Troubleshooting of Inverter Circuit (U) and Magnetron NEW H.V.
This oven is programmed with a self diagnostics failure code system which will help for troubleshooting. H97, H98, and H99 are the provided failure
codes to indicate magnetron and inverter circuit problem areas. This section explains failure codes of H97, H98, and H99. First, you must program
the DPC by pressing Clock , Time , Start , Power Level . Program unit for operation. H97, H98, H99 appears in display window a short time after start
key is pressed and there is no microwave oscillation.
H97, H98, or H99 appears in display window
Check magnetron filament continuity |
| Open | Magnetron* | |||
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OK | refer to componenet test |
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Check Inverter input AC voltages at |
| OV | DPC board | |||
CN702 |
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| Loose relay wiring |
AC 120V | unplug CN702 and measure |
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Check inverter control signal at |
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CN701, pin 1 and 2 |
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AC3V | unplug CN701 and measure at |
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| H.V. Inverter (U) |
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NOTE: After check, unplug unit to reset to normal operation mode. |
NOTE: DO NOT try to repair this Inverter Power Supply (U) and also DO NOT
*Check magnetron filament for open or short to casing before proceeding to determine a good magnetron.
Alternate way to troubleshoot oven with AC Ampere meter used
H97, H98, H99 appears in display window a short time after start key is pressed and no microwave oscillation with AC Ampere
meter used for troubleshooting
H97, H98, or H99 appears in display window
Check oven input AC amperes | |||
measure at oven plug |
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| more than 1A |
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| Open |
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Check | magnetron filament | ||
continuity |
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OK |
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DPC board
Loose wiring
Magnetron*
NOTE: If filament is opened, AC input Amperes 1 to 1.7A will flow
STOP!
If all the above are OK up to this point, there may be a H.
V. Inverter problem (SEE NOTE)
NOTE: DO NOT try to repair this Inverter Power Supply (U) and also DO NOT
*Check magnetron filament for open or short to casing before proceeding to determine a good magnetron.
NOTE: After check, unplug unit to reset to normal operation mode.
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