Hello everyone here. I need help to understand why in the attached diagram there's a voltage of -21V between source pins of Q114 and Q115 and all three pins of BJT Q113, the same as the drivers collectors of Q111 and Q112.
I'm sure that the failure must be among those suspects but to my surprise, after desoldering all above mentioned transistors, Q111, Q112 and Q113 are correct! not showing problems when measured in diode mode with my tester Finest 503, showing the 0.7V that must be in the junctions.
About the Q114 and Q115 final Mos-Fet's, I'm not so sure about their state, I think they are open but I could be wrong because, maybe my humble tester may not supply enough voltage between gate an source to turn them on.
One thing I'm quite sure, all resistors involved are OK and both Q114 and Q115 kept cold after half an hour of turn the circuit on, while the other channel parts were warm to the touch.
I'm totally sure that with all 5ha information, someone with the needed skills will have all the necessary to explain what's going on and probably why. The replacements are on their way, I ordered all and therefore I'm going to gather all active devices form input to output to be ready to face any complication I could find... oh no! I can't attach the Diagram!!!
I'm sure that the failure must be among those suspects but to my surprise, after desoldering all above mentioned transistors, Q111, Q112 and Q113 are correct! not showing problems when measured in diode mode with my tester Finest 503, showing the 0.7V that must be in the junctions.
About the Q114 and Q115 final Mos-Fet's, I'm not so sure about their state, I think they are open but I could be wrong because, maybe my humble tester may not supply enough voltage between gate an source to turn them on.
One thing I'm quite sure, all resistors involved are OK and both Q114 and Q115 kept cold after half an hour of turn the circuit on, while the other channel parts were warm to the touch.
I'm totally sure that with all 5ha information, someone with the needed skills will have all the necessary to explain what's going on and probably why. The replacements are on their way, I ordered all and therefore I'm going to gather all active devices form input to output to be ready to face any complication I could find... oh no! I can't attach the Diagram!!!
Last edited: