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I just finished putting this together and I get bypass but no sound. I can barely hear a buzz when I hit the strings but controls do nothing to affect the sound
The 9v pad that you are currently connected to looks burnt out.
You can test to see if you are getting 9v at the R27 pad right next to it (see photo). Also check that you are getting voltage to Pin 1 of the IC Chips.
I would try connecting it to the other 9v pad if that is the issue.
Barry, I am getting power to 27, 9V… at pin 1 of the IC’s 1st – .06v, IC2 – .06v, IC3 .73v, IC4 .02v
I did change the power to the other hole, I am picking up am radio at this point however still no control
Thoughts?
Tom
I am not sure what is going on there but I would do a complete reflow and make sure all grounds are good.
R28 must be your problem it’s difficult to see but it looks like a 10K ohm – brown black black red brown or a 1K ohm – brown black black brown brown and not a 10 ohm – brown black black gold brown
You should have around 8.7v ish to pin 8 of all your ICs and around 4.5v on IC1B and IC2B pin 7
I changed R28 to 10R and the IC voltages are as follows
IC1 Pin 8 – 6.8vdc, Pin 7 – .7vdc, Pin 1- .5vdc
IC2 Pin 8 – 8.8vdc, Pin 7 – .7vdc, Pin 1 – .5vdc
IC3 Pin 8 – 6.8vdc, Pin 7 – 4.5vdc, Pin 1 – 0vdc
IC4 Pin 8 – 6.8vdc, Pin 7 – 5.3vdc, Pin 1 – 0vdc
The four LED’s on the board glow when I turn the volume up all the way (no strumming). I can hear the other pots affect change in tone when rotated however nothing but a faint spitting sound when strumming the guitar.I still get bypass sound.
There may be nothing to do but just start over with a new board. Working on this one more will result in more issues, however I want to learn from my mistakes so I don’t keep making the same ones on projects going forward.
As always, thank you for the great product and support.
Tom
Post voltages for every pin of all ICs
It seems strange that you’re getting VB on output pin 7 of IC3 and 4 but not pin 7 of IC2B where VB originates, so all pin voltages might highlight something
Your pin 8 readings should be more or less the same as you can see in the power section bottom left of the schematic, voltage to all pin 8s comes after C21
It’s just a process of elimination from your voltage readings it does appear that your problem lies in the power section I would double-check all component values and orientation we know that you’re getting 9v in you’ll drop around 0.4v through D9 so your problem is likely in the power section or something it connects to
Make sure all of your op amps are securely clicked into their sockets, where did you get them from I’ve seen a few posts of late with dodgy Tayda TL072s
You could also remove the op amps from their sockets and check voltages on the empty sockets to see if that makes a difference
Op amps as you know are active devices if there’s a solder bridge somewhere it may only be connected with them in socket
So if you check the voltage on the empty socket and get good voltages either the op amps faulty or there’s a bridge or some other problem causing it to malfunction
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