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Our Hotpoint WMA36P machine died with a bang, a burning small and a blown fuse in the mains feed. Risked a fuse replacement but the machine stayed lifeless. After removing the control board and removing the soot, I can see why.
3 tracks have evaporated off the board – one from X 1 / contact 2 to S1, a second from link B18 (“GND”) partway along to the other side of S1, and the third part of the way along a thin track from R35 to a small group of SM devices.
2 other tracks have lifted off the board but are still otherwise intact – one from X1 / contact 9 to K1 and the other from X1 / contact 3 to C23.
A SM resistor (?) below the notch in the top of the board, (one end of which is tracked to the 78M05 regulator tab and hence also connected to the GND node), appears to be badly distressed and is probably dead.
So my trio of questions are:
What on earth sort of a fault could cause damage like this – anyone with the circuit diagram able to check it out or could let me sneak a peak at it?
The board is almost certainly scrap, but if it was replaced, either could there be a fault external to the board which might damage a second board or could this fault have caused any further damage in the machine?
If the board can be replaced, where can I get a replacement from please? I’ve checked out a couple of spares sites, but drawn a blank so far.
TIA for any help on this.
Re: Very sick control board from Hotpoint WMA36P
WMA standard faults – exploding door locks, wiring to motor/heater circuits chaffed through by the front concrete block. Do not even think about fitting a new board before these are checked. The door lock is cheap – replace it regardless.
Regards,
Penguin45.Re: Very sick control board from Hotpoint WMA36P
Thanks. I have put up a picture of the damaged module at http://www.wrights.me.uk/malcolm/WMA36P{e5d1b7155a01ef1f3b9c9968eaba33524ee81600d00d4be2b4d93ac2e58cec2d}20module.JPG if anyone is interested.
I’ve had a look at the door lock and it appears to be fine. On the lock, connector 2 – 3 measures about 1K, presumably a solenoid. connections 3-4 measure open circuit normally and short circuit in the locked position. Nothing appears overstressed.
The wiring to the motor etc is intact – it is strapped well away from the concrete block and appears in good condition, although I can’t unplug it from the motor to check right to the end.
A simple DC resistance check for the motor itself shows about 0.8ohm between X1-6 and X1-10 and also between X1-7 and X1-10 (1.6 ohm between X1-6 and X1-7). Also about 200ohms from X1-4 to X1-5. All other combinations between X1-10, X1-9 … X1-4 show open circuit. The 3 pairs of wires to the heater etc show 13K, 170 ohms and 30 ohms, and none of the wiring shows any leakage to ground.
Actually I have now discovered that there is a 5 year free replacement parts guarantee on this machine (it is about 3-4 years old), so perhaps I should just get the Hotpoint engineer it to fix it. Wonder how much the callout fee would compare with the cost of the module if I replace it myself?
Re: Very sick control board from Hotpoint WMA36P
Module will cost you just under Hotpoint’s labour charge. However if you replace the module on this machine it will go bang again unless you follow the good advice from P45.
That module looks to have been blown by door lock or motor, add those to the cost of the module and Hotpoint’s £90 labour charge begins to look more attractive.
Re: Very sick control board from Hotpoint WMA36P
Took the safe option and got the Hotpoint man in. He’s changed the motor as well as the module and door lock which were indeed included in the free 5 year replacement guarantee for the parts, so certainly the right decision. Thanks for the advice. 😀
Postscript – Thats only the second time if I recall correctly in some 25 years that I’ve had to “have an engineer in” to repair something like this, the other being when the Sky digibox went belly-up within its 12 month guarantee period.
We did get an “engineer” in one other time when the Central Heating broke. He decided that what we really needed was to rip the whole lot out and put in about 4 grand’s worth of new stuff which would have swelled the coffers of British Gas quite nicely I expect. I found that a £50 replacement pump did the trick pretty nicely and no need to redecorate the house afterwards. 🙂
Re: Very sick control board from Hotpoint WMA36P
PPS Actually just remembered we did get gas man in not long after we moved into our first house to check out the gas fire as there was some discolouration of the decor around it.
Turned out that visit potentially saved our lives as it transpired that the previous owners had installed this gas fire on an internal wall with no flue of any sort whatsoever. 😯
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