2.If the coolant conductivity indicator is not lit with the probe disconnected, measure between the Logic PC Board common (TP1) and
K.Power Supply Start Circuit
NOTE
Refer to Appendix IX for Start Circuit Diagram.
The start signal enters the Merlin at
The RUN (D1) and READY (D2) leds on the Logic PC Board should be on. If The front panel TEMP led is green and the COOLANT PRESSURE led is on but READY is not on, the Logic PC Board is defective. If READY is on and RUN isn’t, check that RUN/SET/ PURGE is set to run. Measure for less than 1 VDC on the Logic PC Board
If RUN and READY are on, connect a jumper from
After the gases flow for the selected preflow time the W ON led should light and both the main contactor (W1 or W2) and PCR contactor should come on. If W ON does not light, even momentarly, the Logic PC Board is defective.
If W ON is on for a moment then off but neither W1 or W2 comes on even momentarly do the following:
The Logic PC Board has a circuit to monitor the power supply output voltage. If the circuit doesn't sense voltage in 75 ms, if the contactor doesn’t come on, it shuts off the power to the contactor which makes it hard to troublshoot. Connecting a jumper between TP4 and TP1 on the Logic PC Board disables the volt- age sensing circuit so W ON led stays on.
On the Logic PC Board, K2, sends 120 VAC to the Volt- age Selection PC Board (refer to Appendix VI). Relay K5 directs that voltage to either W1 or W2 depending on the level of incoming line voltage. If high, LED D38 on the Voltage Selection PC Board will be ON
and the 120 VAC should go to W2 otherewise it goes to W1. The first step is to measure for 120 VAC from Logic PC Board
L. Remote Control Start Circuit
NOTE
Refer to Appendix IX for Start Circuit Diagram.
The start signal from the cutting machine controller enters the RC6010 at J29 or J6 and may be either a momentary closure
If the Standoff Control (SC10) is connected, then the start signal goes to it, active low at
If the Standoff Control (SC10) is installed and the sys- tem won’t find height the problem is in the Standoff Control (SC10), Remote Control (RC6010) or the in- terconnections to the cutting machine. Set FIND HT off, it the torch starts now the problem is in the Stand- off Control (SC10).
NOTE
Refer to Section 5, Customer/Operator Service, in the Standoff Control Instruction Manual.
If it doesn’t start open the cover of either the Standoff Control (SC10) or Remote Control (RC6010), which- ever one is on top, and disconnect the ribbon cable at J5 or J7. Then if the Power Supply will start the prob-
SERVICE TROUBLESHOOTING | 26 | Manual |