GC Temperature error.

[rikkert]

Hello guys,

Today we stumbled upon a very strange problem with our Chrompack CP9001. The temperature settings for the GC were 70 degrees for the oven, 250 for the injector and 250 for the detector.

The oven won't reach the 70 degrees however, it stays stuck on 96/95 degrees. But when I measure the temperature of the oven it is 29/30 degrees. So somehow the displayed temperature on the GC is way too high. Also the temperature isn't stable. The detector and injector temperature vary between 247 and 253 (normally it stays perfectly at 250).

Also the temperature setting for the Aux1 and Aux 2 is 0, but the actual temperature is 44 (normally it also says 0).

I think that the GC somehow displays all the temperatures too high (higher than reality) and I have no idea how this is possible.

I recently uninstalled the FID detector and installed a FPD detector (but yesterday the temperature was still OK with the FPD detector and it happened overnight).

Any help will be appreciated.

[Forse]

Sooting from the hip here: Maybe leaking/bad condensators on the board?

Condensators go bad over time, so if it is an old instrument it may be worth checking out.

[rikkert]

Hello and thank you for your response.

I have looked into the diagrams of the GC and I see that there are a lot of condensators. How do I know which one I should check? (and how can I see whether a condensator is 'bad' or in good shape?)

Thanks

[Forse]

Here are some examples.

https://www.hobbymods.com/Samsung%20tv% ... icking.htm

[rikkert]

Hello and thanks for the efforts (so far )

I have checked al the capacitors and all I could find was this:



On the image the C25 and the capacitor under the IC38 block look like they might have leaked or is this negligible? I hope one of these are causing the problem because our whole GC system is useless at the moment.

[Forse]

I dont know if they could cause your problems. Are they conected to the temperature sensing circuts?

[CE Instruments]

C25 looks to me like a paper foil capacitor not a liquid filled electrolitic.
Board swapping is so much quicker and easier although not easy with a 20+ year old GC that did not sell in huge numbers.
Sometimes it is time to put old GCs down
Do the maths, how much for a working GC second hand/new vs the time and effort to fix an old one.
If you are in a commercial environment it must be time to move on ?