I picked up this old Philips radio at a market in Mitchelstown (where the cheese comes from), while on holiday in the summer of 2000.

It seemed like quite a nice set, with a good solid case and ivory style push buttons on the front. There is also a wooden version of the same radio. This set has seven valves and covers from long wave through to VHF FM. These radios were released for sale in November 1954 for £23.

Click here for a diagram

On initial inspection of the set it seemed complete and showed no signs of previous repair attempts. There were FIVE ! separate drive cords and some very complicated switching arrangements. Thankfully none of the cords needed attention and the switches all responded to contact cleaner.

As the radio hadn't been used in a long time, a lot of the controls were very stiff. Some light oil on the switch mechanisms made them operate like new, though the volume / tone control assembly had to be dismantled and cleaned.

I removed the valves and slowly brought up the HT with an external power supply (limited current to avoid damage to the capacitors). This all went according to plan, so I put the valves back in and powered it up slowly through a variac. Amazingly the radio worked and I was able to receive stations on all of it's bands (I'm usually not this lucky). However the volume control wasn't working properly and the sensitivity was a bit poor.

The volume control turned out to have a crack in it's carbon track. It was an old type of variable resistor, which had a tap that was used as part of the tone control (to boost bass when listening at low volume levels). I ended up replacing the pot with a modern equivalent and disconnecting the bass boost part of the circuit.

A friend of mine checked the valves for me and we found that two of them were down on spec (V1 ECC85 and V3 EBF80). With a couple of new valves the performance of the set was a lot better, but still wasn't quite as good as it should be.

You can click on the component numbers to see their pictures.

Voltage checks around the IF stage found some strange screen voltages.C32 and R21 were faulty and affecting the screen voltages of V3 and V4 (10 volts instead of 80 ish). Changing these restored the screen voltages and made a great difference to the sensitivity of the set. There were lots of stations being received (even with no antenna), but some other problems had appeared.

FM reception was now very distorted, so I checked around the FM detector (I figured the AF section of the radio must be OK as AM reception was very good) and found C49 was faulty. It was very low in capacitance and when I removed it from the set I could see a crack in its case. When this was replaced the quality of the FM reception was greatly improved. FM didn't sound so bad until the IF amplifier was repaired (the increase in the IF signal fed into the FM detector showed up the problem with the reservoir capacitor).

Also the AF coupling capacitor C54 was leaking some DC through to the control grid on the output valve (7 volts). This can cause the output valve to draw too much current through the output transformer. This capacitor is an example of the infamous Philips black capacitor. After this was changed the grid voltage was correct, but there was no noticeable difference in audio quality. 

The quality of sound is excellent and it certainly makes a nice change to be able to listen to VHF (which is not available on any of my other old radios). Luckily it didn't need any expensive parts (just a lot of time).

CLICK HERE TO HEAR RADIO RUNNING

Don't forget that there are lethal high voltages in old valve equipment, don't even take the back off an old radio if you don't know how to deal with these. Do as much work as possible with the power OFF. If you have to make adjustments or take readings with power applied, be VERY careful. Use insulated tools and only use one hand (so if you do touch something you may avoid putting yourself in the unfortunate position where electrical current flows from one hand to another, though your heart). Beware capacitors that hold high voltage charges even when equipment is disconnected from the mains.

On a more positive note, valve radios aren't hard to fix and they make nice useable "furniture" for your home. They will still work after a nuclear bomb goes off near your house (solid state equipment is damaged by the huge electromagnetic pulse). Someday they might be worth a lot of money, so the more old radios you have the richer you'll be (I'll be a millionaire !)