Jackson Lichfield Double Oven model 28111 – noisy Power Relay

[Oldrepairer]

This is an old cooker, probably about 1990 but is still worth repairing if possible.
The power relay on the small PCB (EC133B , 13-670L) has suddenly started to emit quite a loud vibrating noise. This occurs whenever power is applied by the rotating controls to any of the heaters eg ovens or grill. As it appeared to be a problem common to power application, as a first possibility I replaced the power relay LZ 24S.
Sadly, still noisy.
I have the problem that I cannot get a circuit diagram or block schematic for such an old cooker so diagnosis is difficult.

Has anybody thoughts on what could be the problem?

[kwatt]

There’s more or less no info on it now, no wiring but you’d never have gotten the board schematics in any event.

K.

[Oldrepairer]

Oldrepairer wrote:This is an old cooker, probably about 1990 but is still worth repairing if possible.
The power relay on the small PCB (EC133B , 13-670L) has suddenly started to emit quite a loud vibrating noise. This occurs whenever power is applied by the rotating controls to any of the heaters eg ovens or grill. As it appeared to be a problem common to power application, as a first possibility I replaced the power relay LZ 24S.
Sadly, still noisy.
I have the problem that I cannot get a circuit diagram or block schematic for such an old cooker so diagnosis is difficult.

Has anybody thoughts on what could be the problem?

An update.
I managed to obtain a used PCB and replaced the original. Problem solved. Almost certainly the problem was a failing diode on the original PCB. When tested in the positive direction, it conducted for a split second and then went open circuit ( or very high resistance) I can only assume that this was happening repetitively causing the power relay to chatter. – good for another 30 years!

[scrapheap]

Same symptoms here though not being a repairer or electrician I don’t know if they result from the same cause.
Wondering if there are any repairers in the London area who can fix – many parts seem to be available for purchase new but I doubt, if it’s a pcb, that a new one can be found; might need scavenging one or having an electronics repairman fix the existing.

[electrofix]

you could ask

https://www.qualityelectronicrepairs.co.uk/

dont know this board myself but it may be a simple fix if you can solder
would need to see s clear veiw of the board to see if i can guess which part is the most likely to fail

Dave

[Author]

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