Zenith Model 825

[Urizen]

This radio was given to me by a customer today, and I know zilch about antique radios. It appears to have seven tubes, some that I have never seen before.

Question is, is it worth salvaging? The guy said it powered up, but I dare not do so until it is properly serviced. (no variac here)

The case looks like it could be made a thing of beauty in the proper hands. The guy who gave it to me says that he has the missing knob at home, and will bring it to me Monday.

Thanks!

Regards,

Ken

[Urizen]

Found this pic of a restored 825:

[Tom Bavis]

I think that is a 1934 model. Other "800" models are listed for $150-250 value in the Collector's Guide to Antique Radios. Tubes for this are no big deal - I probably have them all. Power transformer is at risk until the capacitors are replaced.

Schematic: http://www.nostalgiaair.org/PagesByM...8/M0025398.pdf

[Urizen]

Thanks for the schematic. This might be a good starter project. I need to bone up on my soldering skills.

[Jeffhs]

One thing I noticed after seeing the pictures of the chassis of that Zenith was that at least two tubes looked as if they were not fully seated in their sockets. This could result in intermittent operation (if the radio works at all), not to mention the possibility of B+ (plate voltage) arcing.

If you don't have a Variac, you can use a 100-watt light bulb in series with the radio's line cord. When the set is plugged in and turned on, the bulb should light normally if all is well. (Replace the line cord if the insulation is brittle, cracking, or if there are any bare spots.) If the bulb lights up with a bright flash and burns out as soon as the radio is plugged in and/or turned on, there is a dangerous short somewhere in the power supply, which must be corrected before the radio is used again. (There will be no further damage to the radio if the bulb flashes and burns out due to an overload or any other reason, as the bulb is in series with the line cord and will act as a fuse if there are any problems.) Look for shorted filter capacitors, a shorted rectifier tube, or even, worst case, a shorted power transformer. I'd check the filters first, as they are positioned in the power supply in such a way as to short the AC line directly to ground if they are defective; the same thing applies to the rectifier tube if it shorts. (Tom Bavis's comments regarding replacing the filter caps to protect the power transformer are sage advice; the transformer could be damaged or destroyed if the filters are bad). I don't know if that Zenith radio has a fuse in the power supply or not (many very old radios did not, relying on the house fuses if anything shorted), but if not, I'd put one in, just to be safe.

I'm not familiar with your Zenith radio (the oldest radio in my own collection is a 1951 H-511 All-American Five table model), but Zenith was a very, very good make of radios/hi-fi equipment, and later TV sets, until the late 1980s. You will have a very fine radio once you get your model 825 working. It's almost impossible to kill a Zenith, and when they are working well, they are excellent sets. All six of my Zenith radios are working extremely well at this point, considering their ages (the newest one is a 1980 vintage transistor portable). I've been a Zenith radio collector now for five years (starting with the H511 in 2002) and have liked Zenith radios, TVs and high-fidelity gear longer than that. At one point in my life (some 35 years ago[!]), half the basement of my former home was full of old TVs, one of which was a Zenith. I've had several other Zenith TVs and radios (and even one Zenith stereo phonograph) as well, so you can tell I liked this brand when they were synonymous with quality. I still like the older Zeniths, but I wouldn't put much trust in newer sets from the company. The sole exception is my Zenith R-70 AM/FM nine-transistor portable from 1980; it looks and sounds great, even after 27 years. Zenith was not kidding when they said "the quality goes in before the name goes on" in their earlier years. Too bad that all went down the drain in the late eighties with about the sickest-sounding glub I ever heard.