Optional Resistor

[Deep Blue]

I'm building a Green Ringer with info from General Guitar Gadgets, and it's not working. I didn't install the "optional" 4m7 Resistor, so those holes are empty on the PCB.  Should I put a jumper there or what?  I would install it, but Small Bear didn't give me one with my order.

What does it do anyways?

[petemoore]

simialar to but not octave.  Output was less than unity. I believe the 4.7m [if optional] would be be left open...nothing there. $.7 meg being so much closer to 'no connection' than zero resistance [what a wire jumper is very very close to.
 Mine worked best with a fuzz in front of it as I recall.
 I don't think that resistor is a 'disabling problem to the ckt.

[Deep Blue]

I know what the pedal does.  I was asking what the optional resistor did.

I tried it without the resistor, and it doesn't work.  I tried it with a resistor of random value and it doesn't work.  I'm guessing it doesn't work for some other reason.

Man, I'm getting pretty damn tired of making pedals that don't work.  This DIY business isn't working out too well, and I simply can't afford to just "keep at it."

[Rob Strand]

That resistor isn't going to make or break the effect.  You have a bug somewhere in there for sure.  Check,
- wiring (esp at the foot switch)
- you have got all you pnp's and npn's in the correct positions.
- your electro-caps and diodes the right way around.
- you could check the transistor pin outs but I suspect these match the board since it's a kit.

Beyond that, if you have a multimeter,
- check 9V is getting to the board
- measure the voltages on each transistor and report them here (JD sometimes has voltage check notes on his site, compare then against this if you can find them - otherwise just post the voltages)

[Deep Blue]

how do i measure trasistors?  I've got my voltage meter out.  What do I touch what to?

[Rob Strand]

What do I touch what to?

You put the meter - lead (black) onto the *ground on the PCB* and hold the there for all measurements.

To take measurements,  you just prod each pin of the transistors, with the meter + lead (red), and record the voltage.   Use the DC voltage range, 20VDC should do but for voltages below 2V you can get a more precise measurement with the 2VDC range.

Dont forget to measure the +9V on the PCB first, if there's no power you have found a problem - in this case the transistor measurements will all be zero and aren't of any use.

[Deep Blue]

They all register on the meter, but I have no idea how to read the meter.  Doesn't make any sense to me.

Screw it.  Anybody want to buy a non-functioned green ringer?  I'm not interested in spending hours and hours on top of the hours in spent to built it getting it to work.

[Deep Blue]

I got it working. Confusion was caused by a graphic in the FAQ here that says the sleeve generally goes to ground, when, in this project, it was to go to the negative battery thingy.  Next time I'll know to stick strictly to JD's guidelines.  Live and learn.

So what *does* the optional resistor do?  Should I buy one?

[bwanasonic]

I got it working. Confusion was caused by a graphic in the FAQ here that says the sleeve generally goes to ground, when, in this project, it was to go to the negative battery thingy.  Next time I'll know to stick strictly to JD's guidelines.  Live and learn.

So what *does* the optional resistor do?  Should I buy one?

Glad it turned out OK. The *optional* resistor is a "Pulldown" resistor to avoid popping when the effect is switched on. If you plan on making anymore effects (don't stop now!), buy a resistor assortment pack for about $8 from radio shack. It will have the 4M7 and enough other resistors for quite a few projects.  

Kerry M