Toshiba 1550 Service Handbook page 62

Q2: Does the voltage displayed on the tester remain at 0 V?
NO
Q3: Does the heater lamp remain ON even when the voltage displayed on the tester rises above
2.5 V?
NO
Move the connectors and harnesses of J7 and the relay, and check that the voltage displayed
on the tester does not drop intermittently.
Oct. 1995 © TOSHIBA CORP.
YES
Turn off the main switch and unplug, and disconnect the heater
on PS-ACC.
Turn on the main switch (check that the heater is OFF). After
checking that the fuser unit is hot, check the following:
1 Check that J7-5 is greater than 2.5 V and less than 5V.
2 Check that J7-6 is greater than 0 V and gradually drops
over a period of time.
3 Pull out J7, then test for continuity between 5 and 6 pins
of J7 on harness, to check if the thermistor is disconnected.
4 Check for disconnection or short-circuiting around R7, R8,
R170, R28, R25, R26, R27, R29 on PWA-LGC.
YES
Turn off the main switch and unplug, and disconnect the heater
on PS-ACC.
Turn on the main switch (check that the heater is OFF). After
checking that the fuser unit is hot, check the following:
1 Check for damage, disconnection or short-circuiting
around IC6, Q1, Q3 on PWA-LGC.
2 With the signal lines harness of the SSR pulled out, does
the heater go OFF when the door switch is forcibly turned
ON and the power supply turned ON? If NO, the SSR
may be damaged. Replace the SSR and check again.
4 - 5 1550 TROUBLESHOOTING