TROUBLESHOOTING
5-15
VersaPulse Select Service Manual
0621-499-01 12/95
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5.4.1 TURN-ON AND SHUTDOWN FAULT ISOLATION
System "turn-on" problems occur when the system fails to turn on and stay on with activation of the key switch.
System "Shutdown" refers to the system main contactor de-energizing after the system has successfully turned
on.
If the system fails to turn on, determine if there is power to the unit and through the circuit breaker to the main
contactor and isolation transformer. Determine if the main contactor is energizing when the keyswitch is held
in the start position (do the system fan and pump start running?). If not, check the circuit breaker, isolation
transformer thermal switch, front door interlock, and fuses F1/F2. If the contactor is energizing in the start
position, but de-energizing when the keyswitch is released, check for sufficient coolant flow (coolant level, pump,
line restrictions, etc.), waterflow switch S3, K2 and K1 (Refer to Interlock schematic in Section 8).
If the system shuts down after being turned on, and the circuit breaker is not tripping, use the Interlock schematic
in Section 8 to troubleshoot the main contactor interlock loop. Note that the software and main/safety processors
can not turn off the main contactor. The 24 VAC loop to the main contactor can be broken by the thermal switch
in the isolation transformer, the waterflow switch, the front door interlock switch, hold on relay K2, or the fuse
F3.
If the circuit breaker is tripping, check for proper transformer tapping. If the tripping is associated with firing (or
charging of the main capacitor), it is probably associated with the HVPS. If not, attempt to isolate the tripping
to one of the isolation transformer secondary loads by removing fuses until the circuit breaker no longer trips
(smart fan fuse, pump fuse, display P/S fuse, DC P/S fuse, then interlock loop fuse). If the breaker trips with the
isolation transformer primary side fuses removed, there is probably a problem with the HVPS or mains
components.
5.4.2 "NO FAULT CODE REPORTED" FAULT ISOLATION
Some system malfunctions cannot be reported at the Control Panel. These include those malfunctions which
interfere with the operation of the microprocessor, malfunctions in the hardware that drives the display used to
report errors, and miscellaneous circuits/functions which are not directly monitored/tested by the software.
If the malfunction is associated with a particular function (e.g., the system doesn't respond to the footswitch, or
to some front panel control), troubleshoot that function, referring to the circuit descriptions in Section 4.
If the system turns on, but the malfunction is more general (e.g., the self test sequence doesn't run, Control Panel
does not respond) check for proper DC power supply voltages, isolation transformer tapping, interconnection
problems, or for some problem with the microprocessors (are they running?)/Control Panel interface. If the
problem can not be isolated to a particular circuit, replace the CPU PCB.
5.4.3 "FAULT CODE REPORTED" FAULT ISOLATION
The safety processor monitors the system to detect and respond to various fault conditions. When a fault is
detected, the safety processor displays the fault directly on the CPU PCB (as a two digit hexadecimal number on
the two seven segment LED's) and notifies the main processor of the fault. The main processor updates the touch
screen to display the fault code and any accompanying message at the touch screen. Multiple faults are displayed
sequentially, and repeatedly.
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