Amp right side cutting out

[RideTheCrash]

My wife bought an old Kenwood KA 7300 amp for our stereo after I used a really old late 70s-early 80s silverfaced Hitachi stereo amp for a couple of years that used to be my dad's. It had an issue where one channel would start cutting out so after a while my wife picked this Kenwood up where she works for a good price.

It was fine at first but started cutting out randomly. I replaced my speaker wire and my wife insisted my speaker's were f-ed, but they are fine. She tested it before she brought it home, but this amp has a reverse, stereo and mono selector and mono will play both speakers fine, but stereo and reverse polarity can get screwy at random intervals. I also tested this with headphones. Switching the speakers physically as left and right also doesn't change the fact the right speaker will cut out.

Anyway, I realize this is an old amp. Is there some sort "easy" to way to fix this or what? I think this thing has a dual power supply or something.

 

[Minion]

There is no way of really knowing what the problem is as there are so many components in an amp and any one of them could cause several different problems when it fails...

Unless there is some physical signs inside the amp like a burnt out component or a loose or detached wire then there is no way of knowing without takeing it to a tech who has the right test equipment to figure out the problem ....

If you don"t want to spend the money to get it fixed then there are probably some good parts in the amp to build another amp ....


Cheers

 

[dgatwood]

Could it be something as simple as a bad cable feeding the right channel input or a dirty contact in the mono/stereo switch?

 

[RideTheCrash]

Hmm. The cables are fine, I replaced them and done a bunch of troubleshooting. It just happens randomly every now and then the sound will just cut out or you'll be able to hear it a little trying to kick back in. I don't think it's a dirty contact, but I could be wrong. For such an old amp, it seems like it was well taken care of.

 

[thane1200]

Hmm. The cables are fine, I replaced them and done a bunch of troubleshooting. It just happens randomly every now and then the sound will just cut out or you'll be able to hear it a little trying to kick back in. I don't think it's a dirty contact, but I could be wrong. For such an old amp, it seems like it was well taken care of.

What does tapping on the case do? Can you get any sort of reproducable issue when tapped? I had a very similar issue with and amp a few months ago.

https://homerecording.com/bbs/showthread.php?t=279171&highlight=ra300

 

[rayc]

It could be the speaker protection circuit. I had that problem with a 70's amp recently. Took a lot of finding the actual problem by a technician but a quick fix - had to be on & playing for some time before the drop out occurred & there fore could be searched for - bypassing the circuit but exposing the speakers to potential damage - & cost me a couple of hundred. The amp, a 4 channel JVC AVN880, is well worth the money - big knobs, real meters, a lovely phono circuit & gorgeous sound.
If you have a friend who's into electronics you'll be sweet otherwise you'll have to find a tech prepared to do the job & not charge too much.

 

[MCI2424]

My wife bought an old Kenwood KA 7300 amp for our stereo after I used a really old late 70s-early 80s silverfaced Hitachi stereo amp for a couple of years that used to be my dad's. It had an issue where one channel would start cutting out so after a while my wife picked this Kenwood up where she works for a good price.

It was fine at first but started cutting out randomly. I replaced my speaker wire and my wife insisted my speaker's were f-ed, but they are fine. She tested it before she brought it home, but this amp has a reverse, stereo and mono selector and mono will play both speakers fine, but stereo and reverse polarity can get screwy at random intervals. I also tested this with headphones. Switching the speakers physically as left and right also doesn't change the fact the right speaker will cut out.

Anyway, I realize this is an old amp. Is there some sort "easy" to way to fix this or what? I think this thing has a dual power supply or something.

Look for cracked solder joints. Could be anywhere from the input jack to the output jack. Most common problem.