Repair or Replace Microwave Oven?

My 1200W microwave oven no longer heats. Since the electronics package still works and the motorized platter turns, I presume that I need a new magnetron. How can I verify this?
In general, if we're otherwise satisfied with the oven, does it make sense to replace the magnetron? Or is the cost probably going to be at least 50% of the price of a new oven? -- Bob Simon remove both "x"s from domain for private replies
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That's like asking "My car no longer works and I think it's the transmission. Does it make sense to fix it? How the hell would anyone know without any of the relevant info? If it's a 15 year old countertop unit, you chuck it. If it's a 2 year old built in Jennaire, then you fix it. See the difference?
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Bob Simon wrote:

Hi,
Make, model#?? Counter unit, over the range style?

Local repair shop can check it out....save the service call if you bring it in.

Too little is known about your unit, some are very much worth repairing and some are not. Some older "built in" units need to be repaired as a newer one may not fit in the built in hole correctly.
jeff. Appliance Repair Aid http://www.applianceaid.com /
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Have you checked the prices of new units recently, dirt cheap.
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On Tue, 29 Mar 2005 21:52:39 GMT, "Joseph Meehan"

Thank you.
Can you give me some idea how much it might cost to replace a magnetron? For the record, the microwave is a Panasonic NN-S760WA. 1300W. Counter top unit. Manufactured in May 2000.
Before I go shopping, I'm going to take it apart and look for a blown fuse. Is there typically a big capacitor I should watch out for?
-- Bob Simon remove both "x"s from domain for private replies
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Bob Simon wrote:

I wouldn't repair a countertop microwave-only oven because a replacement is only $100-150, and keep in mind I'm so cheap that I own a 28-year-old TV I've repaired a few times.
The magnetron may be fine but something in the power supply or control circuitry may have failed. Panasonic has produced some ovens that rapidly cycle the magnetron on and off for better control of the power (most ovens simply use a relay and turn it on and off every few seconds -- not good when the cooking time is just 20 seconds), and these ovens have been much less reliable than average, maybe because a high-power triac or SCR burns out in them. I would see if Panasonic has some type of extended or secret warranty to cover these failures.
There is a large capacitor, approximately the size of a pack of cigarettes, that can store over 2,000 volts indefinitely after the AC cord has been unplugged, and it must be discharged to the chassis ground before you can safely work on the oven. See www.repairfaq.org for information. The oven's circuitry has a bleeder resistor to discharge it, but you must always assume that this resistor has failed and must manually discharge the capacitor to the chassis ground. This can be done with a plastic-handled screwdriver by connecting the bare end of a wire securely to some bare metal on the oven's chassis, wrapping the other bare end several times around the screwdriver's steel shaft, and only then touching the screwdriver blade to each of the capacitor's electrical terminals. Of course, unplug the oven from the AC before doing this, wear rubber-soled shoes, and keep one hand in your pocket to minimize the risk of completing an electrical path that goes through your heart and diaphram.
A new magnetron tube can cost as little as $35-50 (try MCM Electronics), if the oven can use a common Goldstar-style tube (even Sharps do), but may be $100 for other styles, and factory authorized suppliers may want $200. I would also replace the high voltage capacitor, high voltage diode, and thermal cut-off (mounted on magenetron), about $25 total.
The magnetron tube is held in place with bolts or nuts and has a brass braid sealing ring around its center to prevent microwaves from leaking out. Be careful not to damage this ring on the new tube, and tighten the nuts or bolts properly (not loose, not too tight, tighten all evenly) so it forms a good seal. Be sure to reconnect all the wires for the magnetron, diode, and capacitor so they don't arc and start a fire.
The magnetron is cooled by a fan, and it should be checked by disconnecting its terminals and applying the correct voltage to it. Most work at 120VAC, but some may operate from a lower voltage or even from DC. A bad fan will cause the new magnetron to burn out quickly.
Do not rely upon cheap microwave leakage detectors because they're extremely unreliable and have been known to indicate great leakage even when the magnetron was not operating or no leakage at all even when sitting inside the oven. Detectors made with liquid crystals (LCD, peel & stick against perimeter of door and against rear vent grill) or fluorescent lights are more reliable, but I don't know how sensitive the LCD type is, and the fluorescent type won't glow visibly except when the leakage is very high and the room is dim.
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Hi,

