Advertisement
avatar: Jen1215
Jen1215
4 posts
Replied to Jen1215's post on August 8th, 2019

Hi, I have an old PE autosystem TCD im trying to get up and running. We were gifted it from another department and told it didnt work but they didnt know why.

Currenlty using helium and a detector temp of 150°C. flow rate to analytical and refernce are at 8mL/min.

 

When i try to balance the bridge is when things are going wrong. When I have set the range to any (+) number i just get a reading of -21mV, this never changes and when i try to adjust with the potentiometer absolutly nothing happens.

However when i reverse the polarity and enter a (-) range number i get a reading of about 600mV. If i leave it to settle for an hour and try to adjust the potentiometer i get i slight reduction to maybe 400mV but the manual is saying i should try to have this number down to between 0-20mV.

Ive tried backing out the detertor, this made no difference. 

I have removed the TCD board and had our electronic tech have a look, he said he could see nothing obvious but replaced some of the older looking components. After replacing the board same problem.

I also had the electronic tech check the resistance of the filaments and everything looks good there. So i think the "bridge" is intact.

Any advice would be greatly appreciated.

 

avatar: fredluis
fredluis
13 posts
Replied to Jen1215's post on August 16th, 2019

I just wanted to leave a comment to say that I enjoy your blog. Looking at the number of comments, I see others feel the same way! Congratulations on a very popular blog. tree care

avatar: Everhart
Everhart
8 posts
Replied to Jen1215's post on August 19th, 2019

I always find a gem in your new posts. Thanks for your usual wonderful effort. house painting

avatar: marahdi
marahdi
12 posts
Replied to Jen1215's post on August 19th, 2019

Look loke the resistance of detector has been changed, use the Ohm meter, loosen the connection between detector and Amplifier Board, I have a data with a good detector 

measure  between 1-2  50 ohm

measure between 1-3  50 ohm

measure betwween 1-4  around 70 ohm

measure between 2-3  70 ohm

measure between 2-4 50 ohm

measure between 3-4 50 ohm

measure at ambient temperature, 

last year i got same problem, the reading Mvi s around 200mv, I replaced with the other detector , and now is running well

 

avatar: marahdi
marahdi
12 posts
Replied to Jen1215's post on August 19th, 2019

Look loke the resistance of detector has been changed, use the Ohm meter, loosen the connection between detector and Amplifier Board, I have a data with a good detector 

measure  between 1-2  50 ohm

measure between 1-3  50 ohm

measure betwween 1-4  around 70 ohm

measure between 2-3  70 ohm

measure between 2-4 50 ohm

measure between 3-4 50 ohm

measure at ambient temperature, 

last year i got same problem, the reading Mvi s around 200mv, I replaced with the other detector , and now is running well