cupcake problem

[wgc]

Just finished one of these last night...

Anyway, the oversized caps you're using can be tricky, I would probably check there for a short.  Lots of exposed lead that might be touching something it shouldn't.

Also, probably not the issue here, but be careful with the ceramic caps too- it can be easy to stick the lead too far into the hole and not get as good a connection as you might think there.

good luck!

[TreeSlayer]

It is serious, but starting over is not the next step. Analyzing the data just tells us what's wrong, not the next step.

You have power leaking to ground? You should stop the power from leaking to ground. The first step to do that is to find out where power is going to ground.

The usual guess here is that you have a solder bridge between any of your 9V connection points and and of your GND connection points. Luckily, this is a small circuit, so there aren't many of either. Start to examine all of them closely, and even reheat those pads carefully with your iron. Once those pads have been isolated from each other, you may have a working circuit.

Jacob

thanks, Jacob! just starting to get a tad frustrated. i've looked this over several times and can't see anything shorting out. i'm going to try reheating the pads.

it was amazing how things cleaned up after doing this. everything looks tighter and more secure. but still no results. there is no power going to the board in this pic. i have my tester hooked up to the outbound side of the board and the ground hooked up to the groung by the 9v in. with my thumb touching leg #3 on the level pot, i get the local gospel station over my amp. maybe God's trying to tell me something? LOL

[TreeSlayer]

Just finished one of these last night...

Anyway, the oversized caps you're using can be tricky, I would probably check there for a short.  Lots of exposed lead that might be touching something it shouldn't.

Also, probably not the issue here, but be careful with the ceramic caps too- it can be easy to stick the lead too far into the hole and not get as good a connection as you might think there.

good luck!

thanks Billy! i rechecked all of that also. i tried to be really careful when installing them, knowing i had a lot of lead showing. i rechecked anyway, and still nothing. thanks for the luck! gonna need it....

[TreeSlayer]

well, i give up. i don't know what happened. i've gone over this thing at least a dozen times. i would like to thank everyone that took time out of there busy day to try and help. i hope that one day i can return the favor. i ain't quitting though! i now have in my possesion two more cupcake pcb's! i truly believe that even a blind squirrel finds a nut every once in a while! i hope my retrograde dosen't turn out this way....

[midwayfair]

i'd hate to see you give up when it's such a small circuit board.

First, let's narrow down WHAT can be wrong. Audio probe pins 3 and 1. Anything at either?

Next, eliminate the possibility that the 1N4001 is dead. Test it to be sure, maybe even desolder it.

Then, simplify the circuit as much as possible. Pull Q1 and R10 to remove the compression circuitry from the audio path.

Finally, replace the chip. It's soldered to the board, so it's going to suck a little if you don't have a desoldering pump.

I mean, it's a small board, and far be it from me to criticize someone for restarting on it (despite having built a half dozen of these, a Cupcake with a completely buggered board is one of only three things in my box of fail), but I really think that until you've exhausted all reasonable troubleshooting efforts. At some point, it's the pricipal of the thing. We have physics on our side! We're not going to let a bunch of petty resistors push us around? Put on your thinking cap. Live and let diode. Make puns.

[TreeSlayer]

i'd hate to see you give up when it's such a small circuit board.

First, let's narrow down WHAT can be wrong. Audio probe pins 3 and 1. Anything at either?

Next, eliminate the possibility that the 1N4001 is dead. Test it to be sure, maybe even desolder it.

Then, simplify the circuit as much as possible. Pull Q1 and R10 to remove the compression circuitry from the audio path.

Finally, replace the chip. It's soldered to the board, so it's going to suck a little if you don't have a desoldering pump.

I mean, it's a small board, and far be it from me to criticize someone for restarting on it (despite having built a half dozen of these, a Cupcake with a completely buggered board is one of only three things in my box of fail), but I really think that until you've exhausted all reasonable troubleshooting efforts. At some point, it's the pricipal of the thing. We have physics on our side! We're not going to let a bunch of petty resistors push us around? Put on your thinking cap. Live and let diode. Make puns.

ok, Jon! i know i can do this. i can build a drag car from the ground up, literally. engine, transmission, rear end, chassis, electrical, and even a little paint and body. once i start understanding how things work and why, this will get easier. i love a challenge!
first thing though, i'm not sure what audio pins 3 and 1 are. is it in ic1?

