Marconiphone Transistor portable / car radio

I remember my physics teacher having one of these sets in his car. I think it was nicked out of the car whilst parked near the Odeon Streatham High Road. Funny how you remember things. Quite a nice portable, LW, MW and VHF and this time the VHF band goes all the way to 108 Mhz! It was aimed at the car market and it’s slim design enabled it to sit on the parcel shelf. The speaker faced out to the front, but the back was open with a similar grill, so the sound could come out and go behind your dash board. It had a car aerial socket on the back, with a button on the front marked CAR. This disconnected the internal antenna when pushed. It also has a LIGHT button which when you hold it in, lights up the tuning dial. So if you were driving along and you wanted to change stations, you would have to hold the light button in, use your other hand to turn the tuning knob, steer the car with your knees and arrive at casualty. It has a preset button for 208 mtrs, Radio Luxembourg , cool. Work in progress. Managed to get the VHF working well, but LW, MW totally dead. Have a feeling we may have a dead AF115-6 transistor in the AM RF section. And, we all know how to fix that fault! These were Mullard germanium RF transistors and used in local oscillator and RF amplification circuits in radios. Metal cased with 4 leads, one being a shield for RF reasons. A common issue was that the junction inside the device used to break loose, probably due to physical shock and vibrations, especially is used in car radios. If it touched the shielded case, the circuit would not work. So, when confronted with a dead set from an RF point of view, the first thing to do is to snip or unsolder the shield legs of any AF115 types. 89.547% you are rewarded with a working set. I learned this in my primary school days in the ‘60s and have to admit, made good pocket money snipping shield legs off AF115s, fitted in school friends dad’s car radios. With some Duraglit from the shed, I would polish the output transistors that were visible on the rear of the sets and say that these had been changed. Got a few extra bob. Not that I would do that now you know.

Leave a Comment

Your email address will not be published.

Scroll to Top