Capacitors multimeter question

[bifbangpow]

Hey there.  So I'm building a fuzzy bee clone and , of course, it aint working. When I plug it in, the LED sometimes lights for a quick second, but most of the time nothing and no sound.  I realized this was probably a power problem so I got out the multimeter and checked my battery. It was fine.  Then I started checking all the components on the circuit board.  There is one single capacitor that shows no signs of life when I touch it with the multimeter.  All the others like it show power flow on the meter.  Does this mean the part is bad and i should replace it?

[smallbearelec]

Hi--

Please review the "What To Do When It Doesn't Work" article, and post pics and voltage readings here.

[mth5044]

^WhAt he said.

There is a debugging article posted as a sticky on the top of the forum with a guide that helps outline steps for data collecting that help others identify what could be wrong.

It's hard to saw what your problem is, but it could be an intermittent cracked wire, solder bridge, something touching something else. Hard to say! What do you mean by power flow?

[bifbangpow]

Hey there.  So I'm building a fuzzy bee clone and , of course, it aint working. When I plug it in, the LED sometimes lights for a quick second, but most of the time nothing and no sound.  I realized this was probably a power problem so I got out the multimeter and checked my battery. It was fine.  Then I started checking all the components on the circuit board.  There is one single capacitor that shows no signs of life when I touch it with the multimeter.  All the others like it show power flow on the meter.  Does this mean the part is bad and i should replace it?

Hey there.  So I'm building a fuzzy bee clone and , of course, it aint working. When I plug it in, the LED sometimes lights for a quick second, but most of the time nothing and no sound.  I realized this was probably a power problem so I got out the multimeter and checked my battery. It was fine.  Then I started checking all the components on the circuit board.  There is one single capacitor that shows no signs of life when I touch it with the multimeter.  All the others like it show power flow on the meter.  Does this mean the part is bad and i should replace it? If not, what is wrong with my pedal?

Here is  my checklist:
1.What does it do, not do, and sound like? mentioned above.
2.Name of the circuit = Fuzzy Bee V2 (pumped up edition)
3.Source of the circuit (URL of schematic or project) =  http://www.guitarpcb.com/PDF%20Files/Fuzzy%20Bee_v2.pdf
4.Any modifications to the circuit? No.
5.Any parts substitutions? Nope.
6.Positive ground to negative ground conversion? Nope. I don't think so....?
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? =  9v roughly.
Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = .8
Voltage at the circuit board end of the black battery lead =0.0

ON board voltages as follows:

Q1
Balance, Sustain Timbre all measure at o.o

D3:
0.0
0.8
-0.4

ICI: 0.8

D1: 0
D2: 0

C1:
C2: 0.0
C4: 0.0
C5: ... it's all roughly zero. sometimes a .1 that fluctuates to zero.

[duck_arse]

Voltage at the circuit board end of the red battery lead = .8

this is very wrong. it should be the same as the battery voltage. either the clip/lead is bad/open circuit, or you have a short somewhere between supply and ground. switch off, disconnect the battery, and do continuity checks from the battery clip to board (via any jack switching, of course), and from board (+) to board ground. and post your results.

[anotherjim]

Duck just beat me to that!
The out of circuit battery voltage being right isn't proof that you have a good battery - it is a necessary first step before measuring the in-circuit voltage. The very low in-circuit voltage shows either a failed battery or a short circuit somewhere.
You only know you have a good battery if it shows correct voltage while delivering power to something.

Do check that diode D2 is the right way around as per schematic - battery reading 0.8V is suspiciously close to a diode voltage drop. D2 wrong will discharge every battery you attach. It is used deliberately "backward" to short out the power supply IF, and only if, the power supply is connected the wrong way around. Normally, D2 should never conduct.

[bifbangpow]

Redid my troubleshooting readings.  I think I was doing it wrong?
This time I connected my negative multimeter prod to what i think is the ground prong of the input jack.  Is that what I'm supposed to do? Youtube isn't helping much.  When I do that, these are my readings.

Here is  my checklist:

The battery I'm using reads at 9.68... voltage when tested with multimeter probes.

