Ancient microwave oven - repairable?

[AC/HL]

The second link in the post above contains a very good safety section, well worth a read even if you've been inside one of these before.

[Boater Sam]

Fixed thousands years ago, used to re-work & re-chassis rusty ones.
I also used to train repair engineers and I will say what all of them were told on day one, YOU NEVER WORK ON A MICROWAVE THAT IS PLUGGED IN. End of.
A shorting lead should go across the capacitor as soon as the cover is off.

It may sound a bit dramatic to us guys used to working inside live sets but it is better than death, and they don't bite, they kill outright, first time.

We never lost an engineer..........................

Sam

[Red to black]

@ Dave Moll

Hi Dave, I have the TV service index and there are these articles listed.

November 1990 p45 by Nick Beer
April 1998 P404 by J LeJeune
July 1998 Also by J LeJeune Microwaves more on which refers to readers letters

I hope this may help

[matthewhouse]

A relative of my previous employer was killed by a charged microwave capacitor. Ironically he was teaching a group of appliance repairers how to repair microwave ovens, when he forgot to discharge the capacitor. Bet they didn't forget that lesson...

[Ted Kendall]

Many thanks, all.

I think it would be daft for me even to try it.

Down to the tip it goes - it's cost us £15 a year.

[ex 2 Base]

I have bought spares from CPC and they have been very helpful and replacement very quick delivery. Just a satisfied customer. Iceland and Home Base had micros for about£30 at one time. Transformer was more than £30.

[Nickthedentist]

Originally Posted by Red to black

November 1990 p45 by Nick Beer
April 1998 P404 by J LeJeune
July 1998 Also by J LeJeune Microwaves more on which refers to readers letters

I hope this may help

Those sound like the ones. Nick Beer is a member here

[trsomian]

My sister and I both bought similar microwave ovens nearly 30 years ago. Hers hummed badly one day, then stopped, so they bought a new one, and gave me the old one for bits, or whatever. It had blown the fuse. I checked the HT diode, which seemed OK, so I started dismantling it, and the HT capacitor was about the first thing I disconnected and removed. Much to my surprise it was 0 ohms. So I fitted a second hand capacitor, it worked, so I gave it back to her.

I agree though, be very careful, they are potentially killers; I would not run one without the cover on, and as others have stated, beware of stored charge in that capacitor

[Cobaltblue]

My 80's Sharpe puts the modern junk to shame.

I am wondering if it will ever go faulty

It was a lot of money back in 1987 but its been worth every penny.

In the weekday flat I have a cheepy I have to replace it every 5 years.

The Magnetron never fails, i'ts mechanical issues rust and switches.

Cheers

Mike T

[keithinuk]

I still use my old Bejam microwave on a daily basis, the new little microwaves may be cheap, but one you can fit a turkey into not so much, which I can.

[Dave Moll]

Originally Posted by Red to black

I have the TV service index and there are these articles listed.

November 1990 p45 by Nick Beer
April 1998 P404 by J LeJeune
July 1998 Also by J LeJeune Microwaves more on which refers to readers letters

That's great. I'll dig out those specific issues. I must admit that working back through the contents list of each issue was quite time-consuming - not least because I tended to stumble upon other articles of interest along the way!

[Dave Moll]

Here are the two main articles:

[Dave Moll]

... and finally, the follow-up article in June 1998 and the letter from the original author in July:

[Nickthedentist]

Well done, Dave. It was the 1990 one by our own Nick Beer that I rememeber. I only started taking the magazine in 1993 so it must have been one I read at the library. How time flies. Sorry to have sent you on a wild goose chase.

[Dave Moll]

Actually (with or without wild geese) it has been an interesting journey. I hadn't realised that Television magazine had had so much to say on the subject of microwave ovens. I also came across a couple of other interesting articles along the way.

Given the extensive archive that I now have of these and other similar magazines, there is no prospect of me finding all of the articles that may be of interest to me, so this kind of exercise causes me to focus on limited subsets - and the ability to share items of interest to others is my justification for collecting them in the first place.

[Nickthedentist]

I think Dave Sargent (an occasional poster here, and contributor to the magazine too) made an index and even scanned the articles, albeit for his own private use.

N.

[threeseven]

My 1990 Panasonic is still working well. Only issues have been a slightly broken door release button, it still works but something has obviously broken behind the panel. Also the interior lamp has failed, so far I haven't bothered to fix either!
Just today I saw a youtube vid of a faulty microwave strip down and fault find. It was an inverter type, only a few years old. It was given to the chap doing the repair by a relative, they said it went bang and stopped working. He found a blown interior lamp, the consequences of which had blown both circuit boards!! The failure sequence was, bulb blows, blows PCB fuse and another track on one PCB, this arced over to the other board which was piggy backed, track side to track side. That had put mains potential onto the piggy back board which had the microprocessor etc on it, result, scrap! If there had been an isolating sheet between the boards this would not have happened.

[electronicskip]

I remember taking the case off a microwave to change a fuse that had blown inside it years ago, and my mother wouldn't even stand in the kitchen for fear of "radiation)!!

[kirstyd]

Back in the early 70's I used to work on commercial microwaves, they were manufactured by a company called DYSONA. They were about the size of a tabletop dishwasher and weighed a ton with huge components inside compared to modern machines. The door slid up and down on runners. Food would be placed in the small aperture then the door would be pulled down and it would be held in place by an electro magnet. Once the heating process was over the magnet was switched off and the door would spring up. I remember my boss saying to me one day "In the future we won't have conventional cookers every home will have one of these instead". There was one model of this machine that had no controls just a slot rather like the one on a cash machine. Ready meals would come complete with their own card. Pop the food in the machine and the card in the slot the rest was automatic. The oven would switch off , the door would pop up and the food would slide out ready to eat. Straight out of Star trek don't you think? All this some 45 years ago.

[julie_m]

Microwave ovens are dirt cheap nowadays precisely because they are a fully-mature technology. They can churn out mechanical timers and transformers all day long; switched-mode PSUs are still not at the sweet spot of reliability vs. cost.

I'm a bit surprised no-one ever tried fitting a magnetron with a grid for power control purposes .....