Maleficent Mids - no output

[waaaaaark]

My Mal Mids passes dry signal, but I get nothing when I engage the switch. LED works when it’s inserted. When I work the knobs I can sometimes hear a little bit of frequency sweeping, but no guitar. Foot switch was tested and appears working properly, the IC is receiving power (not sure what the numbers are supposed to be), reflowed all joints at least once. What am I missing?

 

[darwin999]

First re-check all your components, make sure they are the right values + confirm polarities where they exist.
Your 2 film caps look fine. But when I tried checking your resistors the colors seemed off/skewed in the pics, so it was hard for me to check them. E.g., R2 (470K) looks like yellow-blue-black-grey which can't be right.

By any chance is there something connecting the right sides of R3 and R7 on the top of the PCB? Maybe it's just a reflection, hard to see. I also can't see the lettering on the TL072 and NE5532, although their orientation looks good.

 

[jwin615]

First step in dry signal only: did you in the out hole?

 

[Nostradoomus]

Is that a piece of electrical tape behind the dual gang pot? Use something thicker, a lot of your clipped leads look pretty pokey and they'll go right thru tape.

 

[waaaaaark]

Is that a piece of electrical tape behind the dual gang pot? Use something thicker, a lot of your clipped leads look pretty pokey and they'll go right thru tape.

I'll try that. I've pulled the pot completely away from those leads while play testing and it didn't solve the problem.

 

[waaaaaark]

First re-check all your components, make sure they are the right values + confirm polarities where they exist.
Your 2 film caps look fine. But when I tried checking your resistors the colors seemed off/skewed in the pics, so it was hard for me to check them. E.g., R2 (470K) looks like yellow-blue-black-grey which can't be right.

By any chance is there something connecting the right sides of R3 and R7 on the top of the PCB? Maybe it's just a reflection, hard to see. I also can't see the lettering on the TL072 and NE5532, although their orientation looks good.

I've started going through the components now. R2 seems to be correct, reading at around 470k. Some of these other ones are a little strange, like R6 is reading 12.8k rather than 22k and R14 is reading 4k rather than 6k8. Seems like these are both outside of expected tolerance?

On R3 and R7, thats just the pcb trace with some reflection. No actual connection

 

[waaaaaark]

First step in dry signal only: did you in the out hole?

Hopefully this is right?

 

[Nostradoomus]

Measuring resistors in circuit will give you readings all over the place. Visual inspection of the printed values is more critical, that's what we mean.

 

[jwin615]

Hopefully this is right?

Was a half-joke
Make sure you plugged into the in, not out.Easy to do when it's late and the circuit is upside down.

 

[comradehoser]

Was a half-joke to
Make sure you plugged into the in, not out.Easy to do when it's late and the circuit is upside down.

Yep, can vouch for this being a common issue.

Also, I'm unfamiliar with your type of 9v jack. Check to see if the ground is connected to ground and the live lug to "+". Recently was stumped by a non functioning pedal until I realized that I had switched the wires.

 

[Diynot]

If all your values check out, try checking continuity on the footswitch to make sure no solder got under the board and is making an unwanted connection. When the switch is set to circuit on, you should only have continuity on pins 1/2, 4/5, and 7/8. Pay special attention for any connections between 1/2/7/8 and 4/5 since 4/5 connect to ground

 

[PJS]

What voltage readings are you getting on your ICs?

Also, I can see you have used pot dust covers on the single gang pots. If you have spares I have successfully cut one down to go on a dual gang pot before.