Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Solid State => Topic started by: punkykatt on July 26, 2012, 09:09:58 pm

Title: Loud hum from boombox
Post by: punkykatt on July 26, 2012, 09:09:58 pm

Hey Guys, I have a Optiomus boombox CD/ radio/ cassette player on the bench.  Everything works fine except when you push the cassette tape play, rewind or fast forward buttons there is a loud hum in the speakers. I`m guessing its coming from the motor when its running and getting into the audio circuit some how.  Does anyone know what I can do to get rid of the hum? Thanks in advance for any input.

Title: Re: Loud hum from boombox
Post by: PRR on July 28, 2012, 09:55:48 pm

> push the cassette tape play, rewind or fast forward buttons there is a loud hum

Typically the switching shorts-out the tape head except in Play, and perhaps in FF/RW (so you can hear where you are).

So I say you have a hum in the head wires. Very likely the grounding.

You forgot to say if it also plays. One channel or both.

Title: Re: Loud hum from boombox
Post by: punkykatt on July 29, 2012, 12:18:20 pm

Thank you for the reply PRR.  Yes the tape plays, you can hear the hum behind the music.   Both channels do work.  I will have to hunt for a broken ground connection.   Thanks again.

Title: Re: Loud hum from boombox FIXED
Post by: punkykatt on July 30, 2012, 11:07:27 am

Pulled the cassette tape assembly, checked all wires for continuity and micro switch operation. All fine, plugged the mini connectors back on the board sockets, checked grounds, all fine. Put a tape in and  played it. No hum!!!! must have been a bad socket connection or crap in the micro switch?  Thanks again PRR  for having me hunt for a bad ground.