B&K ST-140 Power Supply Schematic

Falcon · 12th January 2010, 03:10 AM

Hi Forum Members:
I have a B&K ST-140 that has encountered heavy distortion on both channels. It is the early version with gold letters and silver handles. The heatsinks are mounted at the exterior of the chassis.

So far I cannot be able to find any source for the schematic of the power supply section. I need to know how to bias the output transistors as well. I have two sets of Hitachi 2SK135/2SJ50 that I bought long time ago for spare. I believe I might need to replace both channels' MOSFETs.

Any help is much appreciated. Thanks in advance. So far I can only be able to obtain a copy of the main circuit schematic.

Best Regards,
Mike

h_a · 12th January 2010, 06:45 AM

The power supply should be fairly easy to trace out yourself as that's typically a linear supply.

Have fun, Hannes

12th January 2010, 03:10 AM	#1
Falcon diyAudio Member Join Date: Feb 2004 Location: Houston	B&K ST-140 Power Supply Schematic Hi Forum Members: I have a B&K ST-140 that has encountered heavy distortion on both channels. It is the early version with gold letters and silver handles. The heatsinks are mounted at the exterior of the chassis. So far I cannot be able to find any source for the schematic of the power supply section. I need to know how to bias the output transistors as well. I have two sets of Hitachi 2SK135/2SJ50 that I bought long time ago for spare. I believe I might need to replace both channels' MOSFETs. Any help is much appreciated. Thanks in advance. So far I can only be able to obtain a copy of the main circuit schematic. Best Regards, Mike

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12th January 2010, 06:45 AM	#2
h_a diyAudio Member Join Date: Sep 2006 Location: Graz, Austria	The power supply should be fairly easy to trace out yourself as that's typically a linear supply. Have fun, Hannes

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