Microwave problem
These microwave ovens are known for bad magnetrons. Mine just failed for the second time since 2000. the first time, was after about 3 years of use. My serial number was covered under GE service bulletin RA 08-02 which
covers these microwaves from Apr 1999 through July 2000. I had a GE technician come to the house and replace the part for free (including labor). My guess is that GE got a bad lot of Magnetrons from Samsung during that time (Samsung makes the magnetrons, still does). Anyhow, when the microwave broke the second time, I decided to debug it myself. I am an electrical engineer, so I felt a little comfortable doing it. You are messing with some high voltages, so you need to be very careful. Anyow, I took the top of the microwave off (didn't have any instructions). If you can't figure out how to do this without instructions you should stop right there. You probably are not qualified to work with what is inside;)
Once you get the top off, you need to discharge the big capacitor in the front. If you let the microwave sit, it should self discharge in 30 minutes. BUT YOU SHOULD NOT COUNT ON THIS. What I did was wait 30 minutes then short the capacitor with a pair of needle nose pliers. Make sure the pliers have an insulated handle. When you do this, nothing should happen if the cap is already discharged.
The magnetron is located on the right side of the microwave. You have to remove a cover (about 3 or 4 screws) to expose it. After you do this, you should disconnect the magnetron. This is done by connecting the lower of the 2 connectors on the magnetron (the top one is a heat sensor, I think). Anyhow, after you have done that, you should ohm out between the 2 pins on the magnetron, it should be less than and ohm. After that, you should ohm between each pin and the case. This should be infinity. Mine had 500 ohms on each lead, which was bad.
If yours it bad, you should order kit WB27X10489. This kit includes the magnetron, diode, and stirrer. You should replace them all. You will see the diode on connected to one lead of the big cap. By the way, mine tested out fine. Since this is a high voltage diode, you may need to put some voltage acrossed it to test it (maybe more than a normal voltmeter provides). It you take a 1M ohm resistor and put it in series across a 12V supply, you should see it clamp at 5-6V in one direction, but not the other. Anyhow, since you are replacing it anyway, you can skip this. By the way, if the diode is really bad, you should see physcial damage on it. AND, if you do have to replace it, it will cost $40-50 dollars, but come with the magnetron anyway. The stirrer is located on the top of the microwave compartment. You have to replace it from the inside/top of the microwave compartment. You have to pop a little plastic button out, and turn it. The direction of turn to remove it are on the stirrer cover itself.
After you have replaced everything, you can test it. IMPORTANT, MAKE SURE YOU HAVE PUT ALL OF THE SCREWS BACK ON THE INSIDES BECAUSE YOU NEED TO MAKE SURE YOUR CAPACITOR HAS A SOLID PATH TO GROUND. The capacitor is mounted on a little metal plate that needs to be grounded to the main chassis. As long as you have the diode screwed to this plate, and a couple of other screws between the place and the chassis, you will be fine. If you don't you are going to see some sparks as it figures out its ground for itself.
Anyhow, if it is working after you test it, wait 30 minutes, put the cover back on, and mount it back on the wall.
BTW, the magnetron is under the 10 year magnetron warranty. HOWEVER, if you have GE come out a replace it, you are going to pay a couple hundred dollars for the SERVICE CALL plus LABOR. My kit cost around $100.
Hope this helps
