Neff dishwasher dispenser not working

[zooropa]

Model number S5444X1GB.

It’s an old integrated dishwasher probably from 2009. It works well except recently the tablet dispenser tray stopped opening and I’m left with half a tablet in the dispenser at end of cycle.

Removed front door and mechanism seems to work ok by moving the plastic lever next to the actuator, the door opens and all looks good mechanically.
Did a cycle with front cover off watching for the actuator to click/move but it never did.

Across terminals of actuator measured about 2k ohm which is OK I believe. I replaced the actuator with a new one and it still doesn’t move/open the tray. Tested the voltage from 2 wires on the push in connector to actuator while dishwasher running and getting 24 v ac.

I’m suspecting there is an issue with the controller board, and due to age probably not cost effective to replace. I will continue to use dishwasher by just leaving the table tray open at start of cycle.

Any opinions on this problem welcome.

[electrofix]

i would try running it with the front cover off

that way you can watch the activator to see if it works

also if the old activator went pop inside it may have damaged the board

Dave

[zooropa]

Hi Dave,
Sorry I wasn’t clear in my post but I already tried it with the front cover removed, and I confirm the actuator (old and new doesn’t trigger) during the cycle. I think it is likely the board. When the board sends signal to activate what voltage should I be seeing on the connector?

[electrofix]

its a mains operated actuator

i think you will open the timer and find the operating triac with a hole blown out of it

Dave

[zooropa]

That makes sense, thank you. So if that’s the case I could in theory replace the triac on the PCB if I can get the details somewhere. Also the triac has sole function to send AC pulse to activate actuator to open the dispenser tray only then? That explains why the dishwasher is working fine otherwise.

[electrofix]

correct
actuator contains a heater, when switched on it extends . its not quick takes 15 seconds or so

check the feed components around the triac as they sometimes blow to. there is often other triacs with identical circuits to copy from

as long as the main chip output did not blow it should fix it

Dave

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