Hello.

Im new to this forum, and electronics. I wanted to fix something. I foud my amplifier that was sitting in garage. It was working great until it started to act unpredictably. The volume starts to jump and bass starts to be very poor or way to strong. The sound is very poor and crunchy. So idecided to fix it. But after week i just give up. Any ideas what can it be? Its using tda chips

 

Could be dirty rotary controls, can you post pictures of it..

 

Could be dirty rotary controls, can you post pictures of it..

Thats not the case here.. Because i just rapleced bass volume potentiometer. But its still the same :/

 

Did you measure the replacement potentiometer to see if it was smooth translations from one end to the other?

 

Did you measure the replacement potentiometer to see if it was smooth translations from one end to the other?

Yes i did.. Even the old one was good

 

Not total resistance, but between the wiper and one end while you adjust it. The reading should change smoothly. That test is easiest to see on an analog meter.

Your symptoms resemble what would have been a noisy control potentiometer. They make a contact cleaner you can use on all the front panel pots as you stated the amp was put away for a number of years. If you buy that spray, exercise the pot when you clean it. This assumes you have unplugged the amplifier from the wall outlet.

 

Not total resistance, but between the wiper and one end while you adjust it. The reading should change smoothly. That test is easiest to see on an analog meter.

Your symptoms resemble what would have been a noisy control potentiometer. They make a contact cleaner you can use on all the front panel pots as you stated the amp was put away for a number of years. If you buy that spray, exercise the pot when you clean it. This assumes you have unplugged the amplifier from the wall outlet.

Oh. Okay i will try to measure it. Maybe you can tell me how to check or capacitors are good? Maybe because they are old they are going bad? :/