MDT CASTLE 5520 Service Manual page 22

5520, 5525, & 5530 WARMING CABINETS
3. Trouble Analysis
HEATER/FAN OPERATIONAL CHECKS
も Check that circuit breaker is "ON", press the
controls "ON" switch and close the door.
Set at temperature to require heat-up of the
chamber.
DS11 and DS12 on the display PCB (printed
circuit board) should be lit. DS11 indicates the
fans are "ON" and DS12 that the heaters are
"ON."
CUT-OUT
DS12 DS11 & POWER LED (DS9)
(Other Side of PCB)
Já +
bo
J6 J7
COMPONENT LOCATIONS ON PCB
Open chamber door. DS11 and DS12 should go
out (off).
Close chamber door.
Check fan electrical supply circuit.
a. Check voltage between 2A2TB10 and
2A2SSR4 with a DVM (digital voltmeter).
Voltage should be 0 VAC with the door open
and either 120 or 240 VAC with the door
closed.
b. Place amprobe on 2A1F and 2AF2 of 2SSR4.
With the door closed, the amperage should
be 0.2A on a 120 VAC electrical supply or
0.1A on a 240 VAC electrical supply.
Check heater electrical supply circuit.
a. Check voltage between 2A2TB10 and
2A1SSR2 with a DVM. Voltage should be 0
VAC with the door open and either 120 or
240 VAC with the door closed.
b. Place amprobe on 2A4HTR and 2A3HTR or
2A1SSR2. With the door closed, the amper-
age should be 4.5A on a 120 VAC electrical
supply or 2.25A on a 240 VAC electrical
supply.
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