Pilot model 75

[Sideband]

This radio was found at a local car boot sale. My sister-in-law spotted it on one of the stands whilst walking around. She knows absolutely nothing about radio’s but has an ability to spot interesting items and collectables, not just for herself but other people as well. She rang me to ask if I was ‘interested in an old wooden radio’ and mentioned tantalising things like ‘glass station indicator’ and ‘bakelite knobs’ and ‘Pilot’ on the back plate. As it was only £7.50 I asked her to buy it and then bring it round where I would re-imburse her.

She arrived and presented me with a Pilot model 75…a bit battle-scarred but otherwise seemingly complete. When I got it on the bench and removed the back it was quite clean inside with a full complement of Loctal valves….I hadn’t got a radio with these in so it would be interesting to see how they perform.

First I removed the chassis which enabled me to look underneath. This showed the usual proliferation of Hunts capacitors….the moulded type rather than the waxy ones but they would still be leaky….most of them had cracks around the casing allowing moisture in over the years. At this particular moment, I was very short of 0.1uF capacitors and being somewhat eager to try out my new toy, I changed the audio coupling capacitor, the tone corrector across the primary of the output transformer and just one of the original 0.1uF capacitors….the HT decoupler which was measuring about 100K. I had already checked for HT shorts and also the windings on the mains transformer and everything looked to be OK so I connected it to my variac, applied 185 volts and switched on, monitoring the HT at the same time. Slowly the HT started to rise and advancing the mains to 200V I heard an off-tune station. Slowly increasing the mains up to full over a period of 5 minutes had the set working really well with plenty of stations available. Probably this slow advance of mains was unnecessary but as I had not replaced all the capacitors at this stage, I was trying to avoid any unpleasant surprises. Besides I had no idea when the set was last used and although the smoothing caps measured OK, well there is nothing like being carefull and reviving them gently.

During tests, several minor faults were apparent. The volume, tone control and wavechange switch were dirty, cured by a shot of switch cleaner and the tuning gang was loose on it’s mountings. This was caused by the rubber mounts going hard and crumbling. Repair of these meant removing the tuning gang. I found a good substitute could be made from the rubber washers used in washing machine hoses. It is important that the tuning gang is able to ‘flex’ on it’s mountings or there is a danger that you can get microphony on some stations if the volume is turned up high. This is caused by mechanical feedback from the speaker, vibrating the vanes of the tuning capacitor.

Once the rubber mounts were repaired and the gang refitted, I removed each valve and cleaned the pins with a wire brush. One problem with Loctal valves is that the pins are rather short for the amount of valve and they seem to corrode and make poor contact in the holder. This is particularly the case with output valves and rectifiers that run hot. Cleaning with a wire brush and then a drop of switch cleaner on the pins will cure poor contacts but you may have to repeat it at some time in the future.

Next came the cabinet. This needed a lot more work than the radio. I stripped it down to bare wood and applied several coats of Danish oil. There is a painted strip along the bottom of the cabinet which I masked off and sprayed to give a better finish. The front ‘expanded metal’ speaker grille responded well to a good clean with meths and did not require respraying. While the cabinet was being worked on over several days, a new supply of 0.1uF capacitors had arrived so I was able to complete the restoration of the chassis.

When the set was reassembled, everything worked well. Several days of long tests have not revealed any other faults. It’s a slight departure from the usual shape with a curved back so the bottom of the radio is deeper than the top. All in all, quite a good looking set from 1954.

I've included some before and after pictures. Sorry about the rather grainy quality and the 'fish-eye' distortion in some of them. They were taken on a camera phone and not my usual digi camera which was being borrowed at the time.


Rich.

[MALC SCOTT]

Hi Rich, looks like a job well done to me A nice looking set, a model i have never seen before. I dont think i have a Pilot set in my collection, about time i did. Cheers, Malc.

[mark pirate]

I have one of these in my tuit pile, looking at how well yours has turned out
has put it nearer to the top of my list

Mark

[Nickthedentist]

That's a nice set, Richard, well done with the sympathetic restoration.

This model was the first ever valve radio I bought, at the age of 10 from my primary school jumble sale in the early 1980s for 50p. I still have it somewhere. And suprisingly, I didn't ruin it when I "restored" it first time round.

Mine has a different speaker, with a brown-painted basket. The smoothing cap was dated 1953. I remember that a neon screwdriver used to light if touched against the metal grille, so I was always wary of touching it when in use.

Nick.

[Steve_P]

Nicely done! I've not got one of these - maybe I should!

Cheers,

Steve P.

[Sideband]

There are a few of these about and I've seen a couple on eBay during the last year. The Loctal valves seem cheap and plentiful if you should need to replace any.


Rich.