Questionpurchased in 1984 - yamaha c-50 control amp & m-70 power amp.(part of component rack system)
my problem is sporadic loss of sound from right speaker & sporadic static, hissing, or popping noise when i rotate volume control knob. also,
get slight static noise if i press b switch.
i can get sound back to right speaker by abruptly
rotating volume knob or pressing a & b & off switch back & forth. i used to be on A speaker output, but had same problem as B. some static
noise is heard when i press those switches.
i think i ruled out a problem with right speaker
because i connected power going to left speaker to right speaker with no problems.
i hope the problem is minor such as dust inside
volume knob or coiled speaker cable.
thanking you advance for your assistance.
AnswerDear C.D.,
Dust. Lots of it. Like 21+ years' worth.
Every component has vents which prevent the power source from overheating and damaging the rest of its innards. But the vents naturally accumulate dust. First, you need to open up both the power amplifier and preamplifier and give them a good cleaning. I recommend a low-powered, hand-held vacuum for this--NOT a househould vacuum cleaner. The latter are too powerful and can actually dislodge something you don't want loosened.
Second, get some contact cleaner at the local hi-fi store and VERY GENTLY clean the preamp's source selection knob and the balance and volume knobs and their connections. Since both the balance and volume controls alter the delivery of the sound on a sliding connection (one location and the other volume), it's important to make sure those connections are thoroughly cleaned.
As an alternative, you can take both components to your local hi-fi repair shop for a pro cleaning and, especially after 21+ years, a preventive bench test. Your choice.
My guess is that after a good cleaning your static and associated issues will be resolved.
Good luck. And thanks for choosing allexperts.com!
Kindest regards,
Kevin
