Gain Switch Issue

I’ve had my MPC60 for a few months now and everything has been perfect. I use to sample everything with the gain switch at “LOW” and recently started sampling with it set to “MID”. Sounded perfect. The main issue is the gain switch is acting up and not recording at the same level it was this weekend. The guy I bought the sampler from did say the previous owner spilled liquid onto it but said he (the guy I bought it from) had serviced it shortly after purchasing and got the pads replaced and circuits cleaned (he said he had no issues since). The gain switch also creates a slight noise when I nudge it into the middle of “HI” and “MID”. Basically, the switch is the main issue and won’t record at the same gain it was previously. I don't know if its a grounding issue with my turntable or specifically an internal issue with the sampler. I do know I can go to a service centre and have them take a look into it. Any thoughts? While sampling a vinyl record this evening to test the issue out, the gain would jump from high to low. (While set at "MID") Thanks for all feedback.

Have you tried electronics cleaner on the switch?

Not yet. I will try that though. Any product in specific?

Dioxide read some stuff on google or watch some vids.

Thanks!!! ) will give it a try!!!! ill post what happens after the attempt.