Chromatography Forum

My main workhorse GCMS 6890N mainboard died of the Thermal MUX failure on Friday. I was able to get a refurbished mainboard shipped overnight from FSA on Saturday morning. We put it in professionally, observing static protocols. The GC booted right up and all seemed great until we noticed that gas flows were not being controlled. No matter the pressure called for, the flow remained zero. This is the second time this mainboard has failed. Last year June 21 it failed and I got a brand new mainboard from Agilent. I installed it an eveything functioned perfectly. So, I am at a loss as to why this board is not controlling carrier gas pressure and flow.

Does anyone have an idea?

My main workhorse GCMS 6890N mainboard died of the Thermal MUX failure on Friday. I was able to get a refurbished mainboard shipped overnight from FSA on Saturday morning. We put it in professionally, observing static protocols. The GC booted right up and all seemed great until we noticed that gas flows were not being controlled. No matter the pressure called for, the flow remained zero. This is the second time this mainboard has failed. Last year June 21 it failed and I got a brand new mainboard from Agilent. I installed it an eveything functioned perfectly. So, I am at a loss as to why this board is not controlling carrier gas pressure and flow.

Does anyone have an idea?

Could you possibly have and EPC controller going bad (gone bad) that is damaging the mainboards?

It turned into quite a couple of weeks. I got an EPC controller card sent. But it was for an older instrument. Talked with Geof at GVTS and he sold me a working pull 6890 mainboard. That board made everything work. Apparently the problem was with the first replacement mainboard. It was booting and passing all internal tests but it was unable to actually control pressure.

Glad you got it working,

Geof is really good with those things, we had him upgrade and HPIB 5973 to LAN and still running it