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Tektronix 212 portable 2 trace scope needs fixin'

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powerdoc

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OK, where do I start? I've never had a solid state scope that malfunctioned. I bought this yesterday from a guy on CL; we met in a restaurant lot (kinda' like a drug deal) and I gave him a few bucks and off we went. He assured me he got a 60hz trace and when he wakes up in hell tomorrow morning........

Anyway, I have downloaded the appropriate manual. There is only one trace I can find and it looks like a wavy blob; it won't focus properly. The batteries haven't leaked, one good thing, and it appears to have service marks from 1984, not sure if that was just the original assembly markings.

So generally, where does one start besides not getting between ground the the trace voltage? Any references I can use? If the batteries are toast (they probably are) do they affect the operation if the AC is used for power?

Any help appreciated. Thanks guys!
 

KeepItSimpleStupid

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Most Helpful Member
The batteries MUST be good for this scope to work on AC. The batteries are probably toast. They can still be found without the caps and clips. The connectors are 3 pin, so it's nearly impossible to reverse them.
 
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powerdoc

New Member
In the manual I have, which is a military one, I can't find any schematic or description of the battery pack per se; there appears to be some diode or thermistor in the battery pack; anyone know the spec for this?
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
There wasn't anything else in the pack when I replaced mine. You can get packs at http://www.bulbtronics.com/Search-The-Warehouse/BTSearchOptions.aspx Search for Tektronix, Medical, Oscilloscope 212. You'll need 2 packs and some heat shrink tubing to finish the job. In the worst case, the wires will be too short or they will be severely oxidized and will have to be replaced. Dressing the wires is extremely important. I just wanted to warn you.

I actually need the two plastic pieces (working on an ersatz replacement - really don't want to mold two) on the battery pack and I haven't had time to deal with the calibration issue on the one I have.
 

powerdoc

New Member
I redid the battery packs and by gosh it came to life! 2 traces with a normal sweep - beautiful! The wires to the board from the battery pack are made of something that just doesn't like to be soldered. I got some computer fan extension cables which have the plug end and it works well. Now to put it all back together, the jigsaw puzzle that it is.
 

KeepItSimpleStupid

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Congrats! Bet your really happy!? Told you about the wires. I never saw wires that badly oxidized before either. I used to think the bare copper hook up wire RS sold was pretty hard to solder. Nice idea to use a fan connector too.

Remember that the bandwidth is only 500 kHz.

I used the one at work a lot until someone accelerated it at 9.8 m/s^2.
 

crutschow

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I used the one at work a lot until someone accelerated it at 9.8 m/s^2.
But it's not the acceleration of the fall that's the killer, it's the sudden stop at the end. ;)
 

Reloadron

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Years ago I had a few of those, anyway, I "think" they were model 212 in a junk box at work. I know I gave one away to a guy in the QC department and the other may still be in the junk box if it was never pitched. I do recall they both worked well. Anyway, if I have time Monday I'll see exactly what the remaining unit is and if it still exist. If you want it then it's yours. I am not sure it still exist but I don't want anything for it if it exist. It was scrapped out years ago, like 20 years ago likely. Till Monday I won't know anything.

Ron
 
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