Quote:
Originally Posted by anden
Some further info - it's recommended to replace the selenium rectifier on these Zenith's with a diode.
The Y832 was Zenith's top of the line tabletop and the first radio to use their new electrostatic tweeters (2). The 8 inch main speaker was the largest to be used in a radio this size, according to Zenith.
The official name of the Y832 was the 'Super-Symphonaire'
When these are serviced, they sound fantastic !
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GREAT TRIVIA. I HAVE TWO! The first one I bought sounded OK but the tuning-dial and tuning-cap CORD was shot. It was clean and a little disappointed in the sensitivity (reception) and some static across all bands (all old caps). It is about to get cap transplant surgery of about 15 caps and may be a few resistor, plus the diode rectifier bypass.
The second one I bought sounds better, amazing, impressive, perfect, static free and has noticeably better sensitivity than the first. It also has a shot a tuning-dial cords.
I feel like the recap on the first will bring it up to specs. Amazing the tweeters work on both, which I am thrilled with.
They both need to have the tuning/dial re-strung. The strings are gone or barely there. I did some very subtle lube of the shaft, pulley and air-cap. What a difference.
They both will get be recapped. I am about to place an order for a slug of filters and electrolytic caps. Although my first overhaul of old tube radios, I feel confident after study of the schematics (for a few hours looking the the bottom of the chassis).
One had the selenium diode bypassed. I think they one they used was a 1N4004 which is good enough, but the solder is kind of crude and want to put some insulation on the leads to class it up. I'll go to 1N4007. I might up the 22ohm 1W diode down stream but don't think it needs it.
Since the DC does not drive the filament heaters on the Y832 I don't think the voltage is as critical. When going from selenium to silicon the voltage drop is less, so a drop down resistor is added. The plate voltage is 100-250 volts. I don't think a few more volts will kill the tubes, since line voltage is 117VAC. (WHAT DO YOU THINK?)
Thanks for the INFO! Cool stuff.