Cuts out in coag

Replace keypad, because it is defective

Tried the keypad, no change.  The unit still reboots in coag mode setting above 20.  This happens only when the coag is being used.   Cut mode has no problem.

Which Force 2 is it?  -1,-5,-8 PC, PCH  Please whats the serial number as there are different PSRF boards inside.

It is a force 2- 2pch.   

Serial number F9K37591T

1999 model. its done well..

Hardware first, have you checked the Cut Mode Relay,  I think it was called K2  (part number was 230007002), its the removeable transparent 4 pole relay.  This switches between cut and coag tuned circuits, it might be stuck in cut mode, check also the socket underneath and relay legs for dark carbon from sparks (Worn socket)

You might have between 2 or 4 output transistors blown.  There are 8 covering the different modes.

Has anyone taken the front nosecone apart,  the silver metalic card may have been reinstalled incorrectly, if its touching an active socket (I've seen it done) you get either a power monitor alarm or a cutout of some other kind(cant remember)

Test and Calibration  Have you performed any calibration.  HV Clamp, High Frequency Leakage, Econ, Icon, High Impedance?  

Does the system reboot with the top cover in place and if its removed? 

Thankyou.    Tried the relay.    Have not looked under it for carbon.    This only happens in coag mode, cut is fine.  Only when i complete the circuit in coag mode.  carbon on the relay socket is not an issue.  Are not the same transistors used for cut and coag, it functions in full cut mode just fine.    Cover on or off, coag past 25 is when it resets.

This happened in use, no one had touched the keyboard cable.    One minute working fine, the next not fine.   I tried it without the keyboard cable cable connected.   Same problem.

Is there an L in the coag window?  It may be in low voltage coag mode.... holding down the ready button and pressing the coag down button places it in this mode just not sure if doing the same or using the coag up takes it out of that mode.   Perhaps it is stuck in that mode.

Good to know about the  "L", however unit window is normal operating mode.