Source Heater Error: Timeout

The source and analyzer heaters, the wires with the beads on them, disconnected from the white ceramic source connector board should Ohm out at 14 or 15 Ohms.  They must be open to ground.

The source and analyzer PRT (Platinum Resistance Thermometers), disconnected from the white ceramic source connector board, should Ohm out at ~109 Ohms at room temperature.  The resistance goes up with heat, so if it is already warm the resistance will be higher. 

Also check the cable connections to the analyzer side board -- DO NOT unplug or plug them in to the board with the power on!!!  That will damage the instrument.

Thanks paulsalverda I'd say my thermocouple resistance for the source was definitely too low - more like 14 Ohm for that. Would a fault there prevent both zones from heating though? That's the puzzle I'm stuck on tbh. 

Thanks paulsalverda I'd say my thermocouple resistance for the source was definitely too low - more like 14 Ohm for that. Would a fault there prevent both zones from heating though? That's the puzzle I'm stuck on tbh. 

Absolutely!  If the PRT is 14 Ω instead of ~109 Ω, the system thinks the source is, oh, negative 340 degrees (joking guess), and when the heater turns on and the resistance does not change it thinks something is wrong and shuts off the heaters, both of them, for safety. If it did not, the heater could run away without control and then things get melty.

Brilliant! This is super helpful paulsalverda. Thanks for this. I'll double check that thermocouple but that makes sense.

OK, so we managed to get a replacement 5977 Ext Heater Sensor Assy and I've replaced it but still not working. Vacuum comes down as normal but neither the source nor the quad temp ramp up at all. I remeasured the resistances of the heater and the sensor on the old assy and the new one. Old one reads 13.8Ohms for the heater, new one 13.1 Ohms. Sensor reads 108 Ohms and the new one reads 110 Ohms. So, similar. I'm not getting the error I was getting before but it's not ramping the temps. I checked the fuses again (both inside the left side and the rear 250V 12.5A ones) and they all seem intact.

Main board for the MSD then?

Hi NB,

There are so many test points on mother board.

Check test point TP600 and TP602 and tell what value is showing in multimeter.

Or you can contact to your local agilent support to diagnose it...

No errors now, just not heating at all?  After waiting for good vacuum, does everything else work? Filament turns on, PFTBA valve turns on/off, ions?  Don't do this for a long time with the source cold but it won't hurt it.   Is there any chance that the main board to side board cables were plugged in with the power turned on? 

I would never recommend someone opens up the electronics module and tests voltages on the main board. There is a chance of causing problems or being hurt by the voltages present.