Seimens SN46M591AU/01 shuts down s

[Newboy]

My [h=2]SN46M591AU/01 shuts down and I need to unplug to reset. It doesn’t run a cycle, it evacuates residual water and that’s about it. Insatiable thought aquastop valve have become US but tested supply and was at 20v ac. Checked wiring thinking it may be dropping voltage across a connection. No water in float chamber so float switch not activated. Managed to get 240 v ac across the aquatsop but this may have been due to altering the program, it failed to cycle then shut down and needed the disconnect reconnect to get it to power up. I’m thinking power mudule rhs replacement any other thoughts welcome[/h]

[electrofix]

when you say shut down do you mean all the display and lights go blank ?

Dave

[Newboy]

Yes it just shuts down the display and no activity within the machine. There is a voltage across the display terms as I accidentally touched the connector and got a zap

[electrofix]

make sure the rear plug is all the way home and try it in a different socket just to make sure

Dave

[Newboy]

Heater pump all good no wayward resistances found with heater, motor windings or temp sensor. Pre wash reservoir filled and conditioner tank but doesn’t evacuate from there onwards in test mode. Found outlet and regeneration solenoids to be 2.2k and 1.7 respectively, seen others tested at around 7.6k ohms the oracle YouTube . No real signs of burning on pcb except aqua stop contacts where tinned surfaces of pcb where connect two blue aqua stop wires perhaps so historical heating of solder on surfaces but not burning. Noticed whilst pre wash reservoir when powered up and in test mode a short burst of water fill and machine display goes dead and mains reset required gloat switch closed and open when should be, reed switch open and closes with magnetised screwdriver flicking past wheel and rotating sump motor pump runs and evacuates water when I’ve put some in machine with jug

[electrofix]

sounds like a main pcb power supply problem

Dave

[Newboy]

Perhaps the PTC on the board, there is a click as it shuts down like a relay, however although the panel goes blank there’s a voltage there has I accidentally found out the other day

[electrofix]

all the clicks are is the relays dropping out as the power fails

you may have a voltage on the board but chips wont work on high voltages so the power supply produces low voltage for the logic circuits

Dave

[Newboy]

So the issue was for a friends machine. As I don’t carry spares or stick for swapping out and substitution etc they got an appliance engineer in, Oz. He took the pcb out and goes it looks ok but there’s 4 boards on this unit so I could swap it and find it’s one of the others, but once the box is open it’s yours so the bill could stack up. My friend relented and paid him his $180 call out fee and still a faulty machine. Personally I thought it was shocking behaviour from the guy, what kinda skills did that demonstrate. I’m sure I could do a better job. I’m an electrician and was able to check a lot of stuff out on this machine apart from pcb. Where do I start if I want to venture down this route. I’m done with site work and I’m sure I could do as equal if not better job than this guy. Do I approach the manufacturers, is there formal training . Where can I find specialist equipment for testing programming etc

[Author]

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