Test Equipment Anonymous (TEA) group therapy thread

[bd139]

Cool stuff. Pretty high demand for them. Order a load and sell 'em on ebay

BTW 7L12 diagnostics: -15V rail is short. +5V lights rail is short. Fix that, should at least be safe to plug it in.

[Specmaster]

That thought had crossed my mind, giving it a thought. Hopefully it will just shorted tants and then the moment of truth will it or wont it?

[bd139]

Well this one is definitely being difficult

Have managed to isolate it to the IF board. Fortunately the -15V comes into a distribution and filtering board and then off via jumpers to other boards. Moment you put the IF board back in it drops. There was a short on the 2nd LO board as well so haver replaced them. Getting there! There is still hope left.

I will say that this is the most complicated bit of electronics I have ever seen. Much 

[Specmaster]

Slowly slowly catchy monkey, you'll win I know it, especially if you show those remaining tants what's in store if the misbehave by way making examples out of the others with a club hammer 

In other news:-
Knobs have arrived look OK, have a slight texture to them, had a go over with a piece if fine wet and dry. Also they are loose on the shafts but is easily fixed with a small square of sellotape pushed onto the end of the shaft before pressing the knob on.

Colour is never going to a perfect match but I think this colour is as near as my print depot could get and it's called light stone. No doubt once its been used a few times it will begin to get a bit darker with finger grease etc.

Just noticed that there is a slight colour variation on the other knobs anyway.

EDIT:
For anyone interested in getting some 3D printing done here is the address of the printer direct as promised Print3d@techie.com and this is more suitable to people in the South East of the UK but postage would not be a problem but I could imagine that long distance printing / communication / checking samples could get a bit fraught with distance but its your choice if you don't either have a 3d printer or know anyone willing to do some for you.

[xrunner]

Get a small file and file the four slots on the side of the knob around the corner like the others it'll look even better.

[Specmaster]

I did think about this but as the walls are not particularly thick decided to leave well alone for fear of making it weaker or worse still making holes in it.

[med6753]

Working on the RCA scope. Things are not going too well.

Here's the power supply board re-capped and installed.



Results? Not so great. No horizontal sweep, which I had before. But the trace is no longer thick and out of focus so some progress there. Did some quick voltage measurements and from what I can tell all is OK. Checked the horizontal output transistors and they are sitting at +126VDC which seems right. Apparently I have to go back and check my interconnects again from the supply board. I'm overlooking something. But not this morning...gotta get some shut eye.

[mnementh]

Some quick porns. Will reply to other threads later. Major busy today 

Excellent packaging. Literally the best I've ever seen. Double wall box. Totally rigid packed and wrapped with cut outs for fragile controls 
(SNIP)

(SNIP)
Too busy to stuff it in the mainframe at the moment. Unfortunately however it appears to be full of tantalum shaped wankers so I'll probably have to dig around in there before I fire it up and check for shorts. Some of them result in toasty resistors which is bad for the general health of the unit.

Edit: couldn't resist. Took covers off sides. There isn't a square cm in that which hasn't got something crammed in it. 

Lead on, MacDuff!

*Sipping coffee*

I SO want to work for a company called "NapTech." I think I'm going to go practice "R&D" for them right now...   

Ok taken some time out to look at it. Literally the first tant I hit on the second mixer was short. This is going to be a long one.

https://youtu.be/3qYbVQu7YAQ

Slowly slowly catchy monkey, you'll win I know it, especially if you show those remaining tants what's in store if the misbehave by way making examples out of the others with a club hammer 

   In other news:-

Knobs have arrived look OK, have a slight texture to them, had a go over with a piece if fine wet and dry. Also they are loose on the shafts but is easily fixed with a small square of sellotape pushed onto the end of the shaft before pressing the knob on.

Colour is never going to a perfect match but I think this colour is as near as my print depot could get and it's called light stone. No doubt once its been used a few times it will begin to get a bit darker with finger grease etc.

Just noticed that there is a slight colour variation on the other knobs anyway.

