Agilent 7000A GC-QQQ - MS Error 1.5

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

6 posts Page 1 of 1
Dear colleagues!

Suddenly the new problem with our Agilent 7000A GC-QQQ has appeared

Instrument has worked quite intensively for a year in our laboratory (instrument has been bought refurbished 20 month ago).
A month ago, during the analysis process, error 1.5 "Entrance lens driver cannot maintain the requested voltage" began to appear. After some time, the error is cleared and several tens of seconds it is OK, and then the same error 1.5 appears again.
At the same time the high vacuum sensor begins to give overestimated readings: normally the vacuum is ~ 5x10e-5 Torr, and at the moment when an error appears, the sensor gives 10e-8 - 10e-10 Torr on the MS display, and Mass Hunter shows only ---. When everything comes back to normal operation, the readings on the MS display and in the MH become equal and have the order of 5x10e-5
When we tried to make a ramp in Manual Tune (Ion source/Entrance lens), there was no power to the filaments. This coincided in time with incorrect readings of the high vacuum sensor. When the high vacuum sensor readings became normal, the ramp was acquired normally

What has been done:
1). Ion source has been cleaned
2). Filaments were replaced (the old ones looked good).
3). Checked the contacts of the ion source board
4). Checked lens-body short circuit - OK
5). Wires and pins - OK
6). There is no shorts between pins and body
7). Sideboards were cleaned with compressed air and vacuum cleaner (there was quite a lot of dust)

According to the service engineer, the problem was the high vacuum sensor. The high vacuum sensor gives incorrect readings that are outside the acceptable range, and the protection system turns off the power of the ion source - hence the error 1.5 (electrical supply - Entrance lens.

The high vacuum sensor has been ordered and replaced. For about five minutes after starting the MS (turbine at 100%) the high vacuum values were normal. At this moment, we acquired correct IS/Entrance lens ramp in Manual Tune and after that error 1.5 "Entrance lens driver cannot maintain the requested voltage" appeared again, the readings of the high vacuum sensor went to the 10e-8 - 10e-10 Torr unrealistic range.

Analyzing LogBook we also revealed that along with error 1.5 an error 5.1 “Firmware DSP error” also appeared periodically



What could be source of the malfunction? What else can be diagnosed?
On our 7000C we had a similar problem and I believe we had to replace the small board at the front of the side plate, where the pins pass through to the source wires. I can remember if we had to replace both the outside and inside board or only the outside one.

Not sure if that is your problem but is another thing to consider.
The past is there to guide us into the future, not to dwell in.
Hi, James_Ball!
Thank you for answering!
Do you remember if your high vacuum gauge showed incorrect readings when error 1.5 appeared?
anglerfish wrote:
Hi, James_Ball!
Thank you for answering!
Do you remember if your high vacuum gauge showed incorrect readings when error 1.5 appeared?


I don't recall any problem with the vacuum gauge, but I do know that if the reading is below 5x10e^-7 then the MH display will be only ---- even though the front of the instrument will continue reading lower values. With no flow from the column I could believe a 9x10e^-8 as mine will read in the low -7 range when the flow is below 0.5ml/min.
The past is there to guide us into the future, not to dwell in.
James_Ball wrote:
will read in the low -7 range when the flow is below 0.5ml/min.

We have low readings as well as correct readings regardless the flow. It seems that some faulty electronics misread values from the high vacuum gauge and turns off ion source.
Did you have Error 5.1 "Firmware DSP error" also?
anglerfish wrote:
James_Ball wrote:
will read in the low -7 range when the flow is below 0.5ml/min.

We have low readings as well as correct readings regardless the flow. It seems that some faulty electronics misread values from the high vacuum gauge and turns off ion source.
Did you have Error 5.1 "Firmware DSP error" also?


I have had that error before. It has to do with the Digital Signal Processor and will happen any time a signal is out of range. It usually resolves itself once the instrument can scan again. I usually get it if I adjust a setting too quickly, like when scanning and I move the repeller voltage 10v at once instead of slowly step by step.

I don't know for certain, but maybe if the ion gauge is going bad, then out of range signals being processed may be making that error appear. It might be time to replace the ion gauge at the rear of the instrument.
The past is there to guide us into the future, not to dwell in.
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