Battling with an '80 radio/tape.

[boater sam]

Does anyone have a circuit or schematic for Ferguson 3T26 radio/tape player? I believe it is in Radio TV  Servicing 1984 which I don't have nor is it on my CD.
This one I am struggling with has uncontrollable high volume and its not the volume pot. I have only 849 ohms across the pot pcb terminals with it disconnected. Searching around I can find no simple reason and the pcb is not easy to follow through.

Most grateful for any assistance, thank you.

Sam.

[ppppenguin]

Apologies for scan quality. Any hints on scanning books which don't lie flat?

It's on p568 et seq of R&TVS 1984-5

[boater sam]

Thank you, So fast too!
I'll try to work off that. I have chanced C409 without any positive result so far. Its not obvious what could be shunting the pot.
 
Scanning books without destroying them is well nigh impossible I found.

Sam.

[ppppenguin]

There are specialist book scanners that should help: https://www.digitalcameraworld.com/buyin...ok-scanner but unless you're doing a lot of book scanning they are probably not worth it.

[Dave Moll]

Jeffrey's images are probably about the best that can be obtained with a flatbed scanner (without dismantling the book!).

Below is my attempt - with the lid up and pressing as hard as I felt comfortable on the spine.

[boater sam]

Thanks to Jeffrey and David the problem is solved, its all working normally.

I cleaned all the switches and both pots, replaced 3 capacitors around the volume and tone controls and it worked.
The capacitors were off spec, leaking a bit and I suspect were passing a bit of DC into the amp chip.
These radios with little but the odd chip in them are not my scene but I felt that this one was worth saving. It cost very little to buy or repair.
They do however perform amazingly well, the FM quality on this one is astounding even with the aerial fully collapsed.

Thanks again for the help guys,

Sam.

[boater sam]

Now its working and still in bits as so far as the plastic case is still apart and the handle and knobs are off I might as well clean it up and make it look a well as it can without spending too much time on it.

Its filthy, it was looking as if it was kicking around a dirty commercial kitchen for years, covered in grease and fat.

 I scraped off as much as possible before sticking it in a sink full of hot soapy water, not the electronic bits of course. I discovered the the knobs are fluted and grooved and that the case has lots of fine groove areas too.

It came up quite well considering. Most of the original silver finish is still intact, some staining on the base from leaking batteries in the past and the battery connector pad and springs were well corroded but vinegar sorted that out.
Reassembled it looks presentable.

I can't full test the tape player as now I don't have a cassette tape but it winds both ways and all the mechanism works.

Flushed with success I have decided to sort out another odd ball radio that I always said I would never touch, a Chinees TR82 copy, AM and FM, mains and battery. It came with the previous Ferguson and is in the same disgusting filthy condition but works OK. So that's for a future post.

Sam.

[boater sam]

Now its working and still in bits as so far as the plastic case is still apart and the handle and knobs are off I might as well clean it up and make it look a well as it can without spending too much time on it.

Its filthy, it was looking as if it was kicking around a dirty commercial kitchen for years, covered in grease and fat.

 I scraped off as much as possible before sticking it in a sink full of hot soapy water, not the electronic bits of course. I discovered the the knobs are fluted and grooved and that the case has lots of fine groove areas too.

It came up quite well considering. Most of the original silver finish is still intact, some staining on the base from leaking batteries in the past and the battery connector pad and springs were well corroded but vinegar sorted that out.
Reassembled it looks presentable.

I can't full test the tape player as now I don't have a cassette tape but it winds both ways and all the mechanism works.

Flushed with success I have decided to sort out another odd ball radio that I always said I would never touch, a Chinees Bush TR82 copy, AM and FM, mains and battery. It came with the previous Ferguson and is in the same disgusting filthy condition but works OK. So that's for a future post.

Sam.