2275 DC offset

[kaplang]

The best I can get settling the DC offset is 30 mv left channel and 47mv right channel. Both R71 trimming reisistors have been replaced with comparable trimming resistors but it didn't get the 2275 DC offset any closer to 0mv.

What should I look for to get the DC offset closer to 0 mv?

George

 

[EchoWars]

Common deal with older Marantz. Need new matched differential pair transistors.

 

[kaplang]

Common deal with older Marantz. Need new matched differential pair transistors.

Thanks EchoWars.

I found a thread that lists all of the capicators and transistors needed to rebuild the main amplifier boards. I think the transistors for the differential pair is in the parts list. I think I am going to order from Mouser and give that a try.

 

[wlhd1610]

George ,
I can send you 2 pairs of hFE matched ones so you don't have to buy a boatload just to match them up.

Bob

 

[EchoWars]

Cool beans. Bob's da man.

 

[rmorano]

Diff pair as H713 and H714 or the two small trans bonded together

 

[wlhd1610]

2 bonded together.

Bob

 

[rmorano]

Thanks does anyone know the replacement part number ? 2SC1327 is obsolete I believe

 

[rBuckner]

KSC1845 would work.