Sharp SMD3070ASY Service Manual page 22

SMD2470ASY
PROCEDURE
LETTER
P HIGH VOLTAGE CAPACITOR TEST
1. Disconnect the power supply cord, and then remove outer case.
2. Open the door and block it open.
3. Discharge high voltage capacitor.
4. If the capacitor is open, no high voltage will be available to the magnetron. Disconnect input leads
and check for short or open between the terminals using an ohmmeter.
Checking with a high ohm scale, if the high voltage capacitor is normal, the meter will indicate
continuity for a short time and should indicate an open circuit once the capacitor is charged. If the
above is not the case, check the capacitor with an ohmmeter to see if it is shorted between either
of the terminals and case. If it is shorted, replace the capacitor.
5. Reconnect all leads removed from components during testing.
6. Reinstall the outer case (cabinet).
7. Reconnect the power supply cord after the outer case is installed.
8. Run the oven and check all functions.
Q SWITCHING POWER SUPPLY
1. Check AC power into CN101,
if none check Main Harness.
2. Check DC power across CN201 (DC24V),
if none replace Switching Power Supply Unit
3. Check for DC getting from Switching Power Supply Unit to PSU/ CPU,
if none check Main Harness.
TEST PROCEDURES
COMPONENT TEST
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SMD3070ASY