Buzzing from my Amplifier?

[Djanvk]

I have a Yamaha CA-810 amp and it's buzzing through the speakers no matter what input I put it on, I can't figure it out. I've disconnected and reconnected everything but can't get it out.

Any help?

 

[petehall347]

try it with speakers only

 

[Binkman]

Long shot.. have checked ac cord quality... bent pins on input output? Shut down and start up still 'buzz'?

if no scope and it's loud.. if's probably off the p.s and or ground related coming back in from one channel or another into the audio path. aside from full diagnostics a diode can have gone bad. an scr could do same. commonly found in the ps regions. or in the output.. dead short transistor not dead yet? then cut power then nothing at restart? yeah the transistor is dead and maybe some more stuff.

 

[mbz]

Are both channels affected?
Buzz still present if volume set to zero?
Tried using the 810 as a seperate, ie, do you have other gear (preamp and power amp)
so you can test the 810 pre then power stage separately

 

[NAD80]

Hello Djanvk. Welcome to AK. the Service Manual is at HiFi Engine.com. Just register and download for free. Could be in the PS.

 

[Djanvk]

Both channels are affected, and the buzz is still there with volume at zero. I did hear that is could be a bad capacitor, is that a possibility?

 

[mbz]

Yes a bad cap could cause this, so could about 5-10 other things. Most probable is in the power supply area but could be something else.
You should download the service manual, hifiengine is safe, you will need to create an account. Need some feedback on your skills level
and tools available (multimeter?, are you confident taking voltage measurements on a live amp?). As a first step you should first disconnect
the amp from all power/remove power plug and remove the outer case. Inspect what components you can, taking photo's of any suspect
parts. The main candidates are the capacitors, look for any shape distortion or leakage (not to be confused with glue). Start with the main
filter capacitors (12000uf/58V from manual)

 

[Oldsansui441]

As the guys have said above, if in both channels it is likely a bad cap on the power supply or an earthing problem.