Hi -
Our microwave died (no magic smoke-everything appears to work-just not heating food).
It was made by Sharp.
Are there any parts usable in diy audio inside???
Anything dangerous inside???
Thanks,
Our microwave died (no magic smoke-everything appears to work-just not heating food).
It was made by Sharp.
Are there any parts usable in diy audio inside???
Anything dangerous inside???
Thanks,
There are low power spot welders using microwave parts out there.
How-to: Build your own spot welder - Hack a Day
Could be handy for casework or light weight bits and pieces.
John
How-to: Build your own spot welder - Hack a Day
Could be handy for casework or light weight bits and pieces.
John
Dangerous, yes certainly! The transformer generates about 2kV.
The door 'screen' is nice perforated metal, good for making amplifier ventilation covers.
The cooling fan for cooling your amp?
The magnetron has two nice torroidal magnets... no audio use, but nice toys.
The turntable motor is also a nice toy
I'm going to save the linky to Hack A Day for later... And, I guess I'll update my Will and give it a go... 🙂
Thanks,
Thanks,
Transformer, as previously suggested. If you have two, wire 'em back to back and you have an isolation transformer (saw that tip in a magazine, IIRC).
The timer brain could be used to control something (if it functions). PC board exposure is an obvious one, but maybe you have other applications. Night light or sound to lull a rugrat to sleep? Or just use it as a digital clock.
The turntable might be useful for something.
Make a halloween display with something unpleasant rotating on the turntable (severed head? toy rats?). Make darned sure the magnetron can't possibly come back to life.
And of, course, the old rural standby: target practice out at an abandoned gravel pit. Or drop it off something high. Or fling it at a bridge abutment at speed.
The timer brain could be used to control something (if it functions). PC board exposure is an obvious one, but maybe you have other applications. Night light or sound to lull a rugrat to sleep? Or just use it as a digital clock.
The turntable might be useful for something.
Make a halloween display with something unpleasant rotating on the turntable (severed head? toy rats?). Make darned sure the magnetron can't possibly come back to life.
And of, course, the old rural standby: target practice out at an abandoned gravel pit. Or drop it off something high. Or fling it at a bridge abutment at speed.
Yes, that part can be quite dangerous without shielding, microwaves exposed to the testicals will do no good for their function.🙄 The HV transformer will carry much more current than a typical flyback transformer in a CRT circuit and can be deadly. (not that a flyback transfo can't be deadly) Other than that, you might find use for the parts so scrap away.
Although target practice isn't a bad idea.😀
Once I had a large microwave, very old, that could boil a cold cup of water in about 30-40 sec. It was powered the 220VAC line and would dim the lights.😱 It was a the real thing until the protective coating over the metal inside began to flake off and it caught fire and blew up.
Damn shame, they don't make them like that anymore. I was always a bit leary of standing right next to it during operation though.
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The transformer has a useful mass of magnet wire on bobbins which although is difficult to access can be done.
You need to attack the "E" core laminations with a masonary bolster and hammer as they are normally welded together. The welds can be split and the bobbins eventually removed.
Good for making inductors as one winding is of sufficient diameter to give low resistance
You need to attack the "E" core laminations with a masonary bolster and hammer as they are normally welded together. The welds can be split and the bobbins eventually removed.
Good for making inductors as one winding is of sufficient diameter to give low resistance
Microwave is seriously deadly, high voltage at current levels that don't just shock, they put you down. Not saying I would not poke around or scavenge a bit, but I decided on the last one, a fancy model with a keypad and display, that nothing in it was worth the risk. Too many other options for parts.
There is exactly zero risk if it is not plugged in. Well you might stab yourself with a screwdriver or give yourself a blood blister with some pliers!
There is enough copper in the transformer to make a big inductor; well worth the trouble if you are on a budget.
There is enough copper in the transformer to make a big inductor; well worth the trouble if you are on a budget.
I'm adding this as a warning,
Microwave ovens can still be lethal when unplugged.
Capacitors can remain charged to many hundreds (thousand +) volts under some fault conditions.
Hi Mooly,
I humbly retract my zero risk statement about dismantling microwave ovens. You are so right about this and I was so wrong. A Duuuuuuh moment form me>
Always be sure to discharge the capacitors inside the oven if you have just pulled the plug from the mains as the bleed resistor might have failed leaving a capacitor holding a pretty big charge.
The transformers do however contain some very useful magnet wire so it is still worth the effort.
I humbly retract my zero risk statement about dismantling microwave ovens. You are so right about this and I was so wrong. A Duuuuuuh moment form me>
Always be sure to discharge the capacitors inside the oven if you have just pulled the plug from the mains as the bleed resistor might have failed leaving a capacitor holding a pretty big charge.
