Chromatography Forum

Hi,

I have changed the filament and the multiplier in the trap one month ago, the calibration and check air water were ok during all this time but the sensitivity was unstable. I could dectect all the compounds and I have a good base line, however when I select diagnostic I get the following message:
THE INTEGRATOR ZERO CAN NOT BE PROPERLY ADJUSTED (READS 0 ADC COUNTS WHEN SET TO MAXIMUM). LIKELY CAUSES INCLUDE:
1) EITHER R20 OR R66 ARE MISADJUSTED ON THE SAPWAVE BOARD OR 2) THE MANIFOLD ELECTRONICS ASSEMBLY IS DEFECTIVE (ELECTROMETER) OR 3) THE ELECTROMETER INPUT IS SHORTED OR 4) THE SAPWAVE BOARD IS DEFECTIVE (INTEGRATOR/LPF).
Basic Heater Test: Passed
Ionization Test: Passed
FAILED.

Any help will be very appreciated
Thanks a lot

I used to run a Varian 2000 but never run into this particular message. One hint, vent the MS and make sure there are no shorts to ground from any of your ion source components. I would thoroughly check the filament leads...using a mulitmeter once the source is removed and check nothing is physically touching to ground. Easily checked with a simple multimeter. Also make sure your electron multiplier is not touching the source block. This is a sliding mechanism that can be easily moved too far forward. Its designed to be removed easily so that you can replace the detector. Have you recently cleaning the trap? These are some of the simple things to check for a start. Timothy

Hi Sabikh,
I have had similar problems with Saturn. I needed a new SAPWAVE board in the end. I couldn't even get through the integrator zero part of the auto-calibration.
I would still try the trap cleaning procedure though first as recommended.
WK

Hi,

Thank you so much for your advices, I found that I had a shortage between the filament and the trap, I am going to change the SAPWAVE .
Thanks a lot
HS