Inverter NN-T551CB, Service Manual

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or adjust without sufficient test equiptment, this circuit handles very high volatge
and current.
3. Ensure a good ground connection before beginning any troubleshooting.
4. Be careful of the high voltage circuit and take necessary precautions when
troubleshooting.
5. Discharge the high voltage capacitors on the inverter.
6. When checking the continuity of the components on the H.V. inverter circuit,
disconnect one lead wire from these parts and then check the continuity with the
AC plug removed. To do otherwise may result in a false reading or damage to your
meter. When disconnecting a plastic connector from a terminal, you must hold the
plastic connector and not the lead wire, otherwise the lead wire may become open
circuit.
7. Do not touch any parts of the circuitry on the digital programmer cicruit, since
static electric discharge may damage this control panel.
Whilst working on this board ensure that that your body is connected to ground to
discharge any static charge.
8. 240 VAC is present on the digital programmer circuit. (Terminals of the power
relays and the primary circuit of the low voltage transformer). When
troubleshooting, be cautious of possible electric shock.
Before troubleshooting, operate the microwave oven following the correct operating
procedures in the instruction manual in order to find the exact cause of any trouble,
since operator error may be mistaken for the ovens malfunction.
Figure 1
Troubleshooting (No Operation)
Figure 2
Troubleshooting (Fuse is blown)
Figure 3
Troubleshooting (Other problems)
Figure 4
Troubleshooting Inverter by Input out voltage
Figure 5