BSIAB II... no sound [UPDATE: FIXED]

[robotboy]

Hi, I just finished a BSIAB II using Torchy's vero layout. I tested it last night, and... nothing. No sound at all. Not too surprised because there are a lot of parts. I just traced all the connections over lunch, and I couldn't find anything glaringly obvious that was wrong. I triple checked all my track cuts and jumpers, and they appear to be correct. Of course, something is wrong, or it would work. So, here's the breakdown.

Name of project: BSIAB II, from General Guitar Gadgets. Used vero layout from diypedals.com

Project Link:
http://www.generalguitargadgets.com/diagrams/bsiab_2_sc.gif

Admissions:
Followed the layout exactly. Ommited the LED connection. Substituted a 1uF aluminum electrolytic cap for the 1uF NP (C3A). Connected positive of 1uF to ground.

What does it do:
Nothing... no sound

Voltages (target voltages from GGG in parens):
Q1
G=0V (0V)
S=0.8V (0.95V)
D=5.77V (4.5V)

Q2
G=3.37V (3.8V)
S=5.78V (4.5V)
D=9.76V (8.0V)

Q3
G=0V (0.3V)
S=0.12V (0.75V)
D=4.87V (4.3V)

Q4
G=3.39V (3.8V)
S=4.85V (4.3V)
D=9.71V (8.0V)

Q5
G=-.02V (0.5V)
S=1.25V (0.9V)
D=4.42V (3.4V)

Resistance from input to output measures in a 1M.
Current consumption measures in at 2.4 milliamps.
Transistors are in the sockets and oriented correctly.

Any help would be awesome and appreciated!

p.s., it looks like Torchy's BSIAB II vero layout along with all his other layouts are no longer at diypedals.com, so I'm posting the layout I used here for reference.

[ninoman123]

Put the 1uf negative lead to ground. Negative lead always goes to where the less amount of voltage is. and in this case it would be ground. I dont know if this will solve it or if this is even a problem but that seemed wrong to me so...try it lol. Might help..if it doesnt get a non polarized.

[robotboy]

Put the 1uf negative lead to ground. Negative lead always goes to where the less amount of voltage is. and in this case it would be ground. I dont know if this will solve it or if this is even a problem but that seemed wrong to me so...try it lol. Might help..if it doesnt get a non polarized.

Thanks a lot for the help. Just a quick question. If the above is the case, why would the layout indicate positive to ground on C3A?

[ninoman123]

Yeah...not sure about that...I could be wrong...lol...seems weird that the + would be going to ground though. :?

[robotboy]

Put the 1uf negative lead to ground. Negative lead always goes to where the less amount of voltage is. and in this case it would be ground. I dont know if this will solve it or if this is even a problem but that seemed wrong to me so...try it lol. Might help..if it doesnt get a non polarized.

Well... I swung by ratshack and got a 1uF NP on the way home from work. Popped it in, and WOW! BSIAB II in full effect! Thanks for the help. I love this thing.

[ninoman123]

awesomeness. We still need to talk to JD about that cap though...did you try it the other way around?  Parts substitutions always screw up a build lol. Glad you got it to work though.  

[robotboy]

awesomeness. We still need to talk to JD about that cap though...did you try it the other way around?  Parts substitutions always screw up a build lol. Glad you got it to work though.  

I didn't try it the other way around because I was too eager to just it to work. I'd imagine that it would work the other way though since I isolated the problem to that component.

[MartyMart]

Thats wierd, C9's "ground" node is correct, follow it along the top trace
there is a track cut left of it so then it flows C8/ R8 which connects to ground !!
That looks correct to me ? :shock:

Marty.

[ninoman123]

Not C9. Look at C3A on GGGs layout.  GGG says you can use a polarized instead of a NP which is what robotboy used. I think the polarity of that cap should be the otherway around. The layout shows it as the + end going to ground...didnt seem right to me. :?:

[dosmun]

GGG says you can use a polarized instead of a NP which is what robotboy used. I think the polarity of that cap should be the otherway around. The layout shows it as the + end going to ground...didnt seem right to me.

That looks backwards to me.  I think I used a NP when I built mine so I didn't even notice the mistake. :?

[ninoman123]

:? Wheres JD when you need him  :?:

[Bagge]

It definitely is backwards. Negative from cap should go to ground. Positive to source of Q1.

[PaulH]

oops - repeated post  :oops: