Bad Electron Multiplier Symptoms - Thermo LTQ.

[mburleson]

Hi everyone,

I know that high voltages can indicate the multiplier(s) needs to be replaced, but I was curious what some other signs could include? I've been repairing a Thermo LTQ and cannot get steady signal. I even took our source off our working Thermo TSQ and the signal remained the same. All status readbacks of the instrument are green and should be good to go.

I've also sent the electrometer PCB to be tested by a third party and they found it to be fine. I even did the trick where you touch the anode with a metal to see if the baseline becomes awful - it did. I took that from a Thermo service manual I have.

I'm wondering if they've been exposed to atmosphere too long and that's why there is no signal? I see that Adaptas sells replacements and offers advice for cleaning the elements which I may give a try because there already isn't signal. https://www.sisweb.com/ms/detech/2312.htm#3


If anyone has any advice, it would be greatly appreciated!

[zhenfazhang]

How do you know the multiplier is the culprit? Did the diagnostics tell you that? Is there a test can be done to determine if it is good? I run into a similar problem with our TSQ where no signal whatsoever is detected, but the diagnostics indicating everything is working. Switching another working ion source to this instrument didn't help. Any idea what to check?

[mburleson]

How do you know the multiplier is the culprit? Did the diagnostics tell you that? Is there a test can be done to determine if it is good? I run into a similar problem with our TSQ where no signal whatsoever is detected, but the diagnostics indicating everything is working. Switching another working ion source to this instrument didn't help. Any idea what to check?

Our multiplier was failing its gain calibration. What diagnostics have you performed on your TSQ?

[zhenfazhang]

How do you know the multiplier is the culprit? Did the diagnostics tell you that? Is there a test can be done to determine if it is good? I run into a similar problem with our TSQ where no signal whatsoever is detected, but the diagnostics indicating everything is working. Switching another working ion source to this instrument didn't help. Any idea what to check?

Our multiplier was failing its gain calibration. What diagnostics have you performed on your TSQ?

Those diagnostics function that built into the tune mater software, like self-test.

[mburleson]

How do you know the multiplier is the culprit? Did the diagnostics tell you that? Is there a test can be done to determine if it is good? I run into a similar problem with our TSQ where no signal whatsoever is detected, but the diagnostics indicating everything is working. Switching another working ion source to this instrument didn't help. Any idea what to check?

Our multiplier was failing its gain calibration. What diagnostics have you performed on your TSQ?

Those diagnostics function that built into the tune mater software, like self-test.

Is there a way I could email you? I'd love to try and help you out.