Can't get this rebote 2.5 to work :(

[MikeH]

Started this one a couple days ago, can't make it happen though.  Checked all the joints, checked for connectivity, verified all parts, and everything looks cool.  Thanks in advance!

1.What does it do, not do, and sound like? Passes clean signal, but no delay, just a loud ticking, which is affected by the delay and level controls.  Anyone else have this happen?
2.Name of the circuit =rebote 2.5
3.Source of the circuit (URL of schematic or project) = http://www.tonepad.com/getFileInfo.asp?id=98
4.Any modifications to the circuit? No
5.Any parts substitutions? For once, no.
6.Positive ground to negative ground conversion? No
7.Turn your meter on, set it to the 10V or 20V scale. Remove the battery from the battery clip. Probe the battery terminals with the meter leads before putting it in the clip. What is the out of circuit battery voltage? => 9.61

Voltages:
IC1 (or U1) - TL072
P1 4.8
P2 4.8
P3 4.79
P4 0.0
P5 4.68
P6 4.8
P7 4.8
P8 9.60

IC2 (or U1)
P1 5.0
P2 2.5
P3 0.0
P4 0.0
P5 2.9
P6 2.49
P7 4.6
P8 4.6
P9 4.78
P10 4.34
P11 0.35
P12 4.77
P13 2.5
P14 0.23
P15 4.98
P16 1.2

I have no idea what these should look like.

IC3
P1 (left) 5.01
P2 (center) 0.0
P3 (right) 9.60

[MikeH]

Actually, I lied.  I used a 47pf cap instead of the 51pf and a 7pf cap instead of the 5pf.

[oskar]

Hi!
The higher the resistance to ground on pin 6 of the 2399 the longer the deley. Very longier deley = subaudio = ticking.
Could be the 500k delaypot isn't properly grounded which would give a supergroovy big resistance for pin 6.
Also the 1k in front of the pot could have been lying to you about it's proper value...

pt2399pdf  --->  http://www.princeton.com.tw/website/downloadprocess/downloadfile.asp?mydownload=pt2399_1.pdf

try shorting pin6 to ground with a 1k resistor...

[MikeH]

Cool.  Thanks oskar.  I did some searches for voltages and found a post that I think has the right voltages.  Does anyone know if pins 9-16 are all supposed to be at 2.5 volts?

[oskar]

Cool.  Thanks oskar.  I did some searches for voltages and found a post that I think has the right voltages.  Does anyone know if pins 9-16 are all supposed to be at 2.5 volts?

I think so... they are internally referenced to pin 2

[MikeH]

So my chip might also be toast?  It's possible, I got it in a trade; I don't know what was done with it before I got it.

[MikeH]

I tried shorting pin 6 to ground with a 1K resistor and no change.  I also tapped the signal off of pin 12 and just go ticking, no delay.  Can't find any bridges or anything that could be pulling my voltages off for pins 9-16.  Are these chips seriously easy to fry?  I've never fried any IC before, so I'm not really sure... and I did use a socket.

[MikeH]

Success.  Thanks for the help.  I ended up cleaning the flux off my pcb with a toothbrush and some acetone, which led me to a solder bridge (So tiny!  I couldn't believe it.  I thought it was a dog hair or carpet fiber or something) between what was essentially pin 14 and the 0.1uf cap on the left side of the board. 

[kawayanstrat]

Success.  Thanks for the help.  I ended up cleaning the flux off my pcb with a toothbrush and some acetone, which led me to a solder bridge (So tiny!  I couldn't believe it.  I thought it was a dog hair or carpet fiber or something) between what was essentially pin 14 and the 0.1uf cap on the left side of the board. 

We almost have the same problem,dude. Except mine does not tick. You did not do anything else to the circuit except clean the flux off the board? where did you find the solder bridge? I'm really starting to get tired of debugging my rebote 2.5 build. 

[MikeH]

Yeah, I say check your connectivity.  It was connecting pin 14 (trace under the 12k resistors) to the junction of the 0.1uf cap on th right side.  Tick tick tick!