Chromatography Forum

I have encountered an issue with the micromass Quattro LC. The cone voltage readback remains at zero. All other voltages and heatings (capillary voltage, desolvation, and ion block source temperature) are adjustable. After removing the source block heater, I am able to adjust the cone voltage again, and the cone readback is also correct. I suspect there may be a short circuit or leakage voltage somewhere. Is anyone familiar with this issue?

I faced a similar issue with Quattro Ultima PT. I think the source block looks similar. This is a description from my memory because we dont't have this instrument any more, so please don't expect it to be 100% accurate:
Open the cover plate of the source, then you should see the wiring to the heaters (blade connectors). In my case, these were bent up a little so they touched the front plate. Try to bend them downwards (= away from the fromt plate) and try again. It might help to put a little bit of glass wool on top of the screws for insulation.
Good luck!
Jörg

Thanks for the tip.
I had already removed the cover plate and measured it for short circuits. The resistance measurement showed approx. 13 ohms in the de-nergized state. So it doesn't seem to be due to a defective ion block heater. I will report back when I have further measurements and results. Thank you very much for now.

The solution:
The problem was caused by a defective IonBlock heater. Although the correct resistance of approx. 13 ohms can be measured at the terminals of the IonBlock heater, the insulation (sheathing of the heating wires) must have infinite resistance rather than finite resistance. With the new heater, the cone voltage is working again.

Glad to see that you found the problem. Thanks for posting the solution, this will help future users when searching the forum.