Gentleman,
I just acquired my second 700B and will get into the WOPL overhaul eventually. As I was listening to my new toy .. A pop and then a fizz and then the smoke came out....
I pulled it apart to see several burnt traces on the 14A driver board.... I decided to try a quick swap out the burnt 14A to the physically larger 14B board that was saved from my first 700B WOPL conversion ... I carefully compared both schematics and transplanted the board and it lives again! .... Sounds ok but I can't get any lower than 481mv bias.... both pots are full over to get that.... Am I missing something ? Has anyone made this swap and had the bias issue ? .. I did leave the bias transistors on the chassis as they tested ok.. Are they different numbers from board 14A to revision B ? And lastly, am I on the correct 10ohm resistor for proper measurement ?
Matt
I just acquired my second 700B and will get into the WOPL overhaul eventually. As I was listening to my new toy .. A pop and then a fizz and then the smoke came out....
I pulled it apart to see several burnt traces on the 14A driver board.... I decided to try a quick swap out the burnt 14A to the physically larger 14B board that was saved from my first 700B WOPL conversion ... I carefully compared both schematics and transplanted the board and it lives again! .... Sounds ok but I can't get any lower than 481mv bias.... both pots are full over to get that.... Am I missing something ? Has anyone made this swap and had the bias issue ? .. I did leave the bias transistors on the chassis as they tested ok.. Are they different numbers from board 14A to revision B ? And lastly, am I on the correct 10ohm resistor for proper measurement ?
Matt
Attachments
-
2.9 MB Views: 18
-
3.5 MB Views: 19
-
4 MB Views: 20
-
2.7 MB Views: 20