Chromatography Forum

Hello everyone having a strange issue with the Source Temp on a 6890/5973 setup. Here it goes:

After a source cleaning, during pump-down, the source temp as read by Chemstation jumped from ~80 directly to 511. I resolved this, sort of, by replacing the repeller mount and ceramic insulators.

After that it pumped down fine however the Source Temperature was fluctuating between 227-235, it is set at 230. The quad temperature is stable at 150 and unchanging. I then swapped out the feed-through board, or source wire assembly, inside the analyzer.

This is where I'm stuck. At idle all temperatures are stable, ie Source, Quad, and GC-MS interface, but at about the half-way point in the run the source temp starts to jump around from, 225 straight to 295 for example. So far Ramping the oven temp and scanning both filaments (in manual tune) have had no effect on the source temp. Neither has switching he filaments out. It seems to only occur during a run. Any advice/Thoughts?

I'd suggest a bad connection either in or to the temp sender source heater. If you have a spare source heater try swapping it out. From my experience with a dead temp sender on my 5975 quad heater they aren't cheap from Agilent and only available as the complete unit.

Update: I have replaced the IDE cable (ribbon cable) to no avail. getting the exact same responses. Does anyone know how i can verify that the side board is working properly? All the status checks from chemstation check out OK.

Thanks for the Suggestion @Steve i have replaced the heater mount, unfortunately it didn't change anything

Hello

I'd check fuses on MSD board (side).
There are checking points on MSD boards however you need board diagram to measure them (in fact points locations are on the board).

Regards

Tomasz Kubowicz

Look at the two white cloth wrapped wires that go from the Source to the pass through connector. These are the wires for the diode temperature sensor on the source. I have had these to either break a wire or the cloth to fray and cause similar intermittent problems. You can order just the temp sensor from Agilent and it is a single screw that holds it on.

It turns out I am just horribly unlucky and had two bad heater sensors. on the advice of an Agilent tech support agent I switched the connections for the quad and the source heater/sensor array. The idea being that if it is the board than the channel which receives the fault will not change, if it is the sensor it will. Although convinced it was the board, since i had already changed the sensor out, i was wrong . Thanks to all for your helpful comments and will definitely be returning when other issues crop up

Hi
We have exactly same problem. But only the temp of one heater from 150 decrease to 130 after run sequence. Did you solve your problem ?

Hi
We have exactly same problem. But only the temp of one heater from 150 decrease to 130 after run sequence. Did you solve your problem ?

If it is at the end of a sequence, check that all the methods are on the same tune file, if it loads a different method at the end that contains a tune file with the heater set to 130, then it will change the temperature to that new setting each time.

No it is not at the end of a sequence . after running 2 or 3 minutes later it starts to decrease temp not stand at a special temp untile the ms source is decrease too and not accept our commands. Then system give error in the instrument status.
We replace the heater and RTD with a new one.
It seems that transformer doesnt give anough power . The control system give max of power to the mosfet but the temp decrease.
I was confused.
Did you solve the problem?

dear friends
anybody has the same problem?
(when we start a run sequence after 2 or 3 minutes the temp of quad pole from 150 decrease to 130 .)after that we have error .
thanks

I'd suggest a bad connection either in or to the temp sender source heater. If you have a spare source heater try swapping it out. From my experience with a dead temp sender on my 5975 quad heater they aren't cheap from Agilent and only available as the complete unit.

This happened on my 5973 source heater. As in your case, it turned out to be a bad thermocouple and not cheap.