"FIXED": Boss DS1 Distortion knob problem

[sonofmickel]

Hi all, first post

Just got a Boss DS1 from a neighbor, looks brand new(old school, big resistors caps etc...).

The pedal "works", light comes on, bypass works fine, but very strange behavior on the Distortion knob, full counter-clockwise there is no distortion, turn up a little and the distortion comes on fast up to half way on the knob, then the distortion cuts off(guitar sounds clean again) and volume drops off to zero by full clockwise.

Bad IC chip?
Chip is NJM3404AL



OpAmp voltages
Pin 1-4.18
Pin 2-4.19
Pin 3-4.09
Pin 4-0
Pin 5-4.18
Pin 6-4.06 Dist knob counter clockwise, 4.10 Dist noon, 1 o'clock 3.4, 2 o'clock 2,4, 4 o'clock 1.18, 5 o'clock .52
Pin 7-4.04 Dist knob counter clockwise, 7.68 Dist noon, 8.14 Dist clockwise
Pin 8-8.13 Dist knob counter clockwise, 8.32 Dist noon, 8.34 Dist clockwise

[ElectricDruid]

I'd guess that one of the wires or joints to the distortion pot has gone bad. Turning the pot shouldn't really alter the pin 6 voltage, so that suggests that there's no feedback connection. I'm guessing it's grounded at one end, wiper to pin 6, and open at the end that should be connected to pin 7. With the power off, you could do a continuity check to see if that was the case.

Good luck!

[sonofmickel]

Whooot!
You were right!
Looks like too much glue on the ribbon cable, both ends(board and pot).
Solder sucker took care of the old solder. Had to clean the pads really well of burnt glue and flux.
The DS1 works like a gritty lazer beam to the ears now, just like I remember...I'll be smoothing that out a little bit with some cap mods.

Thanks ElectricDruid

[ElectricDruid]

Excellent, glad to hear you got it going.

Enjoy!

[antonis]

 $#&%$ *&^(% ribbon cables..!!