Tricity Sovereign Oven controller fix

[admin]

I see much discussion here about this cooker. I had one from 1988 to 2003 and had cause to repair a couple of faults amongst which was the oven control problem which seems to afflict most examples sooner or later (ie you press the buttons and turn the timer knob and nothing happens). As an electronics engineer by training I was curious as to why this should be and it didn’t take long to work out what caused it.

The actual switches inside the control unit are little more than the sort of thing you would find in a calculator ie a conductive rubber pad which is pressed onto a pair of contacts formed from the segmented track on the circuit board. Bridging the contacts with the pad completes the circuit. The problem is that the contacts get contaminated and the rubber pad loses it’s conductivity as it’s graphite coating breaks down or wears off.

The fix is simple enough for someone with basic skills. I won’t go into great detail on how to dismantle it as it was a few years ago and i can’t remember the fine detail but if you can’t get it apart then best leave alone. However, if you do manage it, simply ease off the metal cap from each individual push button mounted on the PCB and remove the small rubber pad. Use an electrical contact cleaner on the PCB contacts and a de-greaser on the pad. Powder a little of the lead of a pencil or better still the brush from an old, small electric motor, dip the face of the pad into a little drop of Evostick, wipe the excess glue off and dip straight into the powdered graphite. Leave about 2 hours, reassemble switches, controller and cooker and Presto, you’ll barely have to touch the buttons to set the clock or oven timer.

This fix lasted at least 5 years before it needed re-doing and was better than spending £280 which is what I was quoted for the controller in 1995, when you could still get them !

If this helps anyone i’d be pleased to know.

Good luck.

[admin]

Re: Tricity Sovereign Oven controller fix

I had similar problems, what I did was to remove the defective switches, and connect about 12 inches of ribbon cable to the PCB. I fitted some minature pushbutton switches directly onto the glass facia, using the holes where the original switch operating buttons were fitted, the new switches were connected to the ribbon cable, which in turn was connected to the PCB (as already stated).
I did need to cut away a section of the red cover, to allow the cable to exit the timer assembly. The switches used were of a sub minature RS type. the mod worked perfectly.

Whilst I had the unit in pieces I also replaced the oven control relays as one was giving problems.

This was about two years ago and the unit has worked even better than new since…

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