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Philips A5X83A tuner (1958)

A5X83A-front.jpg
The A5X83A was the first Philips radio without AF amplifier or speakers. In the late 1950-ies this would have been an awkward concept for most people. But if you had the money to spend on a “HiFi” sound system this would have been a sensible choice. This model has AM and FM bands, with FM coverage from 87 to 108 MHz. It is really a very sensitive receiver as I found out.

The A5X83A is a tuner, not a complete radio. The model is from 1958, and it is modernistic in its design. My specimen looks like it is from 1960, it might be an A5X83A-19 but somebody has blotted out the “-00” or “-19” part on the type label at the back, so I don't know. This tuner has more valves than some radios that do have an AF output stage:

So it has one IF stage more than most other receivers. Another point of luxury is the use of the triode in the EABC80 to suppress AF output if no signal is received on FM. This “squelch” or “silent tuning” function makes the tuner easier to use at the cost of an extra valve.

When I opened the case, I saw the previous owner had already started cleaning the tuner. On the inside, a layer of greasy dust was covering the chassis. I pulled the valves and cleaned the inside.

A view of the chassis after cleaning, valves not yet in place.

A view of the chassis after cleaning, valves not yet in place.

I tried the tuner and was pleasantly surprised by its sensitivity. On AM as well as on FM it received a lot of stations and produced a good sound quality (by the way, the actual sound was coming from a set of computer speakers, which is of course a bit of an insult, but I didn't have a valve amplifier at hand).

The position of the pointer was wrong on both AM and FM. For AM this was simply a question of shifting the pointer a bit on the tuning string. But on FM, I needed to set one of the trimmers on the FM tuning module. I did this using stations with known frequency as a reference. Later on, with my newly built FM signal generator I would be able to confirm the scale was tuned quite well.

The chassis reassembled and operative.

The chassis reassembled and operative.

Before I was satisfied, I needed to make a few repairs to the case. The case construction is very simple: no elaborate shrinery, just a U-shaped plywood cover with fine veneer. One corner was broken, but the piece of plywood came with it. I glued it in place using white glue and filled the cracks. Then I filled some deep dents in the case, sanded it slightly and sprayed it with a coat of clear polyurethane varnish. This gives very good results on some places, but I don't seem to be able to get a nice even coat. The result is reasonable though, but with some rough patches and drips.

After this, I reassembled the tuner. I'll need to find a more worthy amplifier to use it.

Copyright © 2009 by Onno's E-page         published 2009-11-28