Too much if we buy it from Panasonic ;)

These units are not 1200-1300 watts...they have this high output for the first 30 seconds or so and then they cut back to approx 1000 watts for the rest of the cooking time.
Your model should have ( wouldn't come up online, might be too new ) an inverter in it = no capacitor like older models. The inverter makes the power for the magnetron and the inverters have given us much troubles. The mag should have a 5 year warranty and the rest of the unit was 2 years. Don't check for any fuses as the fuse will shut down the entire unit and not just one part of it. Don't mess too much with the inverter style microwave, take it in and have it checked if you truely want to see if it is worth repairing or not.
JMO!
jeff. Appliance Repair Aid http://www.applianceaid.com /
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I thought some magnetrons had a 5yr warrantee, look into it first. Anyway years ago a shop wanted 80$ for my repair, at 35 today you can get a cheap unit for 50- 100 a nice one. Costs have come down so much with imported that repairs are often not worth it.
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On Tue, 29 Mar 2005 17:17:40 -0600, snipped-for-privacy@webtv.net (m Ransley) wrote:

That's very interesting. I dug up the paperwork and found my Circuit City receipt dated 7/15/00. Panasonic does indeed offer a five year warranty on the magnetron, but it looks like the labor is not covered:
"Labor - one year on all parts (including, without limitations, magnetron tube). After the labor warranty has expired, the purchaser pays for all labor charges for removal and installaiton of parts (including, without limitation, magnetron tube)."
So what's the likelyhood that the problem is really a blown magnetron? Is there any test I can do with a VOM to determine if it's dead? -- Bob Simon remove both "x"s from domain for private replies
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I once had a fuse blow but it likely controled the whole unit, maybe yours has 2, open it up.
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Bob Simon wrote:

I would guess the cost is going to be more than 50% of a new oven. They are really not made to be repaired. Once they are past warrantee, repairs are usually out of the question. New ones are usually better and less expensive than you paid for the one you have.
--
Joseph Meehan

26 + 6 = 1 It's Irish Math
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You are now officially on the market ofr a new microwave.
rusty
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wrote:

clean all the microswitches, like on the door interlock. I've rescued more than one curbside microwave that way, and passed them on to broke siblings. (I'm still using my 23 year old Goldstar cheapie, mechanical timer, no turntable, damn thing won't die.)
aem sends...
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what good is that thing? so now you know for sure you nuked yourself. its too late. whats done is done.
likely all that needs to be done is to unplug the thing, remove the cover, find the ceramic fuse and replace it.
randy
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...snip...

So that you can test it for leaks after you put it back together.
Drifter "I've been here, I've been there..."
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;you snipped too much...
the main cover on the microwave that i am refering to is not a radiation shield. all of that is internal to the external case (at least on every microwave ive worked on..). its just a sheet metal cover with some paint on it.
access to the fuse i am talking about doesnt require you to remove/modify/touch any shielding.
so if you had a leaky microwave oven before you still do. if you didnt, you still dont.
randy
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I get the caution on Microwaves and anti-lock brakes. Maybe even A/C compressors. But why televisions? I have been fixing them since I was a kid both on my own and back in high school as a summer job.
No real danger here as long as you avoid or discharge the tube before poking too close. Even the tube is no killer (high voltage, low current). It gives you quite a zing that you don't forget but doesn't kill unless maybe you have a pacemaker or bad heart.
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I seem to recall a factoid that the real danger is what you hit when the tube sends you jumping away. Assuming the set isn't plugged in, you could be injured if you fell, or yanked skin across a sharp object.
Never got shocked from a picture tube, but I did - stupidly - make contact with neon sign transformer once. I swear it teleported me a good four feet. -Wm
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William wrote:

Mine experience was reaching in to grab a florescent light that had fallen into an aquarium. I never did that one again.
--
Joseph Meehan

Dia\'s Muire duit
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wrote:
When my old Sharp recently went out I went to Wal-Mart and bought a new Sharp just like the old one for $44. Not worth messing with the old one in my opinion.
J
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