Merrychef eikon e6 - Manual (Page 34)

E6 SERVICE MANUAL REV C 06/12
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DANGER:
BEFORE REMOVING THE OVEN CASING, ISOLATE THE
OVEN FROM THE MAINS ELECTRICITY POWER SUPPLY;
SWITCH OFF, DISCONNECT OVEN PLUG FROM WALL
SOCKET, TURN OFF ISOLATOR SWITCH TO
DISCONNECT FIXED WIRED OVENS AND LOCK-OFF.
WARNING:
ALWAYS DISCHARGE THE HT CAPACITORS BEFORE
WORKING ON THE OVEN USING A SUITABLY
INSULATED 10MΩ RESISTOR.
WARNING:
ALLOW OVEN TO COOL AND OBSERVE AND
FOLLOW ALL SAFETY PRECAUTIONS INCLUDING
THOSE DESCRIBED UNDER THE SAFETY
REGULATIONS SECTION OF THIS MANUAL BEFORE
ATTEMPTING A SERVICE OR REPAIR.
CAUTION MICROWAVE EMISSIONS:
DO NOT BECOME EXPOSED TO EMISSIONS FROM
THE MICROWAVE GENERATOR OR PARTS
CONDUCTING MICROWAVE ENERGY.
HIGH VOLTAGE COMPONENTS
High voltages and large currents are present at
the High Voltage Capacitors. It is very dangerous
to work near this part when the oven is on.
NEVER make any voltage measurements at the
High Voltage circuits, including the magnetron
filaments when connected to mains power
supply.
Even when the oven is not cooking, the High
Voltage Capacitors have High Voltages present.
Power Transformer Test
1 Disconnect and isolate the oven from the
electricity supply.
2 Allow the oven to cool down.
3 Remove the oven casing.
4 Ensure that the High Voltage Capacitors are
discharged before commencing work.
5 Remove all connections from the Power
Transformers.
6 Using a D.M.M., check the resistance of the
windings (A). Results should be as follows:
a) Mains winding (208V) across (1) and (2), between
0.5 Ω and 1.0 Ω
b) Mains winding (240V) across (1) and (3), between
0.5 Ω and 1.0 Ω
c) Mains winding to unit chassis ground or to
baseplate of transformer, making sure varnish on
baseplate is scraped at test point. Reading should
be infinite resistance.
d) High Voltage winding, across (1) and (4),
resistance reading should be infinite.
e) High Voltage winding (4) to unit chassis ground or
to baseplate of transformer, making sure varnish
on baseplate is scraped at test point, between 45 Ω
and 60 Ω.
f) Filament winding, across (5) and (6), between 0.1
Ω and 0.3 Ω.
g) Filament winding, across (1) and (5), reading
should be infinite resistance.
High Voltage Rectifier Test (Diode Board)
1 Disconnect and isolate the oven from the electricity supply.
2 Allow the oven to cool down.
3 Remove the oven casing.
4 Ensure that the High Voltage Capacitors are discharged before
commencing work.
5 Remove all connections from the High Voltage Rectifier
(diode).
6 Using an Analog Meter, test for continuity in both directions (a
then b). 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
a
b