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ts808 problem

Started by Culley713, June 18, 2008, 07:22:28 PM

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Culley713

Noob here.  This is my 3rd build, but more complicated than my first dod 250 and bobtavia.  Also I have basically no electrical knowledge background, I just pick things up quickly and am good at following directions.  So here goes...

1.Bypass works fine.  When switched on, the led turns on, but no sound at all.
2.ts808
3.http://www.freeinfosociety.com/electronics/schemview.php?id=1136
4.Didn't use one those pre made boards, just soldered it all together.  The only thing I changed was the 51pf cap to a 47pf just cause of availability (and I was told it wouldn't affect the sound).  I also put a switch between the .047uf cap and the 51k to pin 2 to switch out a different resistor and cap for more gain.  Added an extra diode for asymmetrical clipping.  Finally, I left out the diode and 100uf Cap from the power section because I've seen schematics without them.
5.^^^^
6.No
7.Voltage at the circuit board end of the red battery lead =9.65
Voltage at the circuit board end of the black battery lead =0.00

Q1         Q2
  c=9.65         c=9.65
  b=8.94         b=8.94
  e=8.94         e=8.94

IC1
  pin1=   4.91      pin5=4.90
  pin2=   5.20      pin6=4.91
  pin3=   4.82      pin7=4.91
  pin4=   0.00      pin8=9.64

D1=two diodes in series
   anode of 1st diode=4.91
   cathode of 2nd diode=5.20

D2
   anode=5.20
   cathode=4.90

Also, I used a 9v power supply even though I was supposed to use a 9v battery just because I never hooked up a battery clip.  If that is crucial, let me know and I'll solder one on.

Thanks.

jlullo

hey there!  you shouldn't be getting full voltage on Q1 or Q2.  Did you socket the transistors, or solder them directly?

Culley713

soldered them directly...did I fry them?

jlullo

#3
it's possible.. do you have any sockets or a heatsink?

Culley713

Got it!  Sorry, though, it was a dumb beginners mistake.  I didn't check the pinout on the transistors like it warns in the debugging page.  My bad, but thanks for pointing that out.

jlullo

you're welcome, i'm glad you figured it out!

Culley713

Ok, I actually built two of these pedals (one for me and one for my friend).  Mine worked fine after I fixed the transistors, and after fixing them on the second one, I got sound to come through, but there's a new problem.  When I strum, I get a mix of the TS sound with cracking and popping noise.

I have located the problem though, I just don't know how to fix it.  When I disconnect the power section I get the correct values, V+=9.6 and Vr=4.8, but when it is connected to the rest of the pedal, I get Vr=6.30.  Also, when I disconnect the power section again and test the voltages of where I connect the V+ and Vr to, I get some small volts that slowly decrease until they reach 0.  I guess this is just the Caps draining (?) but I didn't know if that was supposed to be there or not?