Safety Switch Circuits - Ricoh FT5540 Service Manual

15.2 SAFETY SWITCH CIRCUITS

AC Safety Circuits
When the front door is opened, switches 1, 2, 3, and 4 open and cut ac power to the fusing
lamp and all ac components. Relay RA1 also controls ac distribution.
DC Safety Switches
Switches 7, 8, and 9, the 15-second lamp safety relay, and the fusing thermofuse will cause
RA1 to de-energize, which interrupts ac power. (Relay RA1 controls ac distribution.)
If switch 7, 8, or 9 is open, the Guidance Display indicates that a door is open. However, if
the 15-second safety relay is energized or the thermofuse fails (open circuit), the Guidance
Display will indicate a machine failure and display the appropriate Service Call Code number.
Safety switches 5 and 6 cut the 24 volts (Vp) from all power packs.
2-109
31 August 1989