Hey! Been working on my 1900-2. Did full recap, fixed broken indication lamps, changed rectifier. Got rid of mains hum, got back the missing left channel of the FM and it's real quiet and sounds real nice now. But there's a thing :) While switching on from stand by it thumps/pops/clicks loud in right channel, too loud to be normal. Right after turning on the green light of the FM tuning indicator (right one only) lights up for a moment, not fully but just kinda eases-in-out, and not depending on source. Does it switching on tape or phono too. While already on switching from phono to tape to any of the FM it's nice and quiet. Right channel shows DC offset around 57mV while left channel is not far from zero. Muting circuit capacitor seems to load and unload as supposed to. Any ideas where to look first? Thanks!