Turbochef-technologies TurboChef User Manual download pdf (Page 45)

ISSUE RESOLUTION

F3: Magnetron

Current Low (cont.)

WARNING: Never try to check the secondary voltages of the High

Voltage Transformers.

With the top cover removed, safe access to the three (if US oven)/two (if

International oven) terminals on the top of the transformers is available.

NORTH AMERICA - Place the AC voltmeter across terminals 1+3. Press and

hold the

MGTRON soft key. Voltage present should be 240 +/- 10%.

INTERNATIONAL - Place the AC voltmeter across terminals 1+2. Press and

hold the

MGTRON soft key. Voltage present should be 230 +/- 10%.

JAPAN - Place the AC voltmeter across terminals 1+2. Press and hold the

MGTRON soft key. Voltage present should be 200 +/- 10%.

If voltage is present on both high-voltage transformers, perform the compo-

nent troubleshooting steps in the previous pages of this section.

If voltage is not present, check for 24VDC control voltage from I/O board

to the K2 relay. Access voltage reading from the "QC3" connection located

at the bottom right side of the wiring harness. When the

MGTRON key is

pressed and held, 24VDC should be present on pins 1+5. Reference the

schematics (pages 55-63) for physical location of pins on QC3 connector.

If voltage is present at the connector, inspect the K2 relay and the wiring.

Unplug the oven and replace relay if necessary.

If voltage is not present at connector, check wiring connections at the con-

trol board on the 40-pin connector. Also check the wiring between the two

connectors. Unplug the oven and replace control board if necessary.

F3 Fuse Blown Replace the F3 fuse and determine why F3 fuse opened.

Generally, the F3 fuse opens for one of three reasons:

a. HV transformer primary winding shorted: Unplug the oven and

replace the HV transformer. Follow troubleshooting on page 33 to

determine cause of failure.

b. HV capacitor shorted or failing: follow troubleshooting on page 33.

If necessary, unplug the oven and replace the HV capacitor.

NOTE: A failing HV capacitor will typically cause the HV

transformer that supplies power to the failing capacitor to draw

excessive current, which may open the F3 fuse.

THE MICROWAVE SYSTEM

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Turbochef-technologies TurboChef User Manual Page 45