Tonight the boss was using the old Litton microwave oven when it started making a strange rumbling. vibrating sort of sound. Before she could turn it off, it let out a big pop and let the smoke out. As you all know, things don't work well without the smoke contained within.
There has been considerable talk about things worth keeping in these old units. Any advice to someone that is lacking in electronic skills? Anything worth salvaging?
IF it is an older one with a magnetron, the magnets are good fun, very powerful. However, Harold, be very cautious of the capacitors in the power supplies, if the bleeder resistors are bad, you would not be the first one killed by a fully charged capacitor. I NEVER work on higher voltage equipment without first taking a large, well insulated screwdriver and shorting the terminals out to make sure the caps are dead. (One fellow I used to work for kept a .001mfd cap on the counter charged up to 100V. Got your attention if you picked it up and twirled it by the leads.) The current that a charged capacitor can deliver is almost infinite, duration might be short, but that might not make much difference.
On Wed, 3 Nov 2004 17:11:31 -0800, "Harold & Susan Vordos" calmly ranted:
That's true. Magic Smoke is hard to find and nearly -impossible- to put back into the box. Have you popped the cover and found the particular box from whence the smoke escaped?
wwww.Gizmos-R-Us.com has Magic Smoke Lariats for $120 if you're interested. They're a combination rope and vacuum cleaner.
I just replaced my Panasonic microwave last weekend. The arcing magnatron was putting out so much crap that it was forcing my TrippLite Internet Office UPS into overdrive every time I ran it. Wally World had a newer, hotter, nearly identical box for $74. I had the old one for over ten years, so it was time for a change. It had started to rust in the corners and wouldn't have lasted another decade even if I fixed it. I got a much easier-to-press keypad and an extra 500 watts (800-1,300) in the bargain. I'm happy.
-- Music washes away from the soul the dust of everyday life. ---- --Unknown
I'm stuck with my early/mid 80's 600W Magic Chef that won't die for nothing... gets a ton of use, and still looks good! Sure slow though...
One thing I do is always get the food out of it right away, before it has a chance to dump a lot of water vapor without the fan running. I leave the door open a little while after use too. If it does pick up a load of moisture, I wipe it out right away, and run it for 3 or 4 min at power level 'zero'... which is just the fan. (Don't think all ovens can be run at power level zero, but mine can...)
I don't know for sure if these habit's have been responsible for it's long life. However, I do know my sister leaves steaming stuff in hers all the time.... and she's been through maybe 4 or 5 oven's in the time I've had this one.
the transformer is useful for small tesla coils, the caps are good for rail guns and can crushers, there's a HV diode that comes in handy, there's the magnetron, which is probably toast, and there is the computer board which can yeild some display parts and some random discretes. the power cord is always handy, there will be fan and small"stirrer" motor -
The magnets in the old ones are great, just remove the magnets and dont take the antenna any further apart though. There should be some nice little interlock switches for the door and a relay that might come in handy. I been zapped by one of those HV caps before, it will bring a smile to your face when you get back up off the floor and realize your still alive :) Just touch a screwdriver across all the caps you see. Should also be a fairly HD rectifier in there.
What timing! I just now marketing "Replacement Smoke" just for these kind of things. I will ship a hermetrically sealed container of NEW smoke for just $9.95 per liter. Just send me your Visa or mastercard info.
All the ones I have recycled have a nice sheet of perforated steel in the door. I isolate this by drilling the spot welds, then trim away any surplus sheet. Without measuring I would say that this has slightly over 50% open area. The turntable is driven by a nice light duty gear motor. Gerry :-)} London, Canada
The new replacement unit, very inexpensive because it's only going to be used until we finish the house we're building, has one of those, but the old Litton unit doesn't have one. This thing was purchased in October of '85 for $180. There is no mention of the wattage, nor is there a turntable. I can't help but think that they were not a common feature at that time.
Not so much as a lamp got replaced during the oven's 19 + year life. I'm wondering how the new one will fare. That's some big shoes to fill.
Thanks to all for the tips and advice. I opened up the unit and found what looks like a large resistor that leads from the capacitor to ground. It was blown in half and likely accounts for the pop and smoke Susan reported. The device still runs, but pus out no heat. . The cap was fully discharged, so no danger there. A special thanks for those that brought that to my attention. I'm familiar with electrolytic caps to some degree and already knew to avoid touching them, but the advice was very much appreciated. Didn't get any farther in tearing it apart, but will do so in good time.
Tom, is there any way I can get in on the ground floor in your new venture? I have let the magic smoke out of several tools through the years, and I'm sure many other fellas have. I'm sure your product will sell like gangbusters.
Will you be creating anything for the new battery tools? They seem to have a different smoke or work on a much smaller quantity.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) email@example.com
That "large resistor" you're seeing is almost certainly actually a large diode. When that diode pukes, it frequently takes other things (most notably, the Magnetron tube that's the heart of the unit) with it. If that's the case, and from what I've seen, it usually is, it's cheaper and less painful to buy a new nuke-o-matic.