Tonepad Small Clone Debug help please

[jkokura]

Alrighty, second project also not working like it's supposed to. Checked the wiring, and it looks like it's supposed to as far as I know, checked some continuity, wished I had an audio probe, and then got all the data you guys would need.


1.What does it do, not do, and sound like?

Sound at Bypass. No sound when active, no light up from the LED.

2.Name of the circuit

Tonepad Small Clone Chorus

3.Source of the circuit (URL of schematic or project)

http://www.tonepad.com/getFile.asp?id=97

4.Any modifications to the circuit? Y or N

Nope

5.Any parts substitutions? If yes, list them.

Nope

6.Positive ground to negative ground conversion? Y or N

I don't know how to tell this, so if someone can tell me how...

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? =>

9.08

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

9.02

Voltage at the circuit board end of the black battery lead =

0

Now, using the original schematic as a reference for which part is which (that is, which transistor is Q1, Q2, etc. and which IC is IC1, IC2, C1, and so on) measure and list the voltage on each pin of every transistor and IC. Just keep the black lead on ground, and touch the pointed end of the red probe to each one in turn. Report the voltages as follows:

Q1
1 = 0
2 = 0
3 = 0

Q2
1 = 2.665
2 = 3.22
3 = 8.72

Q3
1 = 8.07
2 = 8.69
3 = 8.72

IC1 JRC4558D
P1 4.23
P2 4.26
P3 4.15
P4 0
P5 4.25
P6 4.25
P7 4.25
P8 8.55

IC2 LM358
P1 1.74
P2 3.95
P3 3.92
P4 0
P5 2.18
P6 2.14
P7 3.64
P8 8.67

IC3 CD4047BCN
P1 7.7
P2 0.1
P3 7.0
P4 7.85
P5 7.85
P6 7.85
P7 0
P8 0
P9 0
P10 3.94
P11 3.94
P12 0
P13 7.7
P14 7.84

IC4 MN3007
P1 7.99
P2 4.01
P3 1.8
P4 0
P5 0
P6 4.01
P7 3.29
P8 3.29

D1
A (anode, the non-band end) = 1.81
K (cathode, the banded end) = 0

D2
A = 1.08
K = 7.01

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Please Help.

[Shepherd]

The Small Clone is an ambitious circuit for project number 2.

Judging by the pics I would look for solder bridges...and while you're at it look for cold solder joints.

Get it to work with just the battery.  (Take out unessential elements like the bypass switch, AC adapter, and LED.)

Get an audio probe.  All you need is a crappy guitar cable and a crappy amplifier.  You could even make one out of an old boombox.

[jkokura]

I got 5 projects from Tonepad, the squeezer, rosscomp, tubescreamer, Small Stone and Small Clone. So far. I've only fully assembled the squeezer, ross and clone, and none of them are working. I'm short an LED for the Stone so that's waiting until I get the replacement part, and the tubescreamer will have to wait until these three are working.

The worst part is my amp and guitar aren't here at home where i'm building. As for an audio probe, I will in the future get one going, but I don't have one now. As for getting it working with just the battery, I'm not convinced that I would be able to make it work when I have to add in the rest of componants, so I'd rather do it with everything rather than just some of it.

Is there anything wrong with the numbers I put up? Other than that I will look at the solder joints, but I couldn't find any bridges. So far nothing has come up cold using my DMM with continuity.

Jacob

[petemoore]

Q1
1 = 0
2 = 0
3 = 0
  This ones not getting any voltage on it, test for resistance between Collector and V+ [or what goes 'up' toward V+..

Q2
1 = 2.665
2 = 3.22
3 = 8.72
  I can't tell which pin is emitter, base or collector.
Q3
1 = 8.07
2 = 8.69
3 = 8.72  These voltages are clustered so closely, I'd have to study but otherwise assume the transistor isn't baised.
IC1 JRC4558D
P1 4.23
P2 4.26
P3 4.15
P4 0
P5 4.25
P6 4.25
P7 4.25
P8 8.55
  These look biased, the signal pins are all close to 1/2 V of Supply, Gnd+ 0v.
  There's an LFO...Better off letting someone else comment, not sure what the voltages should look like, Q1 and Q3 look like signal stoppers.
IC2 LM358
P1 1.74
P2 3.95
P3 3.92
P4 0
P5 2.18
P6 2.14
P7 3.64
P8 8.67
  IC3 CD4047BCN
P1 7.7
P2 0.1
P3 7.0
P4 7.85
P5 7.85
P6 7.85
P7 0
P8 0
P9 0
P10 3.94
P11 3.94
P12 0
P13 7.7
P14 7.84

IC4 MN3007
P1 7.99
P2 4.01
P3 1.8
P4 0
P5 0
P6 4.01
P7 3.29
P8 3.29

[jkokura]

Q1
...
  This ones not getting any voltage on it, test for resistance between Collector and V+ [or what goes 'up' toward V+..

Q2
...
  I can't tell which pin is emitter, base or collector.
Q3
...
These voltages are clustered so closely, I'd have to study but otherwise assume the transistor isn't baised.
IC1 JRC4558D
...
  These look biased, the signal pins are all close to 1/2 V of Supply, Gnd+ 0v.
  There's an LFO...Better off letting someone else comment, not sure what the voltages should look like, Q1 and Q3 look like signal stoppers.

I appreciate this very much, and will look into solving the problems - but the thing is, I'm not sure what to do cause I'm not sure what some of that means. I've been reading about this stuff for months, trying to get as much knowledge so I can understand, but I only am picking up a little bit of what you're saying. If you could give me some steps to take to deal with the problems you see I think I would be able to handle that.

[petemoore]

  Whoops, I went in over my head and got myself in the ringer !
  Q1 collector goes to ground, I don't know what these transistors are doing.
  Except to say Q1 isn't doing anything if it's pins stay at 0 volt the whole time.
  .

[jkokura]

Gentle Bump. I'm continuing to work on this and have yet to find a full solution to why it's not working, so if anyone sees anything not mentioned yet...

[george]

Have you tried adjusting the trimmer?   This needs to be done to set the bias voltage to the BBD otherwise there won't be any delayed signal mixed in with the dry signal to give you chorusing.