Kenwood KR-9050

[cferry1]

Hello -

Kenwood KR-9050
After replacement of a full bank of final output power transistors.
Operating with unit vertically positioned and open, with the final output power transistor heatsink positioned vertical vs horizontal.
Curious, if you would expect the power transistors temperatures to be at any significant difference than when the heatsink is horizontal ?

 

[dstariha]

I have had to rotate and flip my amplifier when trying to bias it. It does not seem to make a difference for this purpose.
As for running it; I would guess it might run a little bit hotter, however, you said it is "open". With a couple of inches free air around it, I would suspect a few degrees rise but nothing serious.
Depends more on how hard you drive the unit than its position. Feel around with the back of your hand or use a no-touch thermometer.

 

[cferry1]

Appreciate the reply.

How many times is it suggested to adjust the Idle Current and 0 volt DC Balance on this unit after a new Final Transistor install ?

 

[dstariha]

Generally just once with most units. Assuming that the temperature sensors are correctly installed on the heat sink. I have no practical knowledge of this unit so perhaps someone else can help out.
I always check and refresh the heat paste before I try to adjust the offset and bias on any unit I run across.