Help with test points on KR-2600

Puddintane

AK Subscriber
Subscriber
Can someone please help me locate the test points for offset and bias on my Kenwood KR-2600. I checked the left channel at the speaker terminals the other night, and it was in the 50s range. Right now the right is hovering around 18-19mV. I don't have a service manual for this unit either. Thanks in advance for any/all help.
 
Last edited:
Offset - measure at speaker terminals. There is no adjustment pot.

Bias - measure across the emitter resistors of the outputs for each channel. Adjust to 25mvDC using Vr5,6

thumbnail_IMG_1236.jpg
 
Offset - measure at speaker terminals. There is no adjustment pot.

Bias - measure across the emitter resistors of the outputs for each channel. Adjust to 25mvDC using Vr5,6

d.png
Thanks for that image you guys. Although I confess it’s pretty hard for me to read. But if I understand it correctly, it’s directing me, for example, to what are R56 and Q18 on the circuitboard. But it’s beyond me how I get at the legs on Q18 since it looks like they’re down in there between those heat sinks or whatever they are ( and the same for 16, 15, and 17).[/QUOTE]
 

Attachments

  • 8B0E9D13-0F68-454C-B3EC-71E14EFD9FA4.jpeg
    8B0E9D13-0F68-454C-B3EC-71E14EFD9FA4.jpeg
    37.5 KB · Views: 10
  • E99698BF-DDBE-4F13-85AB-E7B756CE7FAE.jpeg
    E99698BF-DDBE-4F13-85AB-E7B756CE7FAE.jpeg
    92.8 KB · Views: 10
Last edited:
it’s pretty hard for me to read

PM me your email address and I'll send it you - then you can zoom in and actually read it. As I recall it's really tight in there - mini grabber leads for your meter are a must.

Connect to the leads shown for the big white ceramic emitter resistors R53 & R55 for the left channel and adjust VR5 to 25mv DC fully warmed up.

You only show one emitter resistor for the right (R54) channel, but connect in the same fashion to R54 & R56 for the right channel and adjust VR6 to 25mvDC.

8B0E9D13-0F68-454C-B3EC-71E14EFD9FA4.jpeg

E99698BF-DDBE-4F13-85AB-E7B756CE7FAE.jpeg
 
PM me your email address and I'll send it you - then you can zoom in and actually read it. As I recall it's really tight in there - mini grabber leads for your meter are a must.

Connect to the leads shown for the big white ceramic emitter resistors R53 & R55 for the left channel and adjust VR5 to 25mv DC fully warmed up.

You only show one emitter resistor for the right (R54) channel, but connect in the same fashion to R54 & R56 for the right channel and adjust VR6 to 25mvDC.

View attachment 1423432

View attachment 1423433
So connect to both legs of each resistor simultaneously (e.g., both legs of 53 at the same time and then the same for the rest) or across resistors (e.g., one leg on 53 and one on 55 and likewise with 54/56)?

Edit: I connected across 53/55 to the points where your arrows are and likewise across 54/56 (i.e., the outer side of each resistor) and got readings in the 40-44mV range on both sides. I adjusted them both to 25. I hope that's what you meant! Btw, do you think the offset readings are of concern (i.e., ~50mV on the right channel--see above)?
 
Last edited:
: I connected across 53/55 to the points where your arrows are and likewise across 54/56

You did it correctly

do you think the offset readings are of concern (i.e., ~50mV on the right channel--see above)

I wouldn't be concerned about it although it's not ideal. The only way to lower it is to match new differential pair transistors on that channel and I seriously doubt the difference would be audible.
 
Back
Top Bottom