cupcake problem

[midwayfair]

wow! did i screw up! in these readings, i was looking at the bottom of the pcb. i put Q1 and Q2 backward! now that i have the pin id for the ic, i discovered #1 pin on the ic reads 9.29v. and after retesting the ic, it's actually reading -.1mv on pins 5 and 6. pins 2 and 3 read 8.79v, pin 6 is .492v, pin 7 is .398v and pin8 is 8.58v. now i get  the feeling this is not a short circuit issue...
by the way, in this photo the readings are corrected.

After fixing Q1 and Q2 and rebiasing, do you still have problems?

Your voltages are high on the op-amp's 1-3 pins, though. Those should be about
1: 4.5v
2: 4.5v
3: ~3.8v

You may need to pull the op amp, unfortunately, if you've exhausted all possible problems in the power section and isolated the audio section. I know it's not fun to desolder a chip, though.

[TreeSlayer]

wow! did i screw up! in these readings, i was looking at the bottom of the pcb. i put Q1 and Q2 backward! now that i have the pin id for the ic, i discovered #1 pin on the ic reads 9.29v. and after retesting the ic, it's actually reading -.1mv on pins 5 and 6. pins 2 and 3 read 8.79v, pin 6 is .492v, pin 7 is .398v and pin8 is 8.58v. now i get  the feeling this is not a short circuit issue...
by the way, in this photo the readings are corrected.

After fixing Q1 and Q2 and rebiasing, do you still have problems?

Your voltages are high on the op-amp's 1-3 pins, though. Those should be about
1: 4.5v
2: 4.5v
3: ~3.8v

You may need to pull the op amp, unfortunately, if you've exhausted all possible problems in the power section and isolated the audio section. I know it's not fun to desolder a chip, though.

actually Q1 and Q2 were installed proper, i just id'ed them wrong in the first drawing. with Q1 and Q2 in the origial picture made it look like i was looking at the top of the board when i wrote down the readings. i think that's why pin 1 on the ic looked like it had low voltage.

what is rebiasing, and how do i do it?

[midwayfair]

what is rebiasing

Just turning the bias trimpot.

...

We have established that you've fiddled with the bias pot and it doesn't work properly, right?

[TreeSlayer]

what is rebiasing

Just turning the bias trimpot.

...

We have established that you've fiddled with the bias pot and it doesn't work properly, right?

now that's strange... i answered my own question when your post popped up. adjusting the trimpot dosen't change anything...

[wgc]

Yep, counter intuitive to add solder when you want to unsolder but it really helps get heat transfer going.

You're close man, I can feel it

Merry Xmas! I'm out until after

[TreeSlayer]

Yep, counter intuitive to add solder when you want to unsolder but it really helps get heat transfer going.

You're close man, I can feel it

Merry Xmas! I'm out until after

later, Billy! Merry Christmas to you and yours!!

[TreeSlayer]

FYI.... Retrograde rocks! gittin ready to box!

[TreeSlayer]

it occurred to me that if i put the caps in backward on retro, i obviously put them in backward for cupcake... i was right. i've turned them around, the only problem now is i pulled the IC out and i'm still waiting for the new one to show up. wish me luck!! 

[TreeSlayer]

well, IC showed up today. i installed it, and now i don't get the gospel station anymore. all i get is static. man... 

[toneboner]

I went thru it all with my cupcake... easiest build I had tackled to date, and the most problematic. It was a great learning experience but I much prefer my projects to work right out the gate! I ended up having a bad stomp switch, a bad 1n34a, and wrong value for r10 which sets attack time.

check this out for some great advice from oldhousescott: http://www.madbeanpedals.com/forum/index.php?topic=3052.0

I was ready to give up on the damn thing and left it alone for a while to work on other projects. Even went as far as gathering bits for a second build. But eventually the answers came. (actually, had to probe it like a horny alien...)

[midwayfair]

well, IC showed up today. i installed it, and now i don't get the gospel station anymore. all i get is static. man... 

Are you still trying to get just the audio path to work, or did you reconnect the compression path?

[TreeSlayer]

I went thru it all with my cupcake... easiest build I had tackled to date, and the most problematic. It was a great learning experience but I much prefer my projects to work right out the gate! I ended up having a bad stomp switch, a bad 1n34a, and wrong value for r10 which sets attack time.

check this out for some great advice from oldhousescott: http://www.madbeanpedals.com/forum/index.php?topic=3052.0

I was ready to give up on the damn thing and left it alone for a while to work on other projects. Even went as far as gathering bits for a second build. But eventually the answers came. (actually, had to probe it like a horny alien...)

thanks, sasha!

[TreeSlayer]

well, IC showed up today. i installed it, and now i don't get the gospel station anymore. all i get is static. man... 

Are you still trying to get just the audio path to work, or did you reconnect the compression path?

hey, Jon! how were the holidays? great here. actually, i turned the caps around right and reconnected the compression path, feeling like i had it wooped. i can try to adjust the bias, but it just gets more or less staticky. i'm going to double check a couple of things when i get home. i'll holler back... LT

[TreeSlayer]

well, IC showed up today. i installed it, and now i don't get the gospel station anymore. all i get is static. man... 

Are you still trying to get just the audio path to work, or did you reconnect the compression path?

hey, Jon! how were the holidays? great here. actually, i turned the caps around right and reconnected the compression path, feeling like i had it wooped. i can try to adjust the bias, but it just gets more or less staticky. i'm going to double check a couple of things when i get home. i'll holler back... LT

finally! she rocks!!    as soon as i got home i started checking grounds and sure 'nuff, i had a bad one! time to box it! now to get range master runnin!

[midwayfair]

well, IC showed up today. i installed it, and now i don't get the gospel station anymore. all i get is static. man... 

Are you still trying to get just the audio path to work, or did you reconnect the compression path?

hey, Jon! how were the holidays? great here. actually, i turned the caps around right and reconnected the compression path, feeling like i had it wooped. i can try to adjust the bias, but it just gets more or less staticky. i'm going to double check a couple of things when i get home. i'll holler back... LT

finally! she rocks!!    as soon as i got home i started checking grounds and sure 'nuff, i had a bad one! time to box it! now to get range master runnin!

That's great! Sometimes it really is just a matter of taking some time away and coming at it from a fresh perspective.