Folks,
Well, I came across this site by accident. I was looking for some guidance on a circuit I am trying to repair and found a similar issue here on this site. Actually, just a similar circuit. Hopefully I can get some good info here and relearn stuff I probably forgot from 20 years ago.
What I have is a guitar effects device that has a Momentary switch that "should" activate a latching circuit, turning on the distortion. Press the switch a second time and it should turn off the distortion. Situation is when the switch is pressed, nothing changes. But, I discovered that when I put a test lead on either the point of R40 or R43 where it meets with pin 2 of eihter Q16 or Q16 respectively, then the LED comes on and the circuit is active. However, it stays active ONLY if the switch is kept in a closed position.
Am I looking at a failed device in Q6 or Q4? And why doesn't the switch work to activate or deactivate the latching circuit.
Or, worse case, I am totally wrong in my thoughts on the latching circuit and there is something real obvious that I am missing.
Any guidance would be greatly appreciated.
Regards,
Andy S.
Schematic is at:
http://www.schematicheaven.com/effects/boss_bd2_bluesdriver.pdf
Well, I came across this site by accident. I was looking for some guidance on a circuit I am trying to repair and found a similar issue here on this site. Actually, just a similar circuit. Hopefully I can get some good info here and relearn stuff I probably forgot from 20 years ago.
What I have is a guitar effects device that has a Momentary switch that "should" activate a latching circuit, turning on the distortion. Press the switch a second time and it should turn off the distortion. Situation is when the switch is pressed, nothing changes. But, I discovered that when I put a test lead on either the point of R40 or R43 where it meets with pin 2 of eihter Q16 or Q16 respectively, then the LED comes on and the circuit is active. However, it stays active ONLY if the switch is kept in a closed position.
Am I looking at a failed device in Q6 or Q4? And why doesn't the switch work to activate or deactivate the latching circuit.
Or, worse case, I am totally wrong in my thoughts on the latching circuit and there is something real obvious that I am missing.
Any guidance would be greatly appreciated.
Regards,
Andy S.
Schematic is at:
http://www.schematicheaven.com/effects/boss_bd2_bluesdriver.pdf