[midwayfair]

i'd hate to see you give up when it's such a small circuit board.

First, let's narrow down WHAT can be wrong. Audio probe pins 3 and 1. Anything at either?

Next, eliminate the possibility that the 1N4001 is dead. Test it to be sure, maybe even desolder it.

Then, simplify the circuit as much as possible. Pull Q1 and R10 to remove the compression circuitry from the audio path.

Finally, replace the chip. It's soldered to the board, so it's going to suck a little if you don't have a desoldering pump.

I mean, it's a small board, and far be it from me to criticize someone for restarting on it (despite having built a half dozen of these, a Cupcake with a completely buggered board is one of only three things in my box of fail), but I really think that until you've exhausted all reasonable troubleshooting efforts. At some point, it's the pricipal of the thing. We have physics on our side! We're not going to let a bunch of petty resistors push us around? Put on your thinking cap. Live and let diode. Make puns.

ok, Jon! i know i can do this. i can build a drag car from the ground up, literally. engine, transmission, rear end, chassis, electrical, and even a little paint and body. once i start understanding how things work and why, this will get easier. i love a challenge!
first thing though, i'm not sure what audio pins 3 and 1 are. is it in ic1?

Yes, use an audio probe on pins 1 and 3 of the IC. If you haven't built an audio probe, I think there's a post about it in the tech help thread. It's really easy.

[wgc]

It's a very cool little circuit, worth the effort!

Totally agree you might have a bad component.

Dont give up, this stuff is way easier than building a car, same troubleshooting applies, just different tools.

[TreeSlayer]

i'd hate to see you give up when it's such a small circuit board.

First, let's narrow down WHAT can be wrong. Audio probe pins 3 and 1. Anything at either?

Next, eliminate the possibility that the 1N4001 is dead. Test it to be sure, maybe even desolder it.

Then, simplify the circuit as much as possible. Pull Q1 and R10 to remove the compression circuitry from the audio path.

Finally, replace the chip. It's soldered to the board, so it's going to suck a little if you don't have a desoldering pump.

I mean, it's a small board, and far be it from me to criticize someone for restarting on it (despite having built a half dozen of these, a Cupcake with a completely buggered board is one of only three things in my box of fail), but I really think that until you've exhausted all reasonable troubleshooting efforts. At some point, it's the pricipal of the thing. We have physics on our side! We're not going to let a bunch of petty resistors push us around? Put on your thinking cap. Live and let diode. Make puns.

ok, Jon! i know i can do this. i can build a drag car from the ground up, literally. engine, transmission, rear end, chassis, electrical, and even a little paint and body. once i start understanding how things work and why, this will get easier. i love a challenge!
first thing though, i'm not sure what audio pins 3 and 1 are. is it in ic1?

Yes, use an audio probe on pins 1 and 3 of the IC. If you haven't built an audio probe, I think there's a post about it in the tech help thread. It's really easy.

i built the tester first. i'm assuming in the pic that i'm pointing to #8, then moving up to the next pin would be 7, 6, then 5. moving to the pin to the right of 8 would be 4, 3, 2 then 1 at the top

[TreeSlayer]

It's a very cool little circuit, worth the effort!

Totally agree you might have a bad component.

Dont give up, this stuff is way easier than building a car, same troubleshooting applies, just different tools.

thanks for the vote of confidence, Billy!

[TreeSlayer]

i'd hate to see you give up when it's such a small circuit board.

First, let's narrow down WHAT can be wrong. Audio probe pins 3 and 1. Anything at either?

Next, eliminate the possibility that the 1N4001 is dead. Test it to be sure, maybe even desolder it.

Then, simplify the circuit as much as possible. Pull Q1 and R10 to remove the compression circuitry from the audio path.

Finally, replace the chip. It's soldered to the board, so it's going to suck a little if you don't have a desoldering pump.

I mean, it's a small board, and far be it from me to criticize someone for restarting on it (despite having built a half dozen of these, a Cupcake with a completely buggered board is one of only three things in my box of fail), but I really think that until you've exhausted all reasonable troubleshooting efforts. At some point, it's the pricipal of the thing. We have physics on our side! We're not going to let a bunch of petty resistors push us around? Put on your thinking cap. Live and let diode. Make puns.

ok, Jon! i know i can do this. i can build a drag car from the ground up, literally. engine, transmission, rear end, chassis, electrical, and even a little paint and body. once i start understanding how things work and why, this will get easier. i love a challenge!
first thing though, i'm not sure what audio pins 3 and 1 are. is it in ic1?

