tomb
Member of the Trade: Beezar.com
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- Mar 1, 2006
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I agree with jdkJake ... plus - did you confirm that you indeed have the matched quad set of Toshiba JFETs - the 2SK170/2SJ74's? If not, they do NOT need to be reversed.
Please confirm whether you had the Toshiba JFETs or you just used the 2N5087/2N5088's for QB2 and QB3.
Also:
1. The "bridge" you mention is simply a scrape in the PCB's FRP. It won't affect anything and didn't touch a trace as best I can see.
2. Let me repeat jdkJake's emphasis on trimming the leads and cleaning things up. It sure looks like a couple of those leads are touching/shorting, especially around the CCS sections (RA8, RA9, and the two Wima capacitors and 2N5087's for each channel to the outside of the tubes)..
3. I'm concerned with the burn marks on the small transistor pads and the power MOSFET pads in the middle. It looks to me like those are not soldering burns and perhaps you fried a lot more when you had the buffer trimmers set to zero resistance. I'm thinking the entire bank of small transistors may need to be replaced.
Please confirm whether you had the Toshiba JFETs or you just used the 2N5087/2N5088's for QB2 and QB3.
Also:
1. The "bridge" you mention is simply a scrape in the PCB's FRP. It won't affect anything and didn't touch a trace as best I can see.
2. Let me repeat jdkJake's emphasis on trimming the leads and cleaning things up. It sure looks like a couple of those leads are touching/shorting, especially around the CCS sections (RA8, RA9, and the two Wima capacitors and 2N5087's for each channel to the outside of the tubes)..
3. I'm concerned with the burn marks on the small transistor pads and the power MOSFET pads in the middle. It looks to me like those are not soldering burns and perhaps you fried a lot more when you had the buffer trimmers set to zero resistance. I'm thinking the entire bank of small transistors may need to be replaced.