hifi engine

Yamaha C-65 control amp losing right channel

I seem to have a fault in the volume control. I lose the right channel very shortly after normal operation begins. I then work the volume control up and down which produces a scratchy sound. When normal operation begins again, the right channel drops to a very low level within less than a minute.

What is the solution?

Thanks. Really wonderful site. I discovered it today.

Re: Yamaha C-65 control amp losing right channel

Hi there Buddy.

It sounds to me "sorry for Pun" like the Volume Control Potentiametor (POT) is gone dodgy. Now I dont know your level of competance at electrical repairs so forgive me please if I appear a little condensending.

It is a relatively easy repair if you take your time at it.

First thing you can do is find the schematic for it. Maybe on this wonderfull site or some other. Then you have a look at the Volume control POT specs on said schematic and discover what kind of pot is in there and its resistances from tag to tag on it.
You can then use your multimeter (if you have one) to test it.

Then you can do 1 of the following. Repalce it with new. OR. Repair the existing one.
I am confident from what you have said that the existing POT is dodgy.

So deceide what you want to do and if you need step by step advice on repair you can post back here and I will be happy to help.


Re: Yamaha C-65 control amp losing right channel

Thanks for the reply, Hotwire. You confirmed my diagnosis of a bad pot. I printed out the service manual I found on this site. I got the top cover off the amp and examined the guts within. That was when I chickened out on performing surgery. It looks like I have to remove the front cover and disassemble all of the controls to get at the problem component. That may be too big a job for my level of competence.

Re: Yamaha C-65 control amp losing right channel

MMM. Yeah I can savvy that alrite. Still, if you feel up to it then you could consider it.

I doubt if it will self heal. It will certainly get worse as time goes by. Maybe try get a replacement and have it at hand rather than opening it all up and maybe then finding the pot is Kaput and then having to leave it disambled for ages untill you get one eh.

Its happened to me with stuff. Yeah.... Then forgetting how to re-assemble. ARRGGH.

Best of luck with it anyway. Nice amp.


Re: Yamaha C-65 control amp losing right channel

Do you know where I could buy a replacement pot? I am willing to do the work. I'm handy with tools and soldering. I maintain, operate, and show a 1930 Model A Ford Deluxe Coupe, a hand built Factory Five Type 65 replica of the 1965 Shelby Daytona Coupe, and a number of 1950's Lionel O-gauge locomotives.

Yes, it is a lovely amp. I also have the Yamaha M-65 power amp and T 1020 tuner, as well as Allison four and CD 9 speakers and the Allison Electronic Subwoofer. All purchased new, and doesn't that date me!

Thanks, John.