Intermittent TS9 switching BUT switch is OK

[Bassbob]

I have a TS9 that turns on/off when it wants too. I took out the momentary switch to check it in an other circuit and its is functionning. So what could be the problem if its not the switch?

[antonis]

Power On-Off or signal On-Off..??

[anotherjim]

Intermittent DC power connection? The switch controls a flip-flop which is a 1bit volatile memory. If the power drops out momentarily, the flip-flop forgets you wanted the FX on. You may just have a 2.1mm DC plug that isn't a good fit in the socket or a faulty DC cable plug or socket.

[ElectricDruid]

Intermittent DC power connection? The switch controls a flip-flop which is a 1bit volatile memory. If the power drops out momentarily, the flip-flop forgets you wanted the FX on. You may just have a 2.1mm DC plug that isn't a good fit in the socket or a faulty DC cable plug or socket.

I'd say this is quite likely. DC sockets that are soldered to the PCB often finish up cracking the solder joints (and sometimes the PCB tracks too) because the plug gets wobbled and that force is transferred to the board.

[iainpunk]

i bet its a bad cap in the flip flop circuit. have repaired 2 ''sound tank'' series Ibanez pedals which had similar problems.

cheers

EDIT: after reading Rob's comment, my memory got jostled and it was not a bad cap but i did replace it with a bigger one. sorry for the msitake, it was over 4 years ago

[Rob Strand]

For fact the switch seems OK but it is intermittent in use is a strong sign the switch is old and starting to bounce.  The flip-flip on the footswitch circuit doesn't handle switch bounce very well.

On footswitch circuit there is a resistor in series with the footswitch then a cap to ground, usually 1nF. Increase the cap value to 47nF,  you might get away with 10nF.  As a test you can tack solder the cap across the existing 1nF.

FWIW:  there's no real reason to use a 10nF over a 47nF, the 47nF will fend off more aggressive bouncing.

[intripped]

It could be a dirty/rusted DC socket

[Rob Strand]

It could be a dirty/rusted DC socket

In reality it *could* be any of the above.  Even a cracked solder joint on a part somewhere on the PCB.
That's the hassle with faults (and circuit debugging) you just have to work through the options.

[intripped]

...I just gave another option.
Probably I should have said "it could also be", but for sure I didn't mean "it could only be"

[Rob Strand]

...I just gave another option.
Probably I should have said "it could also be", but for sure I didn't mean "it could only be"

That's how i read it too - I wasn't criticizing what you said at all.

I was just trying to make things clear for the OP.

Like most of these threads different members throw up the various options and someone might
*guess* the final fault but in many cases it was just a best guess.   There might be a few faults where
someone knows some secret info.

[ThermionicScott]

If the battery clip still works, that'd be an easy way to rule out the DC jack or plug. 

[WoundUp]

Nothing to really add. I've got an opposite issue. One of my distortion pedals randomly turns on, it seems. I think it might be the power supply somehow. I swear it did this once before, as well as randomly turning off, when it wasn't getting enough current.

I don't guess that could be an issue here?

[ElectricDruid]

If the battery clip still works, that'd be an easy way to rule out the DC jack or plug. 

Not necessarily, if the battery is switched through a NC contact on the DC jack. Bad jack or cracked track caused by the jack would both affect the battery too in that case.

I think we need BassBob to come back and tell us some more.

[iainpunk]

wonder if its bass bob from a local Arnhem band that recently broke up... doubt it tho.
my band now employs one of the guitarists.

cheers

[Bassbob]

First, let me thank you all for your helpful input.

Just to make things clearer about the issue on this repair:
When my friend brought the pedal to me the first time it had a DC jack's cracked solder joint that I fixed easily.
I checked it again this time and it's OK.
This time the footswith works randomly. It can work properly for, I didn't count, but lets say 20 stomps in a row then it goes bad, stay on or turns off for one or two stomps. But there is no real constancy.

So I tried Rob Strand suggestion

For fact the switch seems OK but it is intermittent in use is a strong sign the switch is old and starting to bounce.  The flip-flip on the footswitch circuit doesn't handle switch bounce very well.

On footswitch circuit there is a resistor in series with the footswitch then a cap to ground, usually 1nF. Increase the cap value to 47nF,  you might get away with 10nF.  As a test you can tack solder the cap across the existing 1nF.

FWIW:  there's no real reason to use a 10nF over a 47nF, the 47nF will fend off more aggressive bouncing.

The pedal now seems to work correctly. Again thank you all guys!

P.S. No, I'm not bass bob from Arnhem, I'm from Montreal and play bass in Beats On Noise

[ElectricDruid]

Nice work getting it going! 

And thanks for the update!