britishvac: Repair radio

ID: 481834
britishvac: Repair radio 
22.Aug.18 22:48
987

Michael Watterson (IRL)
Editor
Articles: 1033
Count of Thanks: 3

Make sure it's unplugged from the mains supply. Remove kettle and teapot, then place upside down. Take out the four screws on the base plate.

Unplug the mains wires from the Radio on/off switch as they get in the way. Unplug the 6V - 0 - 6V AC supply and the audio out.

Removal of PCB.

Pull off the two knobs.

Unscrew the speaker retaining clip. It also hooks through a slot in the PCB.

Red  Arrow.

Now examine the photo with arrows 1 to 3

PCB mounting

1 is the screw mount.
Clip (2) needs to be pushed back. Then the PCB is tilted up at front slightly and forward of the rear mounts (3).

Do NOT remove ANY screws on the PCB!

Do the reverse to refit, except the two plastic clips on front of the speaker need pushed with screwdriver to get speaker back into place before tightening the metal clip. Note it needs to hook through slot 1 on PCB.

Don't forget the two plugs on the PCB and the two wires to the radio on/off switch (mains and transformer).

Faults on my model

No audio at all. The switch on the mono 3.5" jack socket was high resistance. I unscrewed it, released top connection for tip of jack by pressing screwdriver into slot near the front. Cleaned and reassembled.

Still no audible sound, but very low level visible on the 'scope. The input had plenty of level on FM tuned to a local station. The output 220uF was where it was lost. It was only 10uF and 120 Ohms ESR. There was audible sound with a replacement fitted. Likely other capacitors have dried out as the audio level seems low.

The VHF-FM aerial is a trailing wire which had been cut and badly extended outside the case. I added a new length.

The switches for the kettle and tea pot may need cleaning as the those need jiggled to start it. The kettle has a sealed lid and uses the steam pressure to push water up the pipe from base of kettle to tea pot spout.

 

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