Hi guys, I'm stumped.
First off, here is the schematic that is closest to what I have here:
https://www.pcbway.com/project/shareproject/ZVEX_Super_Duper_2_in_1.html
One transistor is just not biasing properly.
Side 1 is the one I am having issues with. It is sputtering like it is starved for voltage - which as you'll see, it is. I have pulled all the resistors up near it and they have all measured fine. I thought maybe the transistor had failed, so I replaced it, and the voltages are the same.
Here are the voltages I am getting. They are taken with the gain controls (C5K) down:
Side 1
D - 4.8v
G - 1.64v
S - 4.1v
Side 2
D - 7.2v
G - 2.69v
S - 1.83v
I have 9 volts at the front side of both 5k1 resistors, but then the voltage drop across the 5k1 resistors coming from the power rail is:
Side 1 - 4.33v
Side 2 - 1.93v
I have tested the diodes and they seem to have a reasonable voltage drop across all of them.
It is just not making any sense to me. What else could be causing this voltage discrepancy.
First off, here is the schematic that is closest to what I have here:
https://www.pcbway.com/project/shareproject/ZVEX_Super_Duper_2_in_1.html
One transistor is just not biasing properly.
Side 1 is the one I am having issues with. It is sputtering like it is starved for voltage - which as you'll see, it is. I have pulled all the resistors up near it and they have all measured fine. I thought maybe the transistor had failed, so I replaced it, and the voltages are the same.
Here are the voltages I am getting. They are taken with the gain controls (C5K) down:
Side 1
D - 4.8v
G - 1.64v
S - 4.1v
Side 2
D - 7.2v
G - 2.69v
S - 1.83v
I have 9 volts at the front side of both 5k1 resistors, but then the voltage drop across the 5k1 resistors coming from the power rail is:
Side 1 - 4.33v
Side 2 - 1.93v
I have tested the diodes and they seem to have a reasonable voltage drop across all of them.
It is just not making any sense to me. What else could be causing this voltage discrepancy.