The Dude Posted January 30, 2012 Share Posted January 30, 2012 I have been going through replaceing some of the caps on a broken down HH Scott I pick up a while back so far with just the rectifier tube in I got it to light up and the 2 led lights on the front to come on. Before I continue I would like to replace the selenium rectifier. I have read some were that once replaced with a better more efficent rectifier I would need a resistor to drop the load. 1st question how do I know the values of the rectifier, according to the schematic alls it says is something about -55v next to it. 2nd how can i figure what I need for a resistor. 3rd the extend Scott manual talks about needinga oscilliscope to set the bias is this necessary or is there a way around this. Thanks Nick Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted February 3, 2012 Share Posted February 3, 2012 here's a couple pics that may help. Notice the silicon rectifier is mounted right on top of the old selenium. Notice also there are no wires connected to the old selenium rectifier. it's just sitting there. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted February 3, 2012 Share Posted February 3, 2012 notice in this pic the RED wire coming off the NEGATIVE side of the silicon rectifier going to the little terminal strip and thence to the pair of resistors and on to the 4 caps and resistors. This is because the 4 section can cap was bad, couldn't get rid of the hum. I didn't know how to fix it so I sent it to a well-known Scott genius on this board who fixed it for me. I believe he used that pair of resistors to adjust the the negative 55V to the pre-amp tubes. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted February 3, 2012 Share Posted February 3, 2012 BTW, this particular Scott 222-C was one of the nicest sounding amps I've ever heard. It still had all the original Telefunken tubes in it and just just kicked butt all over the place hooked up to LaScalas or Khorns. I'm still sorry I ever sold it but money was tight and I had way too many amps. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted February 3, 2012 Share Posted February 3, 2012 here's the top side Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted February 3, 2012 Share Posted February 3, 2012 with wood: Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted February 3, 2012 Share Posted February 3, 2012 on my comp[uter with Google Chrome you can click on the pics to get a larger version. Quote Link to comment Share on other sites More sharing options...
The Dude Posted February 3, 2012 Author Share Posted February 3, 2012 thanks Tom nice pics, Why wasn't the old one removed, I guess I see how to do it. I just need to know the how to figure the specs such as what are the specs of the old rectifier, and how to figure what I need resistors. I hope to be able to get my 299 polished up like that it is very nice. Nick Quote Link to comment Share on other sites More sharing options...
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