the HT starts whining after a couple of minutes and the filter caps are running stupid hot. Also some issues with channel 1 attenuator.  Second one I haven’t even cracked open yet. Lots of fixing fun to do.

Yeah they're pretty easy to work on thankfully.

Calibration fixture is a “raw” input plugin for the horizontal amp. Basically it just has a BNC and buffer that allows you to deliver a signal to the X amp directly.

Never seen or hear of one.....but it's been a while since I had or studied a D83 manual.

I’ve seen the 465 multiplier rebuild. Might have a bash at that. Will get some microwave oven diodes off aliexpress

IIRC you'd just use the same spec as those in the DC restorer and I think I got some from RS....I did and just looked.....629-8691 = GP02-40 = 4KV 250mA

Hours of fun ahead. Will post some photos later if I get a few minutes.
Honestly I’m going to have to rebuild one of these from scratch by the looks and QA each board properly. Might take a while. It’s the learning that’s interesting though

Looking forward to them but maybe it's worthy of their own thread.......for mums sake. 

[tautech]

Quick picture. Note the replaced labels (the other plugin fascia is better so I will swap it) and the replacement timebase knob someone made (I have someone who will send me a real one).

Original capacitors. Nice sharp trace.

That pic looks photo-schopped and the trace green  , is it missing the blue CRT filter ?

Looks like she's served someone well as the labeling is worn completely away.   

[mnementh]

Test Equipment Anonymous group therapy?  This whole thread is a sham!

It's like you walk up to a door that has an "AA" sign on it but when you open it and go inside the first guy you see is Sam Malone.

And everybody knows your name.

Thankfully, I don't have a problem and I don't need any help.

You say that as if it were news.


mnem
Colas to Newcastle, etc. 

PPS: That was actually a typo... but I liked it better.

[mnementh]

Quick picture. Note the replaced labels (the other plugin fascia is better so I will swap it) and the replacement timebase knob someone made (I have someone who will send me a real one).

Original capacitors. Nice sharp trace.

That pic looks photo-schopped and the trace green  , is it missing the blue CRT filter ?

Looks like she's served someone well as the labeling is worn completely away.   

I was thinking that timebase selector was actually quite an inspired bit of fabricobble-ery. Gives the ol' girl some right outstanding character. 


mnem
*ploop*

[bd139]

Ok HT on the working one is not happy at all. I’m going to rebuild the power supply and HT section from scratch before anything blows up.

The second unit is complete but in pieces. Has some really naff repairs done to it.

Filter isn’t missing just very faded. I’ve swapped it for the other one and it looks better now

Edit: Fixed the HT. spidey was doing the electric boogaloo behind the HT board.

[bd139]

Triggers and displays trace up to 85MHz without any hiccups. Bandwidth (3dB point) looks to be around 62Mhz which is above the 50Mhz quoted. 

[tautech]

The multiplier is shot on it.

I’ve seen the 465 multiplier rebuild. Might have a bash at that. Will get some microwave oven diodes off aliexpress

So you don't have to go off hunting for it:
https://www.eevblog.com/forum/repair/tektronix-465/msg672083/#msg672083

Grapsus used 12KV diodes but it's all in that thread ^

[bd139]

Thanks for the link. It's whining again but not arcing now so this is a given that I'm going to rip it all out. I needed a project

Apparently the HT transformers on these are usually good so that's a relief. Plan is to get the HT board for the other unit and rebuild it using modern parts then substitute that one in and a new multiplier. Also rebuild the shot one's power supply and stuff that in the good one. Least risk all around then.

Easy to get to all the boards in these unlike some tek equipment!

[tautech]

Thanks for the link. It's whining again but not arcing now so this is a given that I'm going to rip it all out. I needed a project

All the high value resistors in the EHT circuitry had drifted like hell in the D83 I had and the HV ceramics in the DC restorer were sick too. They more than anything else really cleaned up the traces and made them needle sharp. 
IIRC some of the HV axial caps were sus too but you probably know all that about these.

Apparently the HT transformers on these are usually good so that's a relief.

Sadly the copied manual I got from the UK had all the measurements handwritten in for the transformer, R's & L's but that copy went with it when I sold it. 
The copies online aren't from the same source but the crowd I got it from are still around as I stumbled upon them again just the other day. You'd only need the mainframe manual from them to get those measurements and IIRC it was still the same price I paid yonks ago ~10 quid.
I'll hunt them out if you like .......if I can bloody well remember their name. 

I think it was Telford:
http://www.telford-electronics.co.uk/index.php

You can probably ask them to check....the transformer measurements were written in/on the schematics for the EHT supply.

[bd139]

Yes this has the original caps in it. They are rotten old bits of crap. Flat ceramics, speckled and cracked and film ones which look cracked too. Will be replaced. I've priced a few up and they're not that expensive fortunately. Will order next week once I've checked it over properly. You can apparently get a suitable equivalent multiplier from a company called High Voltage Modules in Braintree here in the UK. I'll give them a call.

Thanks for the link. I've got a spare HT transformer now in the other scope so I might unwind and count it out.

Have just ordered power supply caps. Cost a whopping £5 from RS so far. Embarrassingly small compared to the originals!

[mnementh]

Thanks for the link. It's whining again but not arcing now so this is a given that I'm going to rip it all out. I needed a project

Apparently the HT transformers on these are usually good so that's a relief. Plan is to get the HT board for the other unit and rebuild it using modern parts then substitute that one in and a new multiplier. Also rebuild the shot one's power supply and stuff that in the good one. Least risk all around then.

Easy to get to all the boards in these unlike some tek equipment!

I did that same job on my Tek 2230 a decade ago; then replaced the HV multiplier flyback again this last time I worked on it. Altogether a right crunky affair; I get that the whole mess allowed them to run the beam at lower current, therefore better response and sharper focus at higher frequency... but damn. It's one of those designs that just seems to taunt Murphy.

And worse yet, they "inspired" the designers of your scope to follow in the same ill-advised foosteps...


mnem
Not a fan. Not a grommet, either.

[Specmaster]

Essex to the rescue again