The transformers do however contain some very useful magnet wire so it is still worth the effort.
Have you considered repairing it? The majority of microwave oven problems lie with the connectors to the control panel. It may only have one cheap part somewhere that has failed, or as I said, just reseating the connectors is worth a try.
One might need a KV meter with bleed off option if you attempt to discharge anything with that kind of voltage, or even just to check if there is voltage present. Keep in mind that KV potential can arc a good distance and zap you. Anyone who has ever worked on CRT's knows the danger an open flyback can present in terms of the picture tube capacitance and charge left at the anode.
This happened once in a TV repair class I took quite an age ago. A nice 32" floor model color TV had some fuses blown on the mains input. After replacing them it worked perfectly for about 10 min. Then out of the blue the flyback transfo exploded with the sound of a shotgun and flames rolled out the back. After that, it was a first year student's job to scrap any usable parts.
The teacher neglected to warn him that the tube needed to be discharged. After cutting through a few wires on the chassis, he went for the anode plug wire resulting in a 'snap' sound followed by him hitting the floor unconscious for a few moments.....zzzzZZZZTTTTTT. He got lucky and only had to hold his arm up (so the blood would return as the vein muscles were stunned) for a while. With a not so good ticker, that incident could have been fatal.
This happened once in a TV repair class I took quite an age ago. A nice 32" floor model color TV had some fuses blown on the mains input. After replacing them it worked perfectly for about 10 min. Then out of the blue the flyback transfo exploded with the sound of a shotgun and flames rolled out the back. After that, it was a first year student's job to scrap any usable parts.
The teacher neglected to warn him that the tube needed to be discharged. After cutting through a few wires on the chassis, he went for the anode plug wire resulting in a 'snap' sound followed by him hitting the floor unconscious for a few moments.....zzzzZZZZTTTTTT. He got lucky and only had to hold his arm up (so the blood would return as the vein muscles were stunned) for a while. With a not so good ticker, that incident could have been fatal.
Microwave ovens
The Capacitors in older microwaves do not have a bleed off resistor and can hold a significant charge for weeks. The most common failure to heat is a defictive diode which can be obtained cheaply from most appliance parts shops or appliance parts online. Defictive magnitrons often announce themselves by a vibration or buzzing of the tranaformer. Magnetrons are inexpensive ( $24.00 - $99.00), however, new ovens can be purchased almost as cheaply. Newer ovens use torodiadal transformers with flyback type power supplies. You should have good electronics experience before attempting to repair one. Persons have lost their lives trying. Electrical accident reports in the International Electral Inspectors Journal.
The Capacitors in older microwaves do not have a bleed off resistor and can hold a significant charge for weeks. The most common failure to heat is a defictive diode which can be obtained cheaply from most appliance parts shops or appliance parts online. Defictive magnitrons often announce themselves by a vibration or buzzing of the tranaformer. Magnetrons are inexpensive ( $24.00 - $99.00), however, new ovens can be purchased almost as cheaply. Newer ovens use torodiadal transformers with flyback type power supplies. You should have good electronics experience before attempting to repair one. Persons have lost their lives trying. Electrical accident reports in the International Electral Inspectors Journal.
Hi all
Discharching the big capacitors is a must !
For this i use an old anode cable from an old CRT.(the kind with the thick red or black insulation).
Needless to mention that you should keep your hands far enough away from the ends.
Regards
Arne
Discharching the big capacitors is a must !
For this i use an old anode cable from an old CRT.(the kind with the thick red or black insulation).
Needless to mention that you should keep your hands far enough away from the ends.
Regards
Arne
I'll be very careful. I used to work with HV electronics (magnetrons & twts-big stuff) in the USAF so I know that bad things can happen to you if you're not careful.
I think I'll just poke around and see if there's anything obviously wrong that can be repaired - if not repairable I'll just get any obviously reusable parts and junk the rest.
Interesting discussion guys, thanks,
I think I'll just poke around and see if there's anything obviously wrong that can be repaired - if not repairable I'll just get any obviously reusable parts and junk the rest.
Interesting discussion guys, thanks,
I've done just the opposite of Jerryo, cutting off the HV winding and replacing with a few turns of heavy wire (0 - 4 AWG) to make heavy-duty filament transformers - similar to the technique described in the spot-welder article...although I found no need for the winding to be helical. The few I've done were around 1 turn per volt, so getting a 5v transformer only takes 5 turns, etc. The 5v one will pull about 60 amps with no voltage sag, and the 7.5v one about 40A...great for lighting up a row of old large transmitting tubes for display.
Bud
Bud
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