Volume increasing and decreasing on preamp

I have an old B&K Reference 5 S2 preamp. I don't use the remote controller, lost it. One time my preamp increased it's volume from around -22dB to -8dB and I stopped it before it got any louder. On a Computer Audiophile forum I was told there is somany stray IR beams going around it could have been that. That was about a few weeks ago. Today it did just the opposite and went from -24dB to -40 dB. I running my music thru a MakBookPro 2013 with an ifi nano DAC using Audirvana_Plus in place of iTunes. I leave the volume control on it to almost max.I I bought the orca caps and used them on unused rca plugin on pre amp would the remedy the issue?