Magnavox Astrosonic R222 Chassis

[csimone]

Hi all,

I recently acquired a Magnavox Astrosonic 1P3661 (chassis R22276 DE) from its original owner. It’s in great condition and is solid state. I was able to restore the W821 turntable with a tear down, relube, new stylus, and new idler wheel.

I’m now focusing on the chassis. Overall sounds good after pots and switches were cleaned. The issue is one channel sounds slightly louder than the other. Given its age, I figure it’s time to take a close look at the electronics, none visibly appear damaged.

I’m posting to here to ask recommendations on how to approach this and what components to test and replace. I now have the chassis schematic.

I’ve read forums about replacing the electrolytic capacitors, but I’m wondering if I also need to be looking at the output transistors, resistors, other capacitors, and crossovers?

Both tuners, the phono and tape lines sound good, besides the difference in volume. I’ve read that if I replace capacitors in the FM tuner I will have to realign the tuner. Is replacing these capacitors worth it?

Attached are photos of the unit and the output transistors. Anyone know how to identify these type of transistors?

thanks!

 

[Lavane]

The output transistors may be Germanium. So he careful you don't short one out, they may he difficult to find new old stock to replace them. There may be a balance pot in the amplifier section? As old as it is, replacing all the electrolytic capacitors is probably a good idea. You can even use polypropylene film capacitors to replace any electrolytics caps in the crossovers. Is the amplifier on its own chassis, or is it one of those all in one tuner/preamp/amps thats basically a receiver? Ha ing one channel slightly louder could Also jus5 be the dual volume control pot not tracking evenly.

 

[larryderouin]

R222 series is a receiver. 1968-70 era. About 15Wpc.
Output's are Germanium. Regrease them as the old heatsink grease has effectively dried up.

You can replace the Electrolytics in the tuner section (2-3) without affecting alignment.

Replace the E-Lytics on the amp board and the P.S. eq board. Do all of them. More often than not with the R222 series I've done, that takes care of the balance problems.

Balance pot and Volume pot are together. Usually works pretty good. DeOxit and Faderlube helps a lot on the R222.