I have a RP3 with a Ortofon 2MR hooked to SN3. Overnight, one channel has very low volume. It seems to be on the RP3 as I swapped the RCA connections and also the cartridge connectors. As the RCA connectors seem to be connected on the tone arm assembly, I’m not sure what else to do to troubleshoot. I don’t have a soldering iron either so….help! Another post with a similar issue;