Lucy Electronic
- Mar 11, 2022
- 6
- Joined
- Mar 11, 2022
- Messages
- 6
My Fisher Paykel DD24 no longer detects that the drawer is closer, and subsequently won't start, giving 3 beeps and a lower tone beep. It's been on it's way out for awhile, intermittently stopping the wash cycle, been able to mitigate the issue somewhat by shimming the drawer open 5-6mm. But the other day no amount of shim would let it start.
I'm able to trigger all the functions of the dishwasher from the hardware test mode, which doesn't seem to care about the status of door. Supposedly the "keylock" symbol will appear in that mode to indicate the status of the door (but doesn't) so I'm reasonably confident in my hypothesis that the IR sensor / detector has gone bad.
They live on the main PCB which is in the drawer, and the emitter shines out to the chassis, through a lightpipe which reflects it back to the detector
The emitter and detector are separate surface mount components, I'm not sure which one is not working. I also do not have any info about the parts themselves, otherwise I'd try replacing them.
A new PCB is a few hundred dollars so I'm motivated to try a few hacks first.
I would like to trick the microcontroller, and I've thought of the following:
1) short the detector
2) solder a variable potentiometer across the detector in hopes of dialing the resistance that will cause the microcontroller to register the threshold current. (I'm assuming the normal operation is that once the detector detects IR light, it passes more current?), I may be able to use the hardware mode live and adjust the potentiometer till I see the "keylock" symbol
3) try to replace the parts, not sure where to start..
In terms of operation, I don't believe there will be much drawback to having the dish washer think the door is always closed. While in operation the lid moves down mechanically and makes the drawer difficult to open. I obviously won't try to start it while it's open either
I'm able to trigger all the functions of the dishwasher from the hardware test mode, which doesn't seem to care about the status of door. Supposedly the "keylock" symbol will appear in that mode to indicate the status of the door (but doesn't) so I'm reasonably confident in my hypothesis that the IR sensor / detector has gone bad.
They live on the main PCB which is in the drawer, and the emitter shines out to the chassis, through a lightpipe which reflects it back to the detector
The emitter and detector are separate surface mount components, I'm not sure which one is not working. I also do not have any info about the parts themselves, otherwise I'd try replacing them.
A new PCB is a few hundred dollars so I'm motivated to try a few hacks first.
I would like to trick the microcontroller, and I've thought of the following:
1) short the detector
2) solder a variable potentiometer across the detector in hopes of dialing the resistance that will cause the microcontroller to register the threshold current. (I'm assuming the normal operation is that once the detector detects IR light, it passes more current?), I may be able to use the hardware mode live and adjust the potentiometer till I see the "keylock" symbol
3) try to replace the parts, not sure where to start..
In terms of operation, I don't believe there will be much drawback to having the dish washer think the door is always closed. While in operation the lid moves down mechanically and makes the drawer difficult to open. I obviously won't try to start it while it's open either