• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake
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Samsung Microwave Doesn't Heat

microo1234

Premium Member
Joined
Dec 23, 2012
Messages
4
Location
Texas
Model Number
Smh9151w
Brand
Samsung
Age
1-5 years
Was working fine heating supper when stop heating. There was not abnormal noise made. The turntable doesn't turn and magnetron fan doesn't come on anymore. I have checked main fuse, thermal fuses and interlock with ohm meter, all seem normal. Would the next procedure be to check the hi voltage diode, transformer, capacitor? What would be normal reading for these items? Does anyone have a good schematic? If parts are needed would some suggest the best cost provider? Thanks Mike
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
38,258
Location
Murray, Utah 84107, United States
How about any error codes? I doubt you would have anything on the high side would cause that kind of problem. I have a couple videos on my Facebook page how microwaves work. Part 1 is the low side and part 2 is the high side. You can view them here: Facebook I found this .pdf but I haven't found the rest of the manual.
 

Attachments

microo1234

Premium Member
Joined
Dec 23, 2012
Messages
4
Location
Texas
Continuing Investigation

How about any error codes? I doubt you would have anything on the high side would cause that kind of problem. I have a couple videos on my Facebook page how microwaves work. Part 1 is the low side and part 2 is the high side. You can view them here: Facebook I found this .pdf but I haven't found the rest of the manual.
I watched both videos, thanks. I've found that the diode is bad, out of circuit it measures nothing both ways. Capacitor measures 91uf on my meter, so I would think it's good. Magnetron measure good according to info found on this site. The transformer I question, primary measuring good, has two secondary with a combined wiring, something in common. The two red wires coming from the transformer go to the magnetron, and the white goes to the capacitor. Not sure what the measurements should be. My question is how, does the circuity with a bad diode keep the turntable from working? Maybe I have other problems? Mike
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
38,258
Location
Murray, Utah 84107, United States
If I could find a wiring diagram I could tell you. You might have more than one problem. Since the diode is connected to ground anythings possible.
 

microo1234

Premium Member
Joined
Dec 23, 2012
Messages
4
Location
Texas
Thanks again, the reason I couldn't get good reading on the transformer is I was thinking that one side of the HV goes to chassis ground. So, seems the transformer checks out good. So it seems the only problem is diode so far, unless the control board has a problem. Ordering a diode and will go from there. Mike
 

microo1234

Premium Member
Joined
Dec 23, 2012
Messages
4
Location
Texas
Got the diode today and installed, unit worked one time then diode blew. My guess is the capacitor is also bad, even though it read good on my meter. Going to order a cap and another diode and try again. Suggestions are welcome. Mike
 
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