Tumble dryer 'Smart lamp' pcb

Thread Starter

notallbad

Joined Oct 14, 2019
6
This operates the drum lamp on a tumble dryer when the door is opened.
The lamp does come on but is strobing at a constant rate.

The triac is Z3M and the uc is a MB95F582K.

Is it likely the uc is stuck in reset?

Resistors, diodes and cap C1 all appear ok.

If its possible to utilise them in any way the KN1 connections are as follows:
N.C
RST
DBG
Vcc
Gnd

Any ideas please.
 

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Snail

Joined Oct 14, 2019
1
Could it be giving you an error code?
Count the number of flashes until it pauses, then look it up with model number etc
 

Thread Starter

notallbad

Joined Oct 14, 2019
6
NO, this pcb drives the drum lamp ONLY!!!

Absolutely nothing to do with the Main Control PCB which has the drying programmes.

Its called a Smart Lamp but I fail to see anything smart about it. Why not just have the lamp driven directly from the door switch which it basically depends on anyway. Open the door - lamp turns on, Close the door - lamp turns off, simple enough.
 

Thread Starter

notallbad

Joined Oct 14, 2019
6
Not sure about a timer function but quite sure that there is usually a delay between opening the door and the drum light switching on, maybe 2 secs.
 

Thread Starter

notallbad

Joined Oct 14, 2019
6
I have come across many dryers of similar and the same model number that have the 'smart lamp' pcb and that don't! Seems pointless to me. Just something else to go wrong and I have 2 of these pcb's with identical faults.
 

Thread Starter

notallbad

Joined Oct 14, 2019
6
Can't see any point in that. Come to think of it, can't really see any need for a drum light at all :).
Fixed by swapping out C4.

There is a timer function that switches the lamp off after 2 1/2 minutes or 15 secs after the door is closed, now isn't that 'Smart'!
 
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