1.What does it do, not do, and sound like? mentioned above.
2.Name of the circuit = Fuzzy Bee V2 (pumped up edition)
3.Source of the circuit (URL of schematic or project) =  http://www.guitarpcb.com/PDF%20Files/Fuzzy%20Bee_v2.pdf
4.Any modifications to the circuit? No.
5.Any parts substitutions? Nope.
6.Positive ground to negative ground conversion? Nope. I don't think so....?
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?- without a battery plugged in, the battery clip terminals reads 0.00 ====

8. Now insert the battery into the clip. If your effect is wired so that a plug must be in the input or output jack to turn the battery power on, insert one end of a cord into that jack. Connect the negative/black meter lead to signal ground by clipping the negative/black lead to the outer sleeve of the input or output jack, whichever does not have a plug in it. With the negative lead on signal ground, measure the following:
Voltage at the circuit board end of the red battery lead = .9.8
Voltage at the circuit board end of the black battery lead =8.8

ON board voltages as follows:

Q1
Balance, Sustain Timbre all measure at 9.2

D1: 9. sometimes 8.73
D2: 9.8
D3:8.19

ICI: 9.7

C1: 9.2
C2: 8.82
C4: 8.72
C5: 8.6
C6: 8.7
C7:  9.8
C8: 9.0
C9: 9.3

Q1: 9.5
Q2: 9.4
Q3: 8.4

Do I need to do the resistors? All of my wiring solder joints look so good, I would be surprised if i needed to resolder one...

[bifbangpow]

Duck just beat me to that!
The out of circuit battery voltage being right isn't proof that you have a good battery - it is a necessary first step before measuring the in-circuit voltage. The very low in-circuit voltage shows either a failed battery or a short circuit somewhere.
You only know you have a good battery if it shows correct voltage while delivering power to something.

Do check that diode D2 is the right way around as per schematic - battery reading 0.8V is suspiciously close to a diode voltage drop. D2 wrong will discharge every battery you attach. It is used deliberately "backward" to short out the power supply IF, and only if, the power supply is connected the wrong way around. Normally, D2 should never conduct.

Im starting to think I don't understand where my ground clip should be with my multimeter. When i had it clasped to the metal of the enclosure... all my readings were near 0.  When I clasp it to what i think is the ground prong of the input jack, all my readings are around 9v.  I've watched lots of instructional videos and still am not sure I'm doing this right. Can you help me?

[mth5044]

Ideally, you should have continuity between a bunch of points that should be connected to ground. If you multimeter has a continuity measurement thing (will give a beep when there is a connection), use it to make sure you have a connection between the two sleeve tabs of the jacks, the enclosure, ground on the circuit, and ground at the power jack. If you don't have the continuity tester, set it on the lowest resistance - there should be very little ohms if they are all connected.

If your enclosure is painted, and you got paint in the holes of the jacks, you could have some problems getting them to make the connection. If you are using insulated jacks, they will not ground the enclosure. When I do measurements, I stick my ground probe into the screw hole on the enclosure. Simple enough

[duck_arse]

the way to measure: put your black probe to ground/0V/earth/battery negative. this is your reference point. any part of the circuit/chassis that connects to ground will do, if you know the connection is good. (see mth50's answer.) then poke your red probe to what you want to measure. it should be a positve (+) reading, because you only have the battery as supply.

I think all reading of 8V5~9V8 indicates that a supply connection is not being made, and yr meter is floating. this is re-inforced by your other set of all 0 readings.

do those continuity checks without the battery, get back to us with results. also photos of your build, if you can.

[bifbangpow]

the way to measure: put your black probe to ground/0V/earth/battery negative. this is your reference point. any part of the circuit/chassis that connects to ground will do, if you know the connection is good. (see mth50's answer.) then poke your red probe to what you want to measure. it should be a positve (+) reading, because you only have the battery as supply.

I think all reading of 8V5~9V8 indicates that a supply connection is not being made, and yr meter is floating. this is re-inforced by your other set of all 0 readings.

do those continuity checks without the battery, get back to us with results. also photos of your build, if you can.

My multimeter doesn't have the continuity setting. At least, not that I can see. 
Also when you say "any point that connects to ground" can you give an example of an exact part i can touch that connects to ground? Just so I know that I'm not misconstruing what you're telling me.

Should I get a better multimeter?

[smallbearelec]

My multimeter doesn't have the continuity setting. At least, not that I can see. 

