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

[Paul_A]

I’m a first-timer here on these forums so please forgive me if I’m asking the wrong question in the wrong place 🙂

I have this Bosch HBC84E653B which is around 5 years old, but the Microwave section recently started cutting out after 2 seconds. The first indication of a problem was when the cut-out tripped in the consumer unit, and that might be a clue to the fault. The conventional oven section still works fine.

My skills are around repairing audio/tv’s though I have also done a few cookers and vacuums in my time, but have little experience with microwaves, though I do know enough to understand that many of the faults relate to the magnetron.

1 new magnetron later and the fault remains.

The unit cost around £800 new and a similar replacement now will set me back around £600.

Given that this not just a cheap throw-away appliance, and has had little use, can anyone suggest the likely cause of the problem please.

As I see it, there are 3 possible culprits, the control panel, power supply and exciter board, but if I replace all three it’s going to cost me more than a new unit!

Any suggestions would be most welcome.

[electrofix]

if you changed the mag its likely the inverter has gone. when the mags alone go they don’t normally blow trips they just stop working

but don’t pay bosch prices. Bosch microwaves are based on Panasonic technology so you can get things a lot cheaper

my only word of warning is your dealing with 5000v DC and that’s lethal

Dave

[Paul_A]

Many thanks Dave..

Do you have any suggestions how I find the Panasonic equivalent to the Bosch part please..

[electrofix]

suggest you contact these guys on Ebay

https://www.ebay.co.uk/itm/Panasonic-Z606YM300BP-M3FFZZ000BP-Microwave-Inverter-PCB-Circuit-Board/350038684098?epid=2256319678&hash=item517fee71c2:g:rgcAAOSwEeFVRAHs

have not got you complete Enr number but the one I looked up used part no 647895 bosch price £129.52
to find your part not go here
https://www.bosch-home.co.uk/customer-service/care-protection-and-parts/spare-parts

Dave

[Paul_A]

Many thanks dave – fingers crossed I’ll have a working microwave again..

[Paul_A]

Back to square one I’m afraid – replaced the inverter and it’s still the same – runs for 2 seconds then stops..

So I’ve replaced the magnetron and the inverter, so can anyone suggest what I try next please..

[electrofix]

scratching my head now

assume you have checked for blown fuses as there is normally a separate fuse for the microwave section

Dave

[Paul_A]

Yes, but the microwave does come on, then shuts off, which I wouldn’t expect with a blown fuse..

Is there a way of over-riding the control panel to force the microwave to run as I guess that’s the next item..

[electrofix]

short answer to that one is no and it would not be safe

Dave

[electrofix]

difficult to know where to go from here. if it was door switches then I would not expect it to start

its the 2 secs that’s making me wonder. most of the time with mag and invertor problems it goes for about 10 till it fails

it has the makings of a board fault but can never be certain

there is one guy on ebay
https://www.ebay.co.uk/itm/Bosch-HBC…IAAOSwlGNdSsYw

you also need to check if the electronics comes with the panel

selling a control panel but you would need to check suitability. you quoted your Enr number as HBC84E653B but there are 2 more numbers after this and part will be different between models so you would also have to as him for his full Enr then go to the bosch website and check for compatibility

there is also a power board am not sure if it would cause this fault

bosch part site
https://www.bosch-home.co.uk/customer-service/care-protection-and-parts/spare-parts

Dave

[Paul_A]

After you asking if I have checked the fuse, I went back and double checked and lo and behold there was a 10a fuse blown and replacing it has restored normal operation.

A bit annoying I didn’t double check first time as that would have saved me £120 in parts I didn’t need, though I guess one of the parts I replaced might have blown the fuse.

But, I now have a piece of plastic which I can’t remember where I removed it from, so is there someware I find a layout diagram to see where it goes as I can see anywhere obvious..

[electrofix]

see bosch site above

also with the fuse blown its likely the inverter was at fault so unless there are cracks in the magnets or if it has a resistance leak to earth I would keep the mag

Dave

[Paul_A]

Many thanks again..

[electrofix]

no probs m8, glad you sorted it

its a nice feeling when you get something going

Dave

[vchook]

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

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