Octanaut suddenly just not

DGWVI

DGWVI

Well-known member
So, this was working fine on the test rig (meaning no bypass footswitch or board), and now I get no effect signal after boxing it up. I do still get crackle if I adjust the bias of any of the FETs, and the clean signal is fine

MOSFET Voltages (bias pots set to 50%) D-G-S
  • Q1 - 3.3 - 1.03 - 2.71
  • Q4 - 3.34 - 1.02 - 2.68
  • Q6 - 3.44 - 2.26 - 2.82
  • Q3 - 3.36 - 1.04 - 2.74
BJT Voltages E-B-C
  • Q5 - 3.78 - 4.44 - 5.35
  • Q2 - 3.78 - 4.43 - 5.37

Only parts subbed are the 5.1k and 2ks- I used 5.6k and 2.2k respectively. And I used BAT46 for the diode rings. Bias Pots 3 and 6 are panel mount, obviously.

received_546816590643646.jpeg received_956933871936592.jpeg received_1383904459092773.jpeg orca-image--1257059834.jpeg
 
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Did you re tested it out of the box ? You will then know if something is touching inside the box or if it is a problem with the switch wiring.
 
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Nic said:
Did you re tested it out of the box ? You will then know if something is touching inside the box or if it is a problem with the switch wiring.
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Yep, tested outside the box. Worked fine. Got it wired up and boxes it, and nothing. And, I get nothing outside the enclosure either. So, I'm guessing a wiring fault that I can't seem to see
 
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hamerfan said:
I guess a weak solder joint broke while you were boxing. Reflow all connection from the board and to the switches and jacks.
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Cleaned the board and reflowed everything.

In probing, I get audio up to the Gate of Q6, then nothing downstream, except I can hear the bias pots being moved :unsure: .
I've replaced R19, 20, 21, D5, and Q6.
I don't see any damaged traces
 
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Have you checked pot six? I know you put them off board but they are part of q6 to ground. Additionally you might want to check that area for continuity. Even though you cannot see a damaged trace if you don’t have continuity for whatever reason it will present itself that way.
 
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carlinb17 said:
Have you checked pot six? I know you put them off board but they are part of q6 to ground. Additionally you might want to check that area for continuity. Even though you cannot see a damaged trace if you don’t have continuity for whatever reason it will present itself that way.
Click to expand...
Yep, pot six checks out. I also swapped it for a trimmer, and still got nothing.
Continuity appears to be good everywhere in that portion. I'll do another deep dive when I get back home
 
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