[TonyDuell]

For those who are following this saga...

I've tried to clean up the goo and the potentiometers. The amplifier is a separate sub-chassis consisting of the front panel with all the controls, a motherboard at the top with lots of plug-in boards going downwards. The slide swithes are (mostly) on this motherboard, with operating levers on the top side.

So I took the whole lot out, took out all the plug-in boards (I did keep them in left and right channel sets), then dismantled the switch levers (which were covered in Evil Goo from the capstan belt), uscrewed the clock/timer, motherboard, scratch/rumble filter and front connector assembly from the panel. I could then move the motherboard away, and see the potentiometers.

By loosening the nut (10mm spanner) on each pot I could slide it out and remove the skew gear from the spindle. With them all removed the front panel was free. So it all got cleaned up.

I gave most of the pots a good squirt of propan-2-ol and worked them from end to end a few times. The recording level control that had given me problems I took apart (just remove the collar that couple to the skew gear, bend up the tabs and remove the bush/bearing, the front resistive track and lift out the wiper). It didn't look very worn, so I cleaned it well and bent up the wipers to make better contact.

Let's hope that does it. They may be rotary pots, but that doesn't mean they will be easy to get. For one thing they are smaller than normall (spindle looks to be about 4mm). And for another, Philips have designed it so that when the slider is at the bottom (minimum volume or level) the pot is fully clockwise. So they are all reverse log law (!). Why I do not know. They could have made the skew gear and the pins on the slider the mirror image of what they are and used normal log law potentiometers. Oh well...

It is mostly back together (and it wasn't hard). I want to clean up the timer while it is out, so I can't test things yet.