Yes, use an audio probe on pins 1 and 3 of the IC. If you haven't built an audio probe, I think there's a post about it in the tech help thread. It's really easy.

i built the tester first. i'm assuming in the pic that i'm pointing to #8, then moving up to the next pin would be 7, 6, then 5. moving to the pin to the right of 8 would be 4, 3, 2 then 1 at the top

welp, looks like i made an ass of me.:{P the pin im pointing at is #1. i finally found a pin id chart. when i touch #1 or #3 for the first time, i get a loud pop through my amp. my cat about jumped out of her skin. i checked D2 and it's good. i'm on the hunt for a desoldering pump now. solder wick just ain't cuttin it.

[TreeSlayer]

i'd hate to see you give up when it's such a small circuit board.

First, let's narrow down WHAT can be wrong. Audio probe pins 3 and 1. Anything at either?

Next, eliminate the possibility that the 1N4001 is dead. Test it to be sure, maybe even desolder it.

Then, simplify the circuit as much as possible. Pull Q1 and R10 to remove the compression circuitry from the audio path.

Finally, replace the chip. It's soldered to the board, so it's going to suck a little if you don't have a desoldering pump.

I mean, it's a small board, and far be it from me to criticize someone for restarting on it (despite having built a half dozen of these, a Cupcake with a completely buggered board is one of only three things in my box of fail), but I really think that until you've exhausted all reasonable troubleshooting efforts. At some point, it's the pricipal of the thing. We have physics on our side! We're not going to let a bunch of petty resistors push us around? Put on your thinking cap. Live and let diode. Make puns.

ok, Jon! i know i can do this. i can build a drag car from the ground up, literally. engine, transmission, rear end, chassis, electrical, and even a little paint and body. once i start understanding how things work and why, this will get easier. i love a challenge!
first thing though, i'm not sure what audio pins 3 and 1 are. is it in ic1?

Yes, use an audio probe on pins 1 and 3 of the IC. If you haven't built an audio probe, I think there's a post about it in the tech help thread. It's really easy.

i built the tester first. i'm assuming in the pic that i'm pointing to #8, then moving up to the next pin would be 7, 6, then 5. moving to the pin to the right of 8 would be 4, 3, 2 then 1 at the top

welp, looks like i made an ass of me.:{P the pin im pointing at is #1. i finally found a pin id chart. when i touch #1 or #3 for the first time, i get a loud pop through my amp. my cat about jumped out of her skin. i checked D2 and it's good. i'm on the hunt for a desoldering pump now. solder wick just ain't cuttin it.

ok. Q1 is pulled and i desoldered one end of R10. before it didn't matter if the test box was on or off, i got the music. now it comes when i turn the tester on, and slowly goes away when i turn it off.

[wgc]

Solder wick works better if you add solder to the braid and joint when you start with it, gets the capillary action going.  Then just slide it along until your joint is desoldered.

If you've got a 2nd ic, clip the leads topside close to the ic body, and then heat them and remove one at a time.  Then wick out the holes and start over.

Also, make sure your iron isnt too hot so you don't cook the new ic.

[TreeSlayer]

Like Jon said , resistance will read differently when in circuit if there are other resistances in the same circuit .
In that case 211.9 k looks normal .

Start by taking voltages of each pins of the ic and the transistors .

i've checked every pin on the bottom if pcb and i have voltage of some degree at all of them.

sorry... i was gettin a little antsy there... here's the readings i got...

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.

[TreeSlayer]

Solder wick works better if you add solder to the braid and joint when you start with it, gets the capillary action going.  Then just slide it along until your joint is desoldered.

If you've got a 2nd ic, clip the leads topside close to the ic body, and then heat them and remove one at a time.  Then wick out the holes and start over.

Also, make sure your iron isnt too hot so you don't cook the new ic.

hey, Billy! after wasting a trip to my local Harbor Freight store, i came back and tried some more with the wick. you're right! if you get some heat into the wick, i really soakes it up! thanks a million for the tip!