Careful with the sanding... typical is 0.5-0.8mm outer wall thickness.

Now you see why I wanted to know which knob hole was closest to what you need.  (Jeezus; that sentence just sounds FILTHY) 

mnem
*Makes mental note to develop "Decades of Fade and Grime Boatanchor Knob" colored filament and make killing on Shapeways*   

[Specmaster]

Oh, I see, I thought you wanted which knob was the closest to the original because you did the 2 sizes that this scope has. It turns out that almost if not all the TDS range uses the same knobs albeit I think the later models had 6 flutes instead of the 4 on the smaller of the knobs.

I only did a very light sanding because of the wall thickness was not going to be that great so careful examination of the knob will reveal that it is a printed one even now after sanding but it has removed the worst after effects so it feels the same when you touch it. 

[mnementh]

As long as touching doesn't devolve into fondling, I think you'll be okay. 

You DID say you were going to have to let this one go...


mnem
"One can get too familiar with vegetables, you know!" ~ Chef Skinner

[Specmaster]

Arh yes, Ratatouille, a great cartoon film that one. I quite enjoy films of that nature, my family I'm daft as they are kids films but I can see beyond that and appreciate the craft that has gone into the making of them.

[mnementh]

In all honesty, with the vast wasteland that "Mainstream TV & Movies" has become; willfully pandering to and driving lower and lower the lowest common denominator, the last refuge for the truly creative has become children's programming.

The popularity of specialty segments like Adult Swim and Curiosity Stream are proof that adults still enjoy content that makes them think, FOX network and the peurilization of Public Broadcasting be damned.

 They've learned that they CAN make content that actually appeals to both kids and adults, and more importantly, that content SELLS.

mnem
*Desperately seeking a hard-to-find part for his AC that SHOULD NOT be so hard to find*

[Cerebus]

Ok taken some time out to look at it. Literally the first tant I hit on the second mixer was short. This is going to be a long one.

Especially with all that rigid/semi-rigid coax to crawl around. Good luck, something tells me you're going to need it.

[bd139]

Ok taken some time out to look at it. Literally the first tant I hit on the second mixer was short. This is going to be a long one.

Especially with all that rigid/semi-rigid coax to crawl around. Good luck, something tells me you're going to need it.

Fortunately the rigid coax end is ok. I traced the short to the board I have excavated but I can't find the damn thing. There was a wet tant that was short. Fixed that. I've pulled every socketed semiconductor out and tested for shorts. All the remaining tants are fine. this is NOT fun 

3 hours in ...



To confirm, if I yank out the supply cable loom for that board it comes up and sweeps and shows noise. Yig isn't running, neither is the IF strip though.

Edit: also I found tin whiskers in one of the RF cans. These should clear with a few tens of mA though so it isn't that.

[Specmaster]

There sure is a lot going on. on that small bench, mind the 867 doesn't get knocked off the end 

[mnementh]

Mmmmmm.... Tektronix spaghetti in Metcal sauce, with a parts bin garnish and a side of buttered PCB. Yum.

mnem
Maybe I need to go make some lunch...

[Specmaster]

That's just what I was thinking  so I'm off to eat.

[bd139]

Me too!

[bd139]

Found the wanker! Was pretending to be a silver mica inside the phase lock search oscillator.

[Specmaster]

Now teach him a lesson!

I think we need a hammer emoji

[Cerebus]

I must have been low on caffeine earlier to have missed this one:

I didn't get my knobs this morning as planned, ...

Oo, er, missus./That's what she said./More tea Vicar?

[Specmaster]

I must have been low on caffeine earlier to have missed this one:

I didn't get my knobs this morning as planned, ...

Oo, er, missus./That's what she said./More tea Vicar?

I hope she didn't say that cos she's in Madeira with her sis on hols.

[bd139]

Ooh Madeira. Fancy some cake now.

[Specmaster]

Got some Jaffa Cakes only 

[PA0PBZ]

I will say that this is the most complicated bit of electronics I have ever seen.

I was puzzled by this:



So open clearly doesn't mean there is nothing connected, but then what does it mean?