Is there a door interlock switch which shorts the power if the door is open (and thus blows the fuse)?

@michael8 , @Externet
seems you are right... they comment here:

https://www.ebay.co.uk/itm/204650057660
(If fuses are blowing when you close a door then the fault lies with your door switches or the door is damaged - switches not closing/opening in the correct order.)

But what does that mean ie - what is meant by door switches or what kind of door damage they are talking about?

Thanks!

 

...what kind of door damage they are talking about?...

Hinge misalignment, door plane twist, door frame bent, microswitch shifted, actuator wear or broken, debris interference, loose subassembly, microswitch internal failure, dislodged microswitch from nesting in their holder, by hit in transport, dropped ...

Did you already obtain several new fuses to start diagnosing ? The circuitry on post #20 does not include the microswitches safety interlocks.

 

what is meant by door switches

door switches = microswitches :



Nested :







---->

 

There are many interlocks and safety features in microwave ovens that would cause it not to work.

Yes, even an improperly installed door hinge would prevent it from working.

A few months ago I was asked to have a look at a microwave oven that would not heat. Apparently someone had replaced the control panel which required removing the door. During the process, the hinge got bent. I checked all the fuses, electronics, interlocks, etc. It turned that the door was misaligned, preventing the door switch from closing.

Edit: You beat me by 10 seconds. Yes, that door switch, exactly.

 

hi,
these looks like 2 switches - mostly mechanical components?

thanks

 

That’s what they are, microswitches to detect when the door is open.

 

That’s what they are, microswitches to detect when the door is open.

but is it possible to Change/ replace microswitches and not whole mechanical stuff?

 

You can install a new microswitch after you have diagnosed that it is faulty.

 

9 of 10 microwave oven fuses blown are from fast opening the door while oven is working. Microswitch contacts inertia. Hit the off/reset button instead. Buy several fuses to spare and retest.

I have also experienced this before.
Opening the door of the microwave while in operation, has caused the kitchen’s branch breaker to trip. Have experienced this several times with two different ovens so it is not a coincidence. If one shuts off the oven via the keypad it never happens.

 

You can install a new microswitch after you have diagnosed that it is faulty.

do you mean these object in Blue - that i highlighted?

 

Opening the door of the microwave while in operation, has caused the kitchen’s branch breaker to trip. Have experienced this several times with two different ovens so it is not a coincidence. If one shuts off the oven via the keypad it never happens.

thats a good point - i thought that these machines are built as you can open/close door whenever u want during the run - cheap microwaves handle this w/out issue.

 

I have also experienced this before.
Opening the door of the microwave while in operation, has caused the kitchen’s branch breaker to trip. Have experienced this several times with two different ovens so it is not a coincidence. If one shuts off the oven via the keypad it never happens.

This happened to my microwave as well. It turns out that the circuit breaker was 15 amps and would trip before the internal fuse blew. The last time that it happened the fuse blew and the microwave was dead.

I opened it up and found the blown fuse. Fortunately the manufacturer has a wire harness schematic in the machine documentation. I knew that there were a pair of redundant door switches but there was a third switch, the MONITOR SWITCH on the schematic. I had to look twice because it was clear that its function is to short AC power!

To fix the microwave, I put a layer of tape on the switch to tighten up its mount.

 

hm....

just wondering is it possible to get schematics of Miele H5040BM ?

 

My experience with Miele is that they're very tight on their documentation and repair parts. I haven't been able to find parts for the vacuum that I own. My guess is that they want their authorized repair technicians to work on them not regular consumers/owners.

 

they want their authorized repair technicians to work on them not regular consumers/owners.

unfortunately thats correct

 

Can someone validate replacement so i can order these and once technician come - detect - replace i will keep you updated.

Appreciate support!

1. diodes original RG112 & RG2110

replacement https://www.ebay.co.uk/itm/204650057660

2) capacitor

original 1.18uf 1200V

options>

1.2uf 1200V https://www.ebay.co.uk/itm/224615311437

1.1uf 1200V https://www.ebay.co.uk/itm/365567740475

3) magnetron
here - i think i cant use mode (J)
aswo.com - they told me there is replacement for 2M248H(ML) but as i am not customer they dont wanna tell me which one is it.

original Toshiba 2M248H(ML) Cant find spec of that one with (ML)

https://www.gev-online.com/en/webshop/product/403371

replacement Toshiba air-cooled magnetron 2M248J

https://www.gev-online.com/en/webshop/product/403364

4) fuse

original T12A H250V P

replacement : 12A 250V Time-lag , breaking cap 1.5kV

5) Transformer

- > in case above wont help - will have to sort out

 

Have you tested the door switch first to see whether it is the problem?

 

Have you tested the door switch first to see whether it is the problem?

I ordered Fuse, once the fuse arrive i want to execute the following test.

Insert inside cup of water, close door ; set microwave 1000W 1.5min ; run program. Once time is over, program finished. open door - measure water temp.

In case that wont work as described -> it means doors switches are OKAy, and problem is somewhere else.
Is that correct?

The reason why i want to order spares is, that in case my test wont work as expected i have to call technician - and it costs 100e just to come over to diagnose... so in case he find out something from abovementioned components is wrong he can immediately replace.

the only issue is - if he check internals and Transformer will be dead ... that its hard part.... to buy it etc...

 

You can test the door switches with a simple continuity tester on a DMM.
Unplug the microwave oven from the power outlet and test the switch contacts in open and closed position.

 

@MrChips ah good one.

There are 5 switches .... 2 have 2 pins and 3 of them have 3 pins.

Any idea how to measure these with 3 pins?