R40 gets hot, voltages a bit off
Posted: Sun Aug 20, 2017 4:07 pmHey everyone! So I've built two N72s that sound amazing, and working on my third.
This time, it seems that R40 is getting hot. I'm measuring correct voltages at Q1-Q3, but they're slightly off from Q4-Q6.
I did make a dumb mistake at one point, turning R39 CC clockwise rather than counter-clockwise, and saw a bit of smoke, though I killed the power immediately. Could this have fried anything important?
I've pulled out all the transistors and re-soldered, re-flowed everything in that area. Still getting these slightly off values, and can't touch R40 for more than a couple of seconds. Maybe this is all within a certain tolerance..
Q4
Collector: 5.6
Base: 0.88
Emitter: 0.3
Q5
Collector: 22.2
Base: 5.57
Emitter: 5.0
Q6
Collector: 22.2
Base: 4.97
Emitter: 4.39
This time, it seems that R40 is getting hot. I'm measuring correct voltages at Q1-Q3, but they're slightly off from Q4-Q6.
I did make a dumb mistake at one point, turning R39 CC clockwise rather than counter-clockwise, and saw a bit of smoke, though I killed the power immediately. Could this have fried anything important?
I've pulled out all the transistors and re-soldered, re-flowed everything in that area. Still getting these slightly off values, and can't touch R40 for more than a couple of seconds. Maybe this is all within a certain tolerance..
Q4
Collector: 5.6
Base: 0.88
Emitter: 0.3
Q5
Collector: 22.2
Base: 5.57
Emitter: 5.0
Q6
Collector: 22.2
Base: 4.97
Emitter: 4.39