We have a dead combi microwave.
Fisrt test - get the back off. Fortunately I have a set of security bits so can take the special screws out.
Second test - check fuse where the power comes in. This is O.K. according to my multi-meter.
Third test? Suggestions please.
Looking back I see that microwaves are supposed to be 'very fixable' but there's an awful lot of wiring in there.
TIA
Dave R
Usually, if everything works bar actually zapping anything then it's the magnetron.
Fixed one t'other month (expensive combi so better to repair than replace with a Tesco £20 one) and, before ordering a spare, tested my theory by using the 'broken' microwave to power the magnetron in situ in another microwave that was kicking about.
And lo, the mutant hybrid two microwave monster made some water warm.
A new ebay special magnetron was purchased, fitted and is working well.
Scott
Does *anything* work? If the grill works but the microwave doesn't, it could well be a problem with the micro-switches on the door - which provide a fairly complex interlock to prevent you from microwaving yourself.
If that's all you know to do, I'd leave it alone. The HV cap plus various w= iring connected to it can sometimes kill you and a whole queue of people in= an instant.
If there's no sign of life at all, first thing I'd do after discharging the= cap is check the fuse inside the microwave. If its o/c, odds are an interl= ock failure took it out. Replacing the fuse without fixing the problem is d= angerous, as the machine then has a faulty interlock plus probably an o/c s= horting resistor.
NT
and they can be extremely dangerous as well if you stick fingers in even if its been off for a while.
Brian
Not much to go wrong with a magnetron, though I have had some that were low output. However I doubt that much care is taken to make sure they will last too long when they are made, no doubt to a price. Handy magnets to keep though. Brian
Well seen no feedback hope you have not killed yourself.. Brian
It's filthy inside and new ones are cheap.
Scrap it, save the bits, make yourself a halloween ghost out of the turntable motor.
a whole queue of people in an instant.
Only if you get them to all stand in a circle holding hands...
...so I guess that's the next Hackspace meeting taken care of then!
or use it as a megger
NT
It would help a great deal if you gave the make and model so we knew what we are dealing with. Does it have a permanent display of some kind? a clock perhaps, If it has, and I assume this is also not working look for a small transformer that supplies the control panel, this will probably have its own fuse on the primary side, and a conventional bridge rectifier and smoothing cap on the secondary side.
Typically there is a relay on the control board that energises the big transformer.
Be careful.
More information. [Microwave has been sitting in the shed for a couple of years after being reported dead by No. 1 daughter.]
Combi microwave, grill, convection oven.
Cookworks brand (model unknown ATM).
After looking inside and checking the power fuse, put it back together and tested. [Getting the case back on was interesting - like early PCs before they worked out that easy removal and replacement of the case was a good idea.]
Display lights up and controls work.
On 'microwave' the light comes on, the turntable turns, but a cup of water stays cold. [So probably not a door interlock problem.]
Grill works.
Convection oven works.
So it looks like the Magnetron (wasn't that one of the Transformers?) is not working.
If I knew which internal bit it was I might be tempted to change it.
However when the new kitchen arrives it will include a built in microwave. We have a replacement simple microwave. We currently lack a grill and oven (old kitchen long gone to the scrap heap). So for the moment we will run two devices - on as a microwave and the other as an oven/grill.
I would like to repair this one just for the learning experience but lack of time will prevent me before it becomes redundant.
Some interesting large pieces of heavy metal inside, but I must resist!
Thanks for all the replies.
Cheers
Dave R
It's filthy inside and new ones are cheap.
Scrap it, save the bits, make yourself a halloween ghost out of the turntable motor.
*****************************************************************************************Cheap? £60-£100+ doesn't seem that cheap to me at the moment.
Good news: I'm putting together a wiki article on repairing microwaves. Bad news: it could be any of a list of parts Good news: without fault finding there are things that can be tried.
NT
Care to post a draft of what you've written so far?
wiring connected to it can > sometimes kill you and a whole queue of people in an instant.
Remembering that you usually say this, last time I was playing with one I went at the cap with my meter.
Flat as a flat flat thing.
I can't remember if I already had the lid off or it was in the time taken to remove the case.
That's because it has a bleed resistor.
Now take the resistor off, leave it a day and measure again.
(The last bit does depend on the dielectric. However if you have _real_ HT supplies, it's an issue.)
The bleed resistor is an integral part of the oil-filled capacitor. That's not to say that it couldn't go O/C, it's just that I have personally never known it to happen.
The circuit diagram showed the bleed resistor and, from various dire warnings, I assumed that it'd be a sufficiently large value to take ages to flatten the thing. Was surprised that it was so quick.
Scott
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.