Welbilt MERRYCHEF conneX Service & Repair Manual page 66

5 Service information
High voltage diode test
Ensure the following requirements have been met before starting the test:
The appliance has been disconnected from the power supply and protective measures have been taken to ensure

the power cannot be switched on again.
The appliance is cool.

The high voltage capacitors are discharged before commencing work.

See section 2.15 'How to discharge the conneX HV'
The casing of the appliance has been removed.

DANGER
High voltages and significant currents are present at the high voltage capacitor and HV Circuit.
It is very dangerous to work near this part when the oven is on.
NEVER make any electrical measurements on the high voltage circuits, including the magnetron filament, whilst the oven is
connected to the mains power supply.
High voltage capacitor test
Ensure the following requirements have been met before starting the test:
The appliance has been disconnected from the power supply and protective measures have been taken to ensure

the power cannot be switched on again.
The appliance is cool.

The high voltage capacitors are discharged before commencing work.

See section 2.15 'How to discharge the conneX HV'
The casing of the appliance has been removed.

DANGER
High voltages and significant currents are present at the high voltage capacitor and HV Circuit.
It is very dangerous to work near this part when the oven is on.
NEVER make any electrical measurements on the high voltage circuits, including the magnetron filament, whilst the oven is
connected to the mains power supply.
1. Remove all electric connections from the high voltage capacitor.
2. Using a Digital Multi-Meter (DMM), check for continuity.
Results should be as follows:
3. Connect the DMM to both terminals
of the high voltage capacitor.
The test is passed if the DMM display
reads approx. 10 MΩ.
5. Using a megger/insulation tester, test the insulation resistance between both
terminals and the metal outer case of the high voltage capacitor.
The test is passed if the megger/insulation tester display reads over 100 MΩ.
Merrychef conneX ® service and repair manual
1. Remove both connections from the high voltage diode.
2. Using a megger/insulation tester, test for continuity in both
directions.
Results should be as follows:
Open circuit both ways - FAIL
Conducts one-way only - PASS
Short circuit both ways - FAIL
Conducts one way, leaks the other – FAIL
4. Connect the DMM to one terminal and the metal outer case
of the high voltage capacitor.
The test is passed if the DMM display reads "open circuit".
Repeat the test for the other terminal and the metal outer case.
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