Bosch HBC84E653B Combi Microwave section runs for 2 seconds before shutting off

[Paul_A]

vchook wrote:Do you mind me asking where is the fuse located as I have exactly the same problem. Thanks

Looking from the back its on the panel on the left.
On mine it was a ceramic fuse so it was difficult to tell it was blown, so you need to either test or replace it..

[electrofix]

depends on the model but most likley on the power supply panel

Dave

[vchook]

Thank you so much for the reply. A silly question, any reference on how to access to the bank panel or take the the unit out?

[electrofix]

why is this integrated ?

Dave

[vchook]

My model is actually HBC86P753B and the back panel has no easy access door so I guess I have to take it off before seeing the fuse?

[electrofix]

yes its inside looks like its on the filter panel (see pic)
have had to pic one at random as you model number lacks the last 2 digits.
you can check here yourself https://www.bosch-home.co.uk/customer-service/spare-parts-search

Dave

[vchook]

Thanks. I managed to open the back panel and I guess it’s the T8A smaller fuse that you are referring to? Thanks

[electrofix]

correct check if its blown

T stands for time delay

you should be able to get them off ebay cheaper than bosch

if it blows then you will need to find out why but beware when the microwave is working there are lethal voltages on some parts. they are well protected but, well you know where i am coming from

Dave

[vchook]

Thanks Dave, used a multi-meter to measure the existing fuse and confirmed that it is blown, so I am getting some spare T8A from Amazon, I will keep an eye on it and see whether it will blow again. Million thanks, much appreciated it.

[vchook]

Just replaced the fuse and now it’s working. Thank you so much. One more question, the fuse that I’ve got it turns out to be F8A instead of T8A of the original, are there any major differences between the two types?

[vchook]

Just read the explanation is about how fast or slow the fuse open or breaks.

[electrofix]

correct T fuse are designed not to blow on items that have an inrush of current on startup F fuses dont do this

so you may find it will blow over time so i suggest ordering the correct one so you have it if and when

Dave

[tsf]

Was really pleased to see this thread. It looks like the identical symptoms to what I am experiencing on my Bosch HBC84E653B.

After a recent power cut, the microwave now cuts off after 2/3 seconds.

But the only 2 fuses I can see both pass the continuity test. (On the left curcuit board after removing back panel.) –

[IMG2=JSON]{“data-align”:”none”,”data-size”:”full”,”height”:”1171″,”width”:”1567″,”src”:”http://52.56.111.184/fuses.jpg”}[/IMG2]

Can you advise – am I looking in the right place?

[electrofix]

they should be the correct fuses

Dave

[Nick_S]

Hi @electofix

I have just seen this same post thread from a few years ago

(https://www.ukwhitegoods.co.uk/forums/forum/public-support-forums/help-and-support/cooker-and-oven-forum/852483-bosch-hbc84e653b-combi-microwave-section-runs-for-2-seconds-before-shutting-off)

I have a similar problem with the same model, an inbuilt Bosch HBC84E653B/04 combination microwave, grill and fan oven (about 12 years old)

All functions (both the grill and fan oven) work apart from the microwave

The symptom is when you hit the start button on the microwave, it starts to count down and then stops after 3 seconds with nothing heated up.

I have checked the door safety switches and they are all OK

I have replaced the Inverter and the Magnetron with working units

I have checked the circuit board and replaced both fuses and the then the bank of relays

But the problem persists

I even found another unit on eBay and did some checks on that (also blown fuses which I replaced) and then did some major component swapping

and the problem still persists

I cannot find any information on the Initiation checks but see that failing after 3 seconds seems to be a common fault

I am in a similar situation to Paul_A in that a replacement microwave costs about £700, and a combi would be more

However that is only 1/4 of the problem as my wife wanted 4 units when they were installed 12 years ago (2 ovens, 1 combi microwave and a steamer)

Now that the combi microwave does not work and the replacement units have a different appearance – so I would have to change all 4!!! at a stupid costs if they were to look the same and all work

Do you know what else is checked in the initialisation? heat sensors etc that could be causing the microwave to fail?

thanks Nick

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