I picked up this old Philips at a local sale.

The Philips 170A was the first model in their post war range. Originally sold in 1946 for £18 + Tax.

This radio had seen some attention in the past and needed some work done before power could be applied. The mains cable was connected in a dangerous fashion, with bare live connections at the back of the set.

This set had "wet" electrolytic capacitors in it's power supply. Instead of a paste electrolyte they had a liquid. One of the capacitors had already been changed and the other ran very hot when I tested it. I took out it's old innards and installed a new capacitor in the inside the old case. Also found that the cathode bypass capacitor C29 was completely stuffed and had to be replaced.

Click here for a diagram

Power was carefully applied with a variac and the HT came up OK. Though there was no sound :-(

Voltage readings all looked OK and poking about with a scope showed there was a problem with V3 (IF AMP) an EF39. Luckily it was only a problem with the metallic screen on the valve, which I was able to repair with conductive paint.

There were lots of crackles and pops from the controls, which were a lot better after an attack of switch cleaner. The dial didn't light up properly because the frosted plate behind it had been painted with white emulsion. After this was scraped off and the plate properly frosted it lit up OK.

A view from the back.

The quality of sound is excellent 

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 !)