Ricoh A-P4, Service Manual

Page: 158 / 381

543 A
Fusing overheat error (software detection) • Check harnesses and connectors of
PSU, IOB, BICU
• PSU defective
• IOB defective
• BICU defective
• Fusing thermistor defective or wrong
type
A fusing temperature of over 230 ° C
(446
o
F) is detected for 5 seconds by the
fusing thermistors at the center or at either
end of the hot roller.
544 A
Fusing overheat error (hardware circuit de-
tection) • Check harnesses and connectors of
PSU, IOB, BICU
• PSU defective
• IOB defective
• BICU defective
• Fusing thermistor defective or wrong
type
The dual monitoring circuitry of the BICU
detected temperature above 250
o
C
(482
o
F) and tripped the relay circuit off.
545 A
Fusing lamp remains on
• One or both thermistors out of posi-
tion.
After warm-up the fusing lamp remained at
full power for 10 sec. (center) and 15 sec.
(ends) without the hot roller rotating.
547 D
Zero cross signal error
• PSU defective
• Noise on the ac power line
One of the following occurred:
1. The fusing relay remained off for 50 ms
after power on and continued to re-
main off after the after 3 attempts to
detect the zero-cross signal.
2. During 11 zero-cross signal detec-
tions, two zero-cross signal detections
were below 44 Hz.
3. The zero-cross signal could not be de-
tected within 3 sec. after the fusing
relay switched on.
548 A
Fusing unit installation error
• Fusing unit is not installed
Service Call Conditions
157
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