Earth_Coven_Audio
New member
Hi Everyone. My son is working on his first Recap on a 1973 Sunn Studio Lead Combo amp.
The Blue Wire from the OT Secondary (point 12) came loose while he was working, when he turned on the amp he noticed the loose wire but not before R137 started bubbling and smoking a bit. He's now getting anywhere from 18 - 48 volts dc everywhere between the OT, output transistors (Q1,Q2) and to the Speaker jack. He doesn't really want my help which I respect but I'm thinking its either the lack of Secondary caused the resistor to meltdown (its not visibly burnt) and R137 itself needs to be replaced to redivide the voltage correctly or both Q1, Q2, and R137 all need to be replaced due to the excess voltage running through them. Any ideas and any suggestions for how to lead him to the answer?
The Blue Wire from the OT Secondary (point 12) came loose while he was working, when he turned on the amp he noticed the loose wire but not before R137 started bubbling and smoking a bit. He's now getting anywhere from 18 - 48 volts dc everywhere between the OT, output transistors (Q1,Q2) and to the Speaker jack. He doesn't really want my help which I respect but I'm thinking its either the lack of Secondary caused the resistor to meltdown (its not visibly burnt) and R137 itself needs to be replaced to redivide the voltage correctly or both Q1, Q2, and R137 all need to be replaced due to the excess voltage running through them. Any ideas and any suggestions for how to lead him to the answer?
