• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Yamaha CA-510 dc offset problem

J

Jessy213i

New Member
Hello! First time posting ! I have a CA-510 with dc on right chanel output , moving up and down +2v -3v , i removed every transistor on the right chanel to test them out of circuit, some of them had little whiskers between the legs but all tested ok. Changed them anyway.. changed every electrolytic capacitor.The only time it disapears is when i turn the volume up halfway.. no input not load.
 

Attachments

Register to hide this ad
Jessy213i said:
Hello! First time posting ! I have a CA-510 with dc on right chanel output , moving up and down +2v -3v , i removed every transistor on the right chanel to test them out of circuit, some of them had little whiskers between the legs but all tested ok. Changed them anyway.. changed every electrolytic capacitor.The only time it disapears is when i turn the volume up halfway.. no input not load.
Click to expand...

Welcome aboard..Jessy

+/- 2-3 volts would trigger the protect circuit.
The first thing I'd look at is TR406 & TR408 differential pair.. These two should be closely matched Hfe #'s.
 
Thanks for the reply, i just checked tr406 and tr408, i had replaced them with ksa992 they are close 415 and 416 Hfe.The relay engages but i think it may be because it is ac? I just checked in ac mode and i have 3v 5.7hz . I also did a test and removed c408 and all the voltages becomes stable in the right channel.
 
Jessy213i said:
I just checked in ac mode and i have 3v 5.7hz . I also did a test and removed c408 and all the voltages becomes stable in the right channel.
Click to expand...
Do you have any sources connected ? Volume control at min. ?
 
What source is selected with the Input Select Switch on the front panel ? PHONO ? Select anything but PHONO.. The PHONO may be the source for 3 vac @ 5.7 hz.signal..
 
Jessy213i said:
Hello! First time posting ! I have a CA-510 with dc on right chanel output , moving up and down +2v -3v , i removed every transistor on the right chanel to test them out of circuit, some of them had little whiskers between the legs but all tested ok. Changed them anyway.. changed every electrolytic capacitor.The only time it disapears is when i turn the volume up halfway.. no input not load.
Click to expand...
Try cleaning your volume control.
 
You must log in or register to reply here.
Back
Top Bottom