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Old 09-19-2013, 11:40 AM
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TinCanAlley TinCanAlley is offline
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Join Date: Sep 2008
Location: So Cal, CA
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Quote:
Originally Posted by Zenith26kc20 View Post
Check the horizontal output transistor emitter to collector on ohms. If it is bad it will read near or at zero ohms. Diode checking does no good as some of these have damper diodes in the transistor itself. If it is bad, once replaced, before you turn it on, disconnect the tripler from the flyback (at the tripler). The lead is soldered on to the tripler but you will have to scrape away the silicone on the tripler post to get at the solder. Some (few) of the EC chassis had the lead come out of the tripleer and solder to the flyback. If so, it will have to be CAREFULLY unsoldered from the flyback. A picture of the flyback/tripler would be very helpful. These sets were known to have triplers fail. Also, follow the lead from the transistor to the horizontal driver transformer. There is a 1.5 ohm resistor with a small electrolytic across it. You will know it because the positive of the electrolytic is on ground. This pair fail and can also kill the horizontal output transistor. Also, from the collector of the horizontal output transistor, there are a number of capacitors (hopefully red/orange, or white, if original). Check these. If they are white change them. Zenith had a lot of problems with the white ones. Pictures of the horizontal area would be helpful as well as the horizontal area unter the chassis.
Okay, I did the ohm test and got 8.9 collector to base, 2.3 collector to emitter and 9.5 emitter to base.

I'll check the 1.5 resistor. The capacitor with it was replace over a month ago when I recapped the chassis. All electrolytic caps were replaced.

I replaced all the white safety caps a couple of months ago (5 of them).

I'll get myself some sensor safe RTV so I can remove the tripler input lead and insulate it again when I put it back.
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