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Old 06-11-2017, 10:49 PM
Findm-Keepm's Avatar
Findm-Keepm Findm-Keepm is offline
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Join Date: Jun 2007
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Quote:
Originally Posted by kf4rca View Post
If its like their waveform monitors used in TV broadcast with the switching power supply, I'd say you've got some bad caps on the secondary side of the switching supply transformer.
T912 has a pure linear power supply and is easy to service. 90% of the ones I've serviced in Cal Labs (the Navy used them in the mine countermeasures shop) had pure knobology issues. Nothing Electrically wrong, just knob position/rookie issues. "The XYZs of Scopes" is a good tutorial for analog scopes. Try to find a hardcopy (hint:non-PDF) from prior to 1991, when Tek changed it to include the DSO (digital) and Mixed signal scopes/microchannel architecture scopes. They shortened the text in the analog side, convinced that everyone would be using their DSOs only.

They are dual channel, so if your scope clock works in X-Y mode, you are okay. All of the scope clocks I've seen are X-Y types, like curve tracer kits and TV-on-a-scope kits use. The TV-on-a-scope kits also use the "Z" channel, available on all Tek analog scopes.

The T912 manual (available free on the web) has the full schematics, operation info, and troubleshooting matrices.

One question - has anyone messed with these before? A lot of these are now hangar-queens that others have cannibalized, but offer up for parts. I got one (ex-NASA) that had most of the transistors pulled from it. Good CRT and power supply, but I passed it on to a friend. He got it working by merely ordering and replacing the transistors. The Storage board was thought to be toast, but it turned out to be a flood gun power supply issue - the 7805 regulator couldn't handle the initial surge. One visit to the junkbox fixed that.

These are among the most repairable scopes out there with ZERO custom chips - all are the 156-prefixed ICs, commercially available. Knobs and pots are hard to find for some of the T-series, but with your horde of scopes, maybe you can make several good ones. Working ones rarely go for more than 60 bucks - it is a 10MHz scope, after all....
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CET- Consumer Repair and Avionics ('88)
"Capacitor Cosmetologist since '79"

When fuses go to work, they quit!

Last edited by Findm-Keepm; 06-11-2017 at 10:54 PM. Reason: added clarification on DSOs/dual channel oops
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