• 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

Need help on rebuilding amplifer for luxman l-85v

sorry for the late reply, I was busy and now finally I can work on my amp again.

Currently Investigating the right channel, since I am getting 52mVDC at the junction of two 82ohm resistors while left channel shows 0mVDC.
I did check the resistors and the transistors and even changed to newer components but still has the problem.

Any help will be appreciated.

thanks
 
Can you change the DC offset voltage with the Offset trim pot VR601? If you can, what are the extreme values (maybe one + and one -, be specific)?
 
hello,

I have got the VDC across the 82 ohm close to zero by adjusting the bias pot, but when I readjust the bias pot again to get the zero dc it goes to about 18mVDC

Would this be okay??


Also amp was okay until today, left channel died. I have checked by using the working right channel amplifier connected to left channel still no output.
So I am guessing that somewhere in the path of left channel is not working at all.

How should I tackle this problem

thanks for your help:)
 
UPDATE:

I have tried B speaker setting and also changing the input to AUX2, but still no output at the left channel(I do have output on the right side on any settings)
 
I have switched the fuse places, even though they all good and I got sound for few hours on both channel. But after few hours left channel died on me again.
Also if the amp is cooled off for few hours and turned up again the left channel comes back but volume is slightly less compare to right channel

Could it be the old power capacitor?
I have ordered the cap to replace 40year old cap, I will let you know once I replace them

thanks
 
Last edited:
Solved by deoxiting the mono switch and also deoxit the volume pot by drilling a hole.
All the noise when turning the volume pot went away.

Also changed the 40yr old power cap and now it is sounding even better with tighter bass.

I love working with this Amp.
Just really a great amp, hands down
 
Last edited:
hi david252 you did great job. i want to replace all the transistots on the output board can you please tell me what equivalent you used for:
2SD382
2SB537
2SC1079
2SA679
 
You must log in or register to reply here.
Back
Top Bottom