Our stereo amplifier (1970s Rait 60-60) makes a very small and weak sound in the left channel while the right works perfectly. We've had the problem before in the past and had it repaired by a technician who said he discovered a "dry connection" which was resoldered.

Would the problem be in the control amp or the power amp? Could this be a DIY fix? We do have limited experience in simple fixes (like soldering). If it's just a faulty connection, then as long as we could be pointed in the right direction (where the faulty connection might be, what to look for) we could probably get it done. Otherwise we're not sure whether it would be worth getting it fixed by a professional (as opposed to just buying a brand new amp)?