Take pity on the noob!

[flavourful]

it's been over 8 hours since I started debugging this bloody thing (that being a ts808 clone w/ a few mods) and it's still not working.... not only that but I'm stepping out of the solid state amp world today, meaning I'm getting a tube amp, and I wanted this thing done when it got here. seems like that isn't going to happen at this point but I might have some time to finish before it gets here tommorow... um.. today. so here's the problem: I get a nasty crackle sound when the effect is on. I couldn't turn up the amp this late at night but I think I can hear a really weak signal coming through, but even if it exists it's not much. at the moment I think it's something wrong with the jfet switching and the true bypass. the bypass signal comes through clear as day and the little led from the millenium 2 bypass gets brighter when bypassed. the millenium circuit is using 1n914 diodes and 2N5457 for the FET.
       bypassed (brighter) Q_2N5457: G: 6.57
                                                                    S: 1.31
      effect 'on' (dimmer) Q_2N5457: G: 6.85
                                                                    S: 1.5                                     drain leads to ground on both
Isn't the light supposed to turn off when it's bypassed?? it actually doesn't turn off at all, it just gets really dim...

the real reason why this pedal isn't working is probably the two jfets in the circuit. To use the bypass the circuit has to always be 'on' and I'm not exactly sure how to acheive this. with my eight frusterating hours of doing stuff I mostly had the source and drain shorted and the power input. I had the first jfet in and left the source\drain shorted on the output one, then I put both back in. with them in I took a couple of readings...
     Q₁: G: 9.67 (this is connected to the power supply)
                           S: 9.31
                           D: 8.84

     Q₂: G:9.67
                           S:4.57
                           D:4.3

I don't know jack about JFETs but those seem like weird readings. anyways I need sleep since I have to work right away in the morning so here's any other information tht might be useful. most of the board gives readings around 4.5 volts. before when I shorted the source and drain on both it was about .65 on most components. the jfets are 2N3904... ummm.... thats it... so if any of you veterans out there can help me out I'd love to get this thing off the ground before my new toy arrives. thanks

[petemoore]

  and recommend alotting more time to the ETA, then triple it.
  the jfets are 2N3904
2n3904 is a Bipolar Transistor, not a Jfet.
  1rst things 1rst...I can't tell exactly what you're building, a schematic always helps.
  See the DEBUGGING thread.
  I get the idea you're building a TS with input/output buffers, and true bypass switching.
  I can't help debug Jfet Bypass switching, but, if your'e true bypassing the Circuit, Jfet switching isn't really necessary?
  Your Tube Amp will/should keep you entertained... , I'd just spend time with that for a while. Try to forget about the TS and Amp thing...look at the TS as a project that may take some time to figure out.
  Not sure but I think TS sound can be bought in good working order for quite inexpensive in a plastic enclosure, if TS sound MUST be heard soon, this would be the simpler way to attain it immediately.

[oldrocker]

OK I think that you're calling 3904 jfets and what you mean is PNP Bi- polar transistors.  Jfets are field-effect-transistors and are different from bi-polars.  The 3 pin layouts of a Jfet and Bi-polar arn't even close.
I  used Tonepads schematic to build mine which uses a true bypass.  True bypass is easier to get working right especially if you're not experienced since it's just a wire pretty much that jumps around your TS circuitry.  I always add my bypass circuit later after the project is up running and debugged especially if its a bypass other than true bypass so there is no confussion that the bypass isn't causing the problem.  For me I'd rather hear the results of the effect I'm building so I know it's working and could care less about bypassing until later when I've had the fun of mucking around with my new pedal.  I assume since you mentioned an LED that you do have some other bypass setup other than true bypass.  True bypass normally doesn't use an LED unless you incorperated yourself.  If I were you I'd find a way to disconnect your bypass setup and just work strickly with the TS circuit itself and debug that first than when you get that going dig into bypassing.  Sorry I'm not much help here but I think the people here can help you get it going faster if they know they're not dealing with a faulty bypass circuit.

[oldrocker]

I see that the generalguitargadget has a true bypass with an LED I see so if you used that you don't need a JFet at all.  Is this TS a store bought modded pedal or a DIY?  I'm not clear on this.

[flavourful]

I guess i was pretty vague on what I was doing. It's a tubescreamer layout from tonepad with the a few robert keely mods on top. the bypass is actually the only thing that works, it's a true bypass using the millenuim bypass circuit to incorperate an led. the scematics for that are on the geofex website under fx projects. I'd give the url but I'm on a dialup connection without a whole lot of time to spend. the scematics for the tonepad ts9 are at this little link:  (http://tonepad.com/getFileInfo.asp?id=81)      it's got to be something wrong with the board. does anyone have the voltages for the pins on the IC or any other places for use for troubleshooting?. I already checked and rechecked the power and grounds and component placement. everywhere on the board was getting power, all wires have been triple checked. I can't think of anything else to check, it just makes this sickly crackleing noise and it might have a bit of teh signal coming through, though it's so quiet I couldn't hear if it was distorted or not. I think its got to be something wrong with the IC voltages or what i'm doing to the transistors. to make it so it's always on I'd have to jumper the signal path and leave the connection to the power empty, right? though at this point I think I'm going to put it away for a few days and take a fresh look if I can't get it going in the little time i have befre my amp gets here. I think that'll keep my busy for a while anyways     (that doesn't mean I don't still need help!)

[slacker]

The transistors in the tonepad layout, which are 2n3904s not jfets, are not anything to do with the switching they're just input and output buffers you don't need to do anything with them, the pedal is already "always on". I think you're getting confused because the real Ibanez tube screamer does have jfets that need removing to make it always on.
As for voltages the opamp should be roughly like this
1 4.5
2 4.5
3 4.5
4 0
5 4.5
6 4.5
7 4.5
8 9
The numbering goes down the left hand side and then up the right hand side when viewed from above. The transistors should be
collector 9 volts
base 4.5 volts
emitter 4.5 volts or a bit lower.
Basically on the tonepad layout the green bits are ground 0volts, the red bits are 9 volts and the blue bits are either 4.5 volts or have no DC voltage.
Hope that helps.

[oldrocker]

Try making up an audio probe and follow the signal and see if you can get somewhere with it.  That's how I got mine working when I first fired it up.  I haven't seen that you probed it yet.  This I know from experience can make all the difference in getting it working.