Leakage from ageing Microwave ovens?

[ITAM805]

I'm rather reassured by the comments regarding rot, as my old Sharp is stainless steel inside and corrosion free.

[Panrock]

Looks like a new Microwave for me tomorrow then... What frequency do these things work at? I'd like to relate the wavelength to the gap size.

Steve

[Paul Stenning]

2.4GHz

[Nickthedentist]

Originally Posted by Panrock

Looks like a new Microwave for me tomorrow then...

Yes, this thread has proved educational!

As people have implied, you get what you pay for. If you can afford one with a s/s interior, then go for it.

Or look for a secondhand one if not. Some of the very best ones I've seen have been from the late 1980s from the big Japanese brands like Toshiba etc.

Nick

[paulsherwin]

My 1988 cheapo oven has no significant rust, despite being simple painted mild steel. It often gets damp as I use it to cook rice, which generates lots of steam. Rust seems to have become a much more serious problem with later models, including some relatively expensive branded ones. It's not obvious why cost cutting would cause this - maybe it's a form of deliberate built in obsolescence?

[turretslug]

Ditto, 1989, though the stupidity (or cunning...) of the internal HRC fuse popping every time that the bulb went meant that I ended up fitting a rear panel 1.25" fuseholder. Looks like I need to digest some utterances about corrosion, though!- at least it's easier and unambiguous to spot than leakage, significant or otherwise.

[ekcopyephilips]

hi all

What an interesting thread. My grandparents got a Sharp microwave in 1978. It got passed down to my mum n dad in 1988. Then i had it when i moved out in 1995. It was very basic with just an on/off button, start, defrost buttons and a mechanical timer. With a paltry 650W output. It was so heavy it made my mums worktop sag. It took two people to lift it. I took the cover off it once and there was a mahoosive transformer inside. It only ever needed a new door handle after mum dropped a bag of sugar on it. I was mesmerised by it when the engineer came to mend it,especially when he put his neon block inside the cavity and i saw it light up when he tested it after the repair. It eventually went to a second hand shop when i moved back home, its probably been long since scrapped by now, but it was a very sturdy well built item. I only ever buy Sharp or Panasonic ovens now as with something that's pumping out RF and using high voltages you don't skimp on your own safety.

[G6Tanuki]

Originally Posted by Paul Stenning

Regarding corrosion, it's always good practice to leave the door open for a few minutes after cooking to let any steam disperse and avoid condensation. I always do that and my 5 year old Sharp one which is just painted steel inside still has no signs of rust.

My current Sharp microwave starts beeping after about a minute if the door's left open. I generally don't like leaving doors on any domestic appliances open unnecessarily if only because it runs the risk of people/pets walking into them [and in the case of washing-machines/tumble-driers, smallish furry family-members actually climbing inside].

Originally Posted by Paul Stenning

2.4GHz

ISTR in the early-1980s an ARRL article on converting a microwave-oven to a high power amateur-band microwave transmitter. From memory, the pulse-modulator and components to pull and phase-lock the magnetron to a [relatively-stable] amateur-allocation frequency reference were fitted in the space where the food would normally go.

[mark pirate]

Our first microwave was bought second hand in 1982, it was built like a tank and weighed about the same!
Despite being a catering model, it was only 500W output. It was the victim of a kitchen fire in 1990 which ruined the cosmetics, so was disposed of.
Interestingly it had no turntable, the interior was stainless steel with a ceramic bottom plate. It was certainly easy to keep clean.

As for those nasty cheap ones with the painted interiors, that is where I got a turntable motor for my Panasonic from, that too had holes where the turntable wheels ran.
It was dated inside as 2007, so it did not last long. Go for a S/Steel one every time!

Mark

[line sync]

I have a Belling microwave from 1985 which is very basic with full power / defrost buttons and a clockwork timer.
This is used often and the only thing to go wrong so far was a resistor which supplies the two neon indicators on the front panel.
This oven is really well built, heavy and works well.

[vidjoman]

Our first Microwave oven was an American made Moffat. It was an early one on sale in the UK and at the time when I enquired at the local electricity board they said microwave ovens will never be allowed in the UK as they are dangerous. I bought it from somewhere else and think it cost about £300. It had 2 clockwork timers for 3 and 60 minutes. No turntable, but a stirring fan fitted in the top that ran slowly to stir the waves around the painted cavity. That was early 70's and I gave it to a family member for her shop, when I got a new one, and is still in use to heat up the pies for lunch. It was built like a tank and weighed as much.
In about 1987 I got a Sharp Carousel with touch panel, fluorescent display and stainless steel interior which is still in use today and has only ever been cleaned to remove dust and lubricate the cooling fan.

[Beobloke]

Originally Posted by Panrock

My microwave oven has rotted out at the rear - see pic. The leaking 'beam' faces away from the user into a brick wall. There is no neigbouring house nearby. It still cooks as normal. Should I be worried?

I'm sorry but, regardless of the rust, the inside of that looks like a health hazard and I wouldn't put anything I planned to eat anywhere near it!

[Brigham]

I had one of those early Moffat ovens for years. It had a distinctive mechanical tinkling sound to remind you when it was running. I kept it for ages after it was retired, hoping to make a ray-gun out of it, using cast wax lenses for focussing.

Alas, another unfinished project!

[hansomcommon]

My 1966 Toshiba ER556 ET has passed leakage tests & is still in daily use with the original magnatron. The older they are the better the quality of the seals.

[paulsherwin]

1966? I thought domestic microwave ovens were just a madman's dream then. It must have cost an absolute fortune.

[hansomcommon]

Paul, you may be right perhaps 1973, (a long time ago) The salesman gave my father a bottle of whisky to every friend he could convince to buy! It cost a small fortune then.

[paulsherwin]

They were available in the US in the 60s, where they were mostly called 'Radar Ranges'. I don't know when the Japanese started making them but I always assumed it was the early 70s. Maybe somebody who used to be in the trade has some dates.

[Panrock]

Anyway, I've taken the 'hint' and today have brought home a new Sharp R272WM. This is a close equivalent to what I had before. I looked at stainless steel interior models but they were all too big and had other features I didn't need.

Currys only had one of these in stock: the display model, and it doesn't have a user's manual. I can't find one on the Sharp site either. There is an unfamiliar digital control panel. I reckon I'll just have to puzzle it out.

Steve

[Nickthedentist]

Originally Posted by Panrock

...it doesn't have a user's manual. I can't find one on the Sharp site either. There is an unfamiliar digital control panel. I reckon I'll just have to puzzle it out.

Found it for you here, Steve:

http://www.tradenet.sharp.co.uk/file...72/R272127.pdf

But the Sharp website is RUBBISH! I found it through Google.

Nick.

[Panrock]

Nick, thanks - that's brilliant!

Your advisory service is unequalled. I still have that Panasonic 28-inch CRT set you recommended years ago - and it still works perfectly.


Steve