B&K ST 202 Plus schematics

[japon]

I'm trying to resurrect a B&K ST 202 Plus amp. Had two bad output transistors which were replaced. Put in all fuses and nothing blows on startup. Have the board I replaced the transistors on with a DC offset of 1.2 volts. The other channel reads 14 mV but runs hot. Have read that it could be the input differential pair. I do not have any documentation for this amp. Does anyone out there have anything? Thanks.

 

[thedelihaus]

I have a 202 I just picked up this weekend- would any photos help? I think you're looking for more than that, but it's what I can offer.

 

[Rootpusher]

I've owned and enjoyed a B&K Pro-10 preamp and B&K EX442 dual mono power amp for years; both Sonata series.

In my experience, B&K customer service and support of older products is exceptionally good; don't hesitate to contact them for help:

http://www.bkcomp.com/

Even though they're mostly a "home theater" company these days I got the sense from a chat with an engineer there that they have a lot of fondness for their older "audiophile" 2-channel gear.

 

[gearhound]

B&K customer service is top rate.
Twice I called up with questions....and got very quick answers.
I'm the original owner of these:
1988 B&K Pro 5 pre-amp
1988 B&K ST-140 power amp

Steve

 

[thedelihaus]

This is good to know about B&K.

I now own an ST-202 and an EX-442 Sonata, and missed out on a HT receiver by minutes a bit back.

I like dealing with companies that offer exceptional support. Another reason I'm fond of Thiel and of Vandersteen.




I would think if they still are in the business of servicing the older gear, they may not be quick to give up the schematics.



I dunno how they'll address this, but I wish you luck.

B&K is great gear.

 

[japon]

Thanks guys. sent them an email. Hope they have a schematic they can send me. Cheers!

 

[grateful]

Ohm out the driver transistors and all the rest of the parts on the blown channel. On the other channel you should see + and - .6 volts on the output transistor bases. If the channel is hot turn down the bias pot a bit.