1974 Zenith Avanti (25EC58)

[Adam]

I did some work on the b/w set. The set worked fine except for the remote receiver unit, so on the tv chassis I just recapped the bumblebees, and kept the original electrolytic cans for now.

On the remote chassis, the selenium rectifier was open, and that 2 section 40mfd electrolytic was bad. I put a diode in, replaced all the electrolytics and the remote worked ... for just a few minutes ... Then the channel changer still worked, but the vol control didn't. First I swapped the 2 transistors that operated the channel changer and the volume control (X5 and X6), but the channel control still worked and the vol still didn't. Then I went and adjusted the alignment, which I was able to improve a little, but even though the unit appeared to be working and the alignment was good, it still wouldn't operate the volume switch.

The problem turned out to be mechanical, there is a crack in that plastic gear in which the spring which turns it forward gets stuck, and then doesn't allow the disc to turn (see 2nd pic). These plastic gears seem to be the one weak point in these Zeniths. The repairs I did to the plastic gears on the tuner motor on my Zenith color set with the SC400 are still holding, so I think this one should be ok too.

The only other problems with the set are the rubber belt for the fine tuning was broken, which I already replaced, and the channel indicator light is burned out.

[drh4683]

Looks nice. Glad you were able to get those going. Both those sets just sat in my storage unit and never got around to even taking the back off them. Nice to see them coming back to life and glad to see you used Sprague Atoms for the lytics! (made in USA and the best!). Watch out for that space command chassis though. That large heat shield for the transistors is asbestos.