Boss VB-2 switching and Q9 explanation please

[acobberson]

Hey there, hoping someone can point me in the right direction. I recently came across an original Boss VB-2 circuit board, minus the pots. I gutted a Metal Zone pedal and used a couple pots from it (correct values) and sourced the rotary switch to complete the pedal.
Anyway, it works and sounds great. Only trouble is I can't get the flip-flop to work. Haha, IT WON'T TURN OFF! I'm really hoping the BA634 isn't bad.

I checked voltages on the BA634 and it is getting 8.6V on pin 5 (the reset pin) and pin 1 drops to nearly 0V when the switch is pressed. It seems to me that it should be working, but this is the first time I have ever messed with one of these flip-flop circuits.

One other thing I noticed is that Q9 is missing and has been replaced with a jumper from collector to base. Not sure if that is factorry or not, but I am leaning to it NOT being a factory job because I have seen other gut shots that do have Q9 on board.
Can anyone explain to me the purpose of Q9 and whether it is necessary? It doesn't look like it is part of the flip-flop circuit, but could that be the reason the flip-flop isn't working correctly? I have some 2sc945 transistors on order, so I'll just drop one in when I get them to see if that makes a difference, but like I said, the effect is working other than the on/off flip-flop circuit.

Here is the schematic. Any insight into this wonderful pedal is greatly appreciated!
Let me know if gut shots or more voltage readings are necessary.

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/vb-2.jpg.html

[Rob Strand]

Well to me I think it is required.  Without it the modulation doesn't get through.  Q9 is just a buffer without it the modulation is disabled.  For now, you could put any old thing in there for Q9 and it will work, well maybe not a shoe.

[Rob Strand]

Haha, IT WON'T TURN OFF! I'm really hoping the BA634 isn't bad.

Huh.  That's not what I would expect with Q9 out.

Maybe someone has hard wired R55 or something?

I can't find a BA662 datasheet but  the way the circuit looks to me is is needs a positive current on the control pin (the pin that goes to R55, can't make out the pin number) to pass the modulation.

[acobberson]

Thanks for the input! I was incorrect when I said the jumper was put in collector to base. The jumper is actually wired to where Q9's emitter and base would be, so you are correct in assuming R55 was hardwired.

I am starting to think I wired the rotary switch incorrectly. Like I said, the effect is working, throbbing with the best of them even without a tranny in Q9 position, but since it is just a buffer the jumper in its place must be allowing the modulation through. So it shouldn't have any bearing on whether the flip-flop is working or not.

When I get home I can take some photos. Those always seem to help.

[Rob Strand]

So it shouldn't have any bearing on whether the flip-flop is working or not.

It doesn't affect the flip-flop itself,  however, the way the bypass works is the flip-flip
controls Q9 and if Q9 is hardwired whatever the flip-flop does gets ignored.
In bypass mode it just cuts the modulation.

So the hardwired R55 *is* the problem.

[acobberson]

Aha! That makes sense now. I was thinking more in terms of a "normal" Boss flip-flop. Great! Thanks for the help. I will toss a tranny in there and see what happens.