I have my GC/SCD for analyzing butane samples. After I did maintenance on my pump for the SCD, I lost my signal. All I did was change and top off the oil. I was able to get a little response but the repeatability is not good. I use to get around 7000 area counts with my 10 ppm isopropyl mercaptan standard, but now I only get 2000. I tried changing both inner and outer tubes. I checked the reaction cell and the flow in the restrictor and it was good. I also just use oxygen for the ozone generator. Is there a recommended way for doing maintenance? Do I have to change everything when I do any maintenance?