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Good afternoon all,
The above microwave does not heat, and is randomly tripping.
I carried out several tests at my customer’s prior to bringing the unit back to my workshop, as I was/am struggling to locate the cause/s of the above.
I’ve electrically and visually tested the transformer, and magnetron, along with the high voltage capacitor and diode.
The above all appear fine.
The power module appears to be suspect, as the voltage to the transformer is very low, but thought I’d ask on here if I should be testing anything else, before ordering a new board.
jontyok first off its an isolation transformer and on side of secondary is to earth anyway so it has to be before transfomer
i would disconnect one of the wires to the transformer primary so you can play without the problems of high voltage
most likely causes of this is element and not microwave side
Dave
I’ve done some further electrical tests, as advised by electrofix (Dave) and it does appear to be a board/relay fault.
Will provide customer quote, and update.
Regards,jonty
Do you have access to the BSH order management system? they do have wiring diagrams and test procedures for each model now.
Merv
Thanks Merv,
No access to the above BSH system.
In fact, I think I’m losing my marbles 😮
I decided to take another look at the fault/s and must confess that my test meter is faulty.
I thought some of the earlier readings were odd, (Ohms resistance fine) but very low voltage to and from the board to the transformer.
As Dave rightly stated, relays are either open or closed, leading me to recheck the above with an old analogue meter – which confirms 230 odd voltage to the transformer!
So, back to the drawing board when I have time tomorrow…
jontyok that means you problems are on the high voltage side
fairly easy to diagnose that
but does not answer tripping problem as high voltage side cant cause that
Dave
Might be worth checking for a leaky high voltage capacitor.
I can download the wiring diagram and send it to you if you send your email address.Finally found the fault… severely burned magnetron antenna, although Ohms resistance tested fine at customers’ and at my workshop!
I replaced the magnetron, and after a few seconds on a microwave setting serious arcing clear to see.
Looking more closely with the magnetron removed shows arcing has burned a small hole through the cabinet casing.
jonty
jontymox wrote:Finally found the fault… severely burned magnetron antenna, although Ohms resistance tested fine at customers’ and at my workshop!
I replaced the magnetron, and after a few seconds on a microwave setting serious arcing clear to see.
Looking more closely with the magnetron removed shows arcing has burned a small hole through the cabinet casing.
jonty
you wont read any resistance reading as its just the antenna
with the hole in the casing it will probably be beyond repair
Dave
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