Bosch HBC84K550B/04 Combi’ Oven/Microwave

[jontymox]

Good morning all,

I’ve brought the above oven back to my workshop, as it has a fault with the microwave.

After around 5 seconds on any microwave setting, the unit stops/aborts.

As I do very few microwaves, I’m unsure where to focus my inspection/tests for this fault, and would welcome some assistance.

Thanks in advance,

jonty

[SWERV]

I would be having a close look at the Magnetron and inverter/power module.
Check the Magnetron for an earth fault, also remove it and check that the magnets are intact and check the condition of the antenna. If it all appears fine, then the likely cause will be the Inverter.

Merv

[jontymox]

Thanks for your quick reply Merv,

Will have chance to have a look this p.m.

I’m aware about the extremely high voltage in the magnetron etc, and wonder if I can discharge it, or if a special tool is required?

jonty

[electrofix]

its will be a mag or inverter

first job
if you look at a mag and look at the connection box, there are normally air holes in it

take the cover off, disconnect the lamp and in a dim lit room operate it on full power microwave

look through the holes and your looking for a glow which is caused by the heater

if you get the then chances are its just the mag and since these units use panasonic bit it not too pricy

as for discharge, yes you need to get into the habit of doing it all the time. you just need to touch one of the mag leads to the metal chassis. you can use long well insulated screw drivers ( with a bare steel blade) hold it on the chassis and touch either of the leads. as an extra as you remove the lead touch the mag casing

voltages involved are 5000v DC plus a low voltage high current heater which is probably 6 to 12 v or so

Dave

[adv]

it was the capacitor that held the high voltage. on most i done a while back .

[electrofix]

adv wrote:it was the capacitor that held the high voltage. on most i done a while back .

its always the cap but bosch mocrowaves use an inverter board so its not like the standard transformer diode and cap situation

Dave

[adv]

its got to be the inverter board or mag .am sure my brother had one like this , he changed the inverter board still same . then changed magetron. still same .. so was about to give up . then tried a gunuine magnetron it worked . the cheaper one from connect was not good enough quality ..amen

[electrofix]

qualtex stock the gen panasonic mag 2M236M42E2

used that a lot with no problems

Dave

[jontymox]

Looks like a faulty magnetron.

However, Qualtex only show the original Bosch 642266 item, with no alternative.

Wondering if the Panasonic 2M236M42E2 is compatible, as suggested, as it is also a good price and in stock at Qualtex?

jonty

[electrofix]

what the number on the mag ?

Dave

[jontymox]

Just to confirm the number on the unit is 2M261-M32 which is in stock at Connect.

jonty

[electrofix]

Aswo also have stock at £37 plus vat and carriage
connect to me are showing £51 pls vat and carriage

or you could contact

https://www.magsells.co.uk/

Dave

[jontymox]

Alas, I’ve renewed the magnetron, and the fault remains…

There is clear cracking/damage to the magnets in the above, so I wonder if the mag’ has also damaged the inverter/power module, which looks ok visually?

However, Bosch ask nearly £200.00 for the above, which I’m sure can also be obtained cheaper.

So, I’ll contact customer and explain…

jonty

[electrofix]

yes they can be got a lot cheaper

try contacting
https://www.ebay.co.uk/str/theonestopsatshop?_trksid=p2047675.l2563

had a few of this seller

Dave

[jontymox]

Well, my customer asked me to continue and I managed to quickly obtain a inverter/power module, which I have just fitted.

Alas, the fault remains…

I can hear a relay on the module-relay board clicking on and off as expected, and now wonder if that is the cause, although Bosch would like £100.00 for this?

jonty

[Author]

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