Hotpoint WML730 pump / PCB problem

[Gary Sher]

Hi I was hoping for some guidance on sorting out a problem with a hotpoint WML730 washing machine.

The pump had started leaking on this and packed up. Pump was replaced with a new one but it didn’t work. Testing the new pump in isolation showed it was working fine when 240v was applied to it.

I’ve put a meter across the wiring from the PCB to the pump and this showed that only a voltage of around 130-135v was coming to the pump.

Checking the PCB circuit board showed that one of the transistors in it had “blown up” – it is the one marked as Q011 on the board and marked as Z0107NA on the transistor. The contents of the rest of the PCB looks intact. No dry joints, bulging capacitors etc..

The burned out transistor has been replaced but it has not solved the problem. The output to the pump from the PCB is still around 135v so not enough to run the pump.

Any help would be greatly appreciated in pinpointing where the problem might be.

Many thanks

Gary

[electrofix]

that little transistor is actually a Triac. It an electronic switch. these have 3 terminals A1 A2 and G. G is the trigger gate. trace the track from this and see what components are around. check all resistors back to the main chip. if you can see none then its likley the main chip has blown and you will need a new board

Dave

[andyjawa]

And if you need a brand new board the new module is blank = unprogrammed as far as I know. So that leads you to either calling out Hotpoint who will charge you vast amounts of money for an on-site visit or get the smart card and gizmo plug-in programmer reader = bigger bucks and economically crippling or get a second hand pcb off e-bay for your specific model they often sell for 35 quid so might be worth a gamble since the first 2 will cost you a fortune / be a fleecing. It`s a complete joke, except it is not funny; it is the terrible state of the trade I fear to be read as: ” Green ” it is not despite all the manufacturers BS.

[electrofix]

andyjawa wrote:And if you need a brand new board the new module is blank = unprogrammed as far as I know. So that leads you to either calling out Hotpoint who will charge you vast amounts of money for an on-site visit or get the smart card and gizmo plug-in programmer reader = bigger bucks and economically crippling or get a second hand pcb off e-bay for your specific model they often sell for 35 quid so might be worth a gamble since the first 2 will cost you a fortune / be a fleecing. It`s a complete joke, except it is not funny; it is the terrible state of the trade I fear to be read as: ” Green ” it is not despite all the manufacturers BS.

correct
it will need programming

Dave

[murv]

Check continuity of the pcb traces from the pump contacts on J004 to the triac and relay on the board. Check continuity from Q11 gate to the driver transistor just under the heatsink. If these are ok then it gets complicated as it’s all small surface mounted components. At this point I usually program a new/used board and fit it.
Murv…

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