Tremulus lune Debug.

[funkbass187]

It's my first time having to go this far in finding out what's wrong with the circuit. hopefully someone can point me in the right direction for fixing this. no sound is going to the amp when the effect is engaged.

thanks for the help.

1.What does it do, not do, and sound like?: no sound is coming to the output
2.Name of the circuit = tremulus lune
3.Source of the circuit (URL of schematic or project) = http://www.indyguitarist.com/torchy/Tremolo/Tremulus%20Lune/  (the layout i used isn't up there anymore, what's posted is what seems to be the earlier stages of the layout development. if i recall correctly the circuit used was the old 4ms version and not the more recent one.
4.Any modifications to the circuit? No
5.Any parts substitutions? no
6.Positive ground to negative ground conversion? no
7.battery voltage? = 9.05V

Voltage at the circuit board end of the red battery lead =
Voltage at the circuit board end of the black battery lead =

IC1: JRC4885
1: waivers between 4 and 6.5v
2: waivers between 4 and 6.5v
3: waivers between 4 and 6.5v
4: 0
5: 0
6: waivers between 4 and 6.5v
7: waivers between 4 and 8.24v
8: 9.03v

IC2 TL072
1: 8.42v
2: 8.36v
3: 8.32v
4: 0
5: 0
6: 8.42v
7: 8.42v
8: 9.01v

[caress]

it shouldn't matter whether the LFO portion is working or not to get sound, so you should be looking in the buffer (TL071) section.  i'm pretty sure the voltages for the 741 should be a good deal lower than that.  check for solder bridges, etc...also, i think there should be some voltage across pin 5 on the 741.  check out around there..

iirc, the voltages for the LFO look good.  is your LED blinking?

[Laus]

just built myself one: http://www.newtone-online.nl/forum/index.php/topic,911.0.html
Have to finish the perflayout though.

1. Does your led blink?
2. Could some IC's be flipped around?
3. Do you have sound after the first buffer before the LDR? When you tear out the LDR?

Would like to know that first. Then we can better check where the trouble might ben.

[funkbass187]

i ripped off the electrical tape i used to enclose the led/ldr and the led is blinking as it should. it just dawned upon me to use my dmm to check for shorts rather than looking and seeing if anything is visible. i'll double check the buffer as mentioned. 

Thanks for the help so far.

[jlullo]

funk bass,
whenever i've had problems with the output and had (almost) full 9v at the IC where i shouldn't, it's been cold solders around that area.  if anything looks "blobby" to you, i'd touch it up.  in fact, that's been my biggest problem lately.... damn rat shack soldering irons!

[(doug harrison)]

It's hard to tell what's what from the layout you link to, but your voltages say something. Pin 5 of the TL072 should have about 4.5V. There should be a 100k/100K divider with 10 uF from pin 5 to ground.

4558, also pin 5 should have a reading around 4.5V, but it will vary with spacing.

[(doug harrison)]

On the TL072, pin 3 should also be about 4.5V. Somewhere there should be a jumper between pins 3 and 5.

On the 4558, check the spacing pot connections.

[funkbass187]

i finally figured out where exactly i went wrong, the capacitor and resistor on the column all the way to the right were shifted up a row. easy fix...  Thanks for all the help.