It might not be called that. Do you have the instruction leaflet? If not, reply with a pic of the range selector.

[Brisance]

My multimeter doesn't have the continuity setting. At least, not that I can see. 

It looks like a dot with some radiation emitting usually:


Also you can always use resistance mode, which is more cumbersome, but will work

[duck_arse]

"any point that connects to ground" - look on your circuit diagram, and anything connected to the little three-stripe triangle symbol is commoned with/to ground, so they all should read 0R between, and 0V difference.

also, my apologies, I now see that is a charge pumped and inverted setup, so except for around the top of the IC being positive voltages, all the readings in the audio section will be negative, with respect to ground (where your black probe will still be).

[bifbangpow]

Here is the multimeter i have. I will try to get you those readings, but i dont have that radiation sign, let me try a similar setting.

[bifbangpow]

ok. So using the lowest resistance setting on my multimeter, i placed my two meter prods on the sleeve lugs of the input jack and the output jack at the same time. That gave me a reading that quickly descended from 30 down to roughly 1.1.   

Then I tested both ends of each wire from joint to joint, and all of the wires seem to get a similar reading.

what other points should i test? Working on uploading some photos.

[bifbangpow]

I should mention that after doing some basic resoldering just in case, the pedal now received power just fine, but still no sound.  The LED lights up, but nothing not even clean signal comes through sound-wise.

Now what should I do?
Maybe my chip fried?

[bifbangpow]

I'm pretty sure it was the IC Chip.  Thank you everyone for being of so much help! I can't really move forward until i get a new chip to replace the old one.  So ... to be continued....

[duck_arse]

on your lowest resistance setting, short the black probe to the red probe. what does the meter indicate? THAT number is what you should regard as "good" for when you expect to measure zero-ohms, like from in sleeve to out sleeve, or in sleeve to board ground.

your next test would be from input-jack tip to output-jack tip. then work the bypass switch. wired correct, it should go from "good" zero-ohms to 'a' number, possibly over-range, at least very high, and maybe counting.

next, if all that works out, test from input-jack tip to circuit board input connection (at the board), and work the bypass. then do the same for the board output and output socket tip. what results?

and then, do you get "-9V" or similar at the output of the charge pump IC when there is +9V at its input pin?

[edit :] and get us those photos! of the offboard parts as well!

[bifbangpow]

on your lowest resistance setting, short the black probe to the red probe. what does the meter indicate? THAT number is what you should regard as "good" for when you expect to measure zero-ohms, like from in sleeve to out sleeve, or in sleeve to board ground.

your next test would be from input-jack tip to output-jack tip. then work the bypass switch. wired correct, it should go from "good" zero-ohms to 'a' number, possibly over-range, at least very high, and maybe counting.

next, if all that works out, test from input-jack tip to circuit board input connection (at the board), and work the bypass. then do the same for the board output and output socket tip. what results?

and then, do you get "-9V" or similar at the output of the charge pump IC when there is +9V at its input pin?

[edit :] and get us those photos! of the offboard parts as well!

ok. So i replaced the chip, and it still doesnt work so we continue.  Id like to follow your instructions but I still have questions. 
1. Should the 9v battery be plugged in when i do this?
2. When i place the black and red probes together on my meter, the number fluctuates rapidly between many random numbers from 90. to 3.3  So i'm not sure, but that doesn't seem right. I'm on my lowest resistance setting of 200 in the resistance/ohm part of my multimeter.
3. when you say "work the bypass switch" do you mean the footswitch? and by "work" do you mean put the black probe to any ground and touch any or all of the lugs individually with the red probe? If not, please be specific.

I realize it's probably frustrating having to explain all this to me.  I taught myself to build all alone in my house just me and the internet, so all though I've built around 10 pedals at this point, there is still so much I don't understand. Specially jargon.

here are some photos of my build. I have replaced the IC chip and made sure its in correctly since taking these.

<a href="https://www.facebook.com/photo.php?fbid=1041503625890023&set=pcb.1041503679223351&type=1&theater"></a>

<a href="https://www.facebook.com/photo.php?fbid=1041503622556690&set=pcb.1041503679223351&type=1&theater"></a>

<a href="https://www.facebook.com/photo.php?fbid=1041503629223356&set=pcb.1041503679223351&type=1&theater"></a>