Paragon OD No signal

[cai]

Hey all, just finished building the paragon overdrive. I have an issue where there is no signal. When the effects are enabled, the led stays off and the signal cuts off. The bypass works so I know the issue isn't with the input/output jacks. Anyone have any experience with this circuit and can advise my troubleshooting?

Here are the DC voltages for the ICs

IC1 (JRC4580D)

Pin 1: 3.5v
Pin 2: 1.25v
Pin 3: 1.2v
Pin 4: 0v
Pin 5: 1.2v
Pin 6: 1.25v
Pin 7: 1.25v
Pin 8: 16.8v

IC2 (JRC4580D)

Pin 1: 1.3v
Pin 2: 1.3v
Pin 3: 1.2v
Pin 4: 0v
Pin 5: 1.1v
Pin 6: 1.1v
Pin 7: 1.15v
Pin 8: 16.7v

IC3 (TC1044SCPA)

Pin 1: 9.1v
Pin 2: 5.7v
Pin 3: 0v
Pin 4: -2.9v
Pin 5: -2.9v
Pin 6: 4.4v
Pin 7: 5.65v
Pin 8: 9.2v

I have a feeling something is wrong with the charge pump (IC3) but I've no idea where to start.

 

[cai]

The fact that the leds wont turn on surely means its a power issue right? Unless of course the leds are faulty

 

[Nic]

Pictures ? The bypass could also work with both jacks wired wrong.

 

[cai]

Pictures ? The bypass could also work with both jacks wired wrong.

Will upload now, Im almost certain that the jacks are wired correctly, I've looked them over and even tested continuity to be extra sure

 

[cai]

Are there any specific pics you want?
The extra toggle switches are for ckaudioeffects high/low gain mod

 

[PunchySunshine]

View attachment 84711
Are there any specific pics you want?
The extra toggle switches are for ckaudioeffects high/low gain mod

Is your 1044 installed upside down?
It's correct. Sorry.

 

[andrewsrea]

From your pin voltages, it appears that your Vref circuit has the wrong resistors in the voltage divider (R12 & R13). I am going to guess that you installed a 4k7 resistor for R13 instead of a 47K.

All of your RC4558 pins, except #4 (0 volts) and #8 (near 18V), should be around half of Vcc (9v).

The reading of 16.8v indicates the charge pump is operating, but is being pulled down by the Vref. Further validation that is where the problem is.

 

[cai]

So would the charge pump not working correctly, would that cause the lack of signal with the circuit engaged?

I'm really new to electronics beyond wiring guitars. So when it comes to troubleshooting and diagnosing where the problem is I don't really have a clue. I'll check those resistors now and see if that solves it. Hopefully I can get it working,

Will report back

 

[Nostradoomus]

Most of the solder joints I can see look pretty cold, what's the bottom look like?

 

[Nostradoomus]

Also is the 10u cap to the left of the charge pump oriented properly? (there's been revisions where it was the other way around, if you followed the silkscreen on the board you're good)

 

[cai]

Most of the solder joints I can see look pretty cold, what's the bottom look like?

I'll reflow the board now and see if that helps

 

[cai]

Also is the 10u cap to the left of the charge pump oriented properly?

Yeah I've checked that, it's oriented as show on the silkscreen

 

[cai]

Most of the solder joints I can see look pretty cold, what's the bottom look like?

I've reflowed it, it still isn't working. I'm unsure on how to proceed. Theres clearly something wrong power wise, don't know if thats causing the lack of signal or if its a separate problem.

 

[Nostradoomus]

I'd like to see more pics

 

[temol]

Can you measure the voltage at the marked point? The charge pump appears to be working correctly.

 

[cai]

Can you measure the voltage at the marked point? The charge pump appears to be working correctly.

View attachment 84782

When I first put the multimeter probes on the resistor leg it read about 8v before dropping and hovering around 1v/1.5v

 

[cai]

I'd like to see more pics

Anything in particular? Just the other side of the board.