Philips B4X82A/01 (1959)

The B4X82A-01 is a typical household radio from the late fifties. The case is not too expensive, made from plywood and plastic. It has pushbuttons for the band switch. It is offering SW, MW and LW bands plus an FM band and a gramophone input.

All the valves are Philips noval valves:

ECC85	(FM)RF amplifier and frequency changer
ECH81	(AM) frequency changer or (FM) IF amplifier,
EF85	IF amplifier,
EABC80	AM detector, FM detector and AF pre-amplifier
EL84	output penthode,
EM84	tuning indicator,
EZ80	rectifier.

The EM84 tuning indicator is a shifting bar-type.

I got this radio in september 2005. It came from an attic clean-up, the previous owner said it wasn't working. It had a generous layer of dust inside, and excrements from insects on the outside. The case had some scratches but did not seem to have suffered too much abuse. The plastic front and pushbuttons were yellowed, but looked quite OK.

I opened the case and cleaned out the radio a bit. As I could not reach all of the corners, I took out the chassis and removed dust and cobwebs under the chassis. Then I hooked up my HV power supply to the power supply electrolytics and slowly turned up the voltage to let the electrolytics recover. The leakage current was modest, so after half an hour I decided to plug it into mains power and switch it on.

No sound. I fiddled a bit with the band switch buttons and got some noise on MW. After applying some sontact fluid and some more fiddling with the switches, I got better sound. Now even the FM stage was working. I dried the contacts and measured the voltages at the output valve. The readings were ok. The coupling capacitor wasn't leaking. Then I replaced the scale illumination lamp, that was dark.

After some listening, I noticed the sound on FM was distorted. Not too badly, but nevertheless very noticeable. I replaced the electrolytic in the ratio detector circuit, but the distortion remained. I suspected the FM IF transformers and the detector transformer have to be realigned. But the distortion might also be caused by the greater modulation strength of today's FM radio stations.

Anyway, after a year I have traded this radio to make room for others.