JamesMcB
New member
Hi all,
New user here. Just completed my first PedalPCB build - Cobalt Drive. I have built about a dozen effects from other vendors.
I am not getting any output when the effect is switched on. All is good when the pedal is in bypass.
Based on some other threads related to this board, I suspect that I have bad and/or bogus transistors. I am using MPF102's from Tayda, as J201s are made of unobtainum nowadays. Never had a problem with any parts from Tayda before, but maybe I've just been lucky so far. Being a new builder and electronics hack, I don't have enough knowledge yet to verify this myself. Any help from more seasoned minds would be greatly appreciated...
I have double checked all component values and re-flowed any connections that looked even slightly suspect. Still no joy.
Input voltage: 9.4V. Here are the voltage measurements I have at the moment:
Q1: D: 8.49V, S: 7.79V, G: 4.46V
Q2: D: 8.42V, S: 6.65V, G: 4.14V
Q3: D: 9.15V, S: 7.79V, G: 5.48V
Q4: D: 9.15V, S: 6.65V, G: 0V
IC1:
1: 0, 2: 4.56V, 3: 4.35V, 4: 0V, 5: 0V, 6: 4.56V, 7: 9.15V, 8: 0V
Q5: E: 9.15V, B: 8.49V, C: 5.74V
Q6: E: 9.15V, B: 8.42V, C: 9.13V
Q7: E: 3.30V, B: 3.76V, C: 9.15V
Any help would be greatly appreciated. I hate unfinished business.
If there is a better alternative to the J201s than the MPF102s, please let me know.
Thanks in advance.
New user here. Just completed my first PedalPCB build - Cobalt Drive. I have built about a dozen effects from other vendors.
I am not getting any output when the effect is switched on. All is good when the pedal is in bypass.
Based on some other threads related to this board, I suspect that I have bad and/or bogus transistors. I am using MPF102's from Tayda, as J201s are made of unobtainum nowadays. Never had a problem with any parts from Tayda before, but maybe I've just been lucky so far. Being a new builder and electronics hack, I don't have enough knowledge yet to verify this myself. Any help from more seasoned minds would be greatly appreciated...
I have double checked all component values and re-flowed any connections that looked even slightly suspect. Still no joy.
Input voltage: 9.4V. Here are the voltage measurements I have at the moment:
Q1: D: 8.49V, S: 7.79V, G: 4.46V
Q2: D: 8.42V, S: 6.65V, G: 4.14V
Q3: D: 9.15V, S: 7.79V, G: 5.48V
Q4: D: 9.15V, S: 6.65V, G: 0V
IC1:
1: 0, 2: 4.56V, 3: 4.35V, 4: 0V, 5: 0V, 6: 4.56V, 7: 9.15V, 8: 0V
Q5: E: 9.15V, B: 8.49V, C: 5.74V
Q6: E: 9.15V, B: 8.42V, C: 9.13V
Q7: E: 3.30V, B: 3.76V, C: 9.15V
Any help would be greatly appreciated. I hate unfinished business.
If there is a better alternative to the J201s than the MPF102s, please let me know.
Thanks in advance.