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Following on from an initial layout problem, I've started this thread specifically for my debugging issue...

Hopefully someone can shed some light :)

The layout is www.sabrotone.com/wp-content/uploads/2011/05/EchoBase.gif

The effects appear to be working on something (ambient noise / static?) as i can increase feedback, level, time etc but no guitar signal.

I get clean bypass signal if i use the main switch i installed with led but nothing else. The switch i used is http://www.sabrotone.com/wp-content/uploads/2013/01/True_bypass_battery.png

I've started poking around with an audio probe and my clean input signal reaches pins 5,6,7 of IC2.  Also reaches R32 but doesnt pass through. However the signal reaches R21.

I've removed and re-solderdered IC2 just in case and have probed with multimeter.  Still having same problems with audio probe stopping very early on in the circuit.

Substituted Parts:
- R6 used 2x 120k in series
- Q2 used BC109
- Q3 USED 2N5088

Below are the results of meter readings, hopefully they mean more to someone than they do to my novice eyes.  A few 0v readings on Q2, IC3 and D1 if that means anything?:

Battery 8.4
Red 9v+ 5.35
Black lead -1.63

Q1
C 7.68
B 7.63
E 7.63

Q2
C 0
B 0
E 7.03

Q3
C 7.52
B 7.51
E 7.66

Ic1
1 7.73
2 7.29
3 7.69
4 7.54
5 7.8
6 7.08
7 7.72
8 7.36

Ic2
1 7.3
2 7.31
3 7.72
4 7.73
5 7.82
6 7.77
7 7.77
8 7.33

Ic3
1 7.46
2 7.43
3 7.42
4 7.47
5 7.65
6 7.34
7 7.77
8 7.83
9 7.65
10 0
11 0
12 0
13 7.83
14 7.76

Ic4
1 7.82
2 7.83
3 7.83
4 7.83
5 7.32
6 7.77
7 7.45
8 7.45
9 7.51
10 7.47
11 7.56
12 7.55
13 7.55
14 7.54
15 7.5
15 7.5

D1
A 0
K 7.85

D2
A 8.3
K 7.77

D3
A 7.77
K 8.04

> Ic1
> 1 7.73
> 2 7.29
> 3 7.69
> 4 7.54
> 5 7.8
> 6 7.08
> 7 7.72
> 8 7.36
> Ic2
> 1 7.3
> 2 7.31
> 3 7.72
> 4 7.73
> 5 7.82
> 6 7.77
> 7 7.77
> 8 7.33

All your opamp pins are at plus battery voltage. At least one MUST be at negative battery (typically zero volts), several others should then be half battery voltage.

Find your missing ground connection.

Thanks!  I've since cleaned up a bunch of solder joints just to be extra vigilant but still no luck :( The audio probe now only has signal on IC2 point 8 (I'm guessing the signal doesn't travel through resistors right?).

New meter readings are:
Ic1
1 8.06
2 7.63
3 8.11
4 8.11
5 8.15
6 7.41
7 8.1
8 7.69

Ic2
1 7.68
2 7.68
3 8.1
4 8.1
5 8.14
6 7.67
7 7.68
8 7.7

What could the missing ground connection be?

P.S - Sorry for my electronics naivety and thankyou very much for your help.  It is VERY much appreciated and hopefully once this is working I'll be a lot more aware for the next project.

Is there a schematic? Link?

Here's the one I used:

http://www.sabrotone.com/wp-content/uploads/2011/05/EchoBase.gif

Schematic, not layout.

Something like this, only different:

(http://t2.gstatic.com/images?q=tbn:ANd9GcTHZu_taeS0oE5UErBXFHdUOuYTcg_H2hx4VYYax08MIkvOkO00hQ)

Unfortunatly I can't find one.  My skills only allow me to follow vero layouts.

Any thoughts on this? I think my own debugging has hit a wall :(

Chuck one end of a wire to GND, put a signal through the engaged effect and poke things with the other end of the wire.

It's not getting any less dead staring at it!

(This may not in fact be a good idea, but I do this as a last resort... as a sacrifice ritual in most cases).

Thanks, I've already used an audio probe to similar effect.  No luck though :(

Really don't want to throw the towel in. Any further suggestions are very welcome.

Like Paul said you appear to have no ground connection. Where have you connected the point marked "ground" on the vero to? When you're measuring the voltages do you have a lead plugged into the input jack? It won't work without one.
You shouldn't be using true bypass with the Echo Base if you want to use the tails feature but we can worry about that once you've got it working.
For a schematic go to  musicpcb.com

Cool, I've spent the last few hours going over every component and joint... Embarrassingly discovered two missing cuts, a misplaced cap point and a backward transistor!  Now everything is DEFINTLY in place though and I've since discovered that soldering a project a big as this in one go just makes mistakes.

I've now got signal that passes through the circuit and gets effected BUT it is very low-fi, quiet and only allows one delay.

I'm almost there, I can feel it in my bones :)

Just collecting voltage readings again now, but if anyone can suggest anything in the meantime, it's greatly appreciated.

Updated Voltage readings below if anyone can interpret?

Battery      7.98

IC1
1 6.02
2 5.16
3 4.97
4 5.57
5 5.01
6 4.97
7 5.73
8 7.63


IC2
1 4.97
2 4.97
3 4.96
4 0.1
5 4.49
6 4.97
7 4.97
8 7.83

IC3
1 0.55
2 0.55
3 0.55
4 0.55
5 0.6
6 0.54
7 0
8 7.81
9 0.6
10 0
11 0
12 0
13 0.15
14 0.83

IC4
1 4.97
2 2.42
3 0
4 0
5 3.2
6 2.42
7 0.57
8 0.63
9 2.42
10 2.42
11 2.42
12 2.42
13 2.42
14 2.4
15 2.42
16 2.41

Q1
In 7.76
Gnd 0.0
Out 4.96

Q2
E 0
B 0.6
C 1.17

Q3
C 2.41
B 0
E 0

Quote from: maurice on July 17, 2013, 06:47:45 AM
IC1
1 6.02
2 5.16
3 4.97
4 5.57
5 5.01
6 4.97
7 5.73
8 7.63

This is still off.  Pin 4 should be 0V (ground).

> ... Embarrassingly discovered two missing cuts, a misplaced cap point and a backward transistor!  Now everything is DEFINTLY in place....

Experience says if there is a bad joint, it is not alone.

As Marc points out, pin 4 sure aint right, which should be "simple"; and I suspect that's not the last problem.

I'll gleefully admit that I once found and fixed a dozen problems, the dingus still didn't work, and it took me MONTHS to find the last critical mistake (and then some more minor errors). Experience makes you better, they say; I've become sometimes good at finding my mistakes, but last month I tried to sort some wiring and ended up sealing it into the wall un-fixed.

Quote from: PRR on July 17, 2013, 11:29:50 PM
but last month I tried to sort some wiring and ended up sealing it into the wall un-fixed.

Is that like the time I "Dropped" my TI scientific calculator due to frustration, and once I'd fished it out of the space between the gyprock sheets that divide the rooms in that house... except without the part where you get it back out?

Ha, I'm hoping I don't get to the burying stage just yet.

I've just been goin over any joint that look as though they could be bad.  Also, taken out the true bypass switch (now have no switch at all) but still have quiet, lo-fi sound but some of the voltage have changed?  Do these new results suggest problems to anyone?

Battery      7.92

IC1
1 6.49
2 5.44
3 4.97
4 5.56
5 5
6 4.97
7 5.84
8 0.02


IC2
1 4.97
2 4.97
3 4.94
4 0
5 4.48
6 4.97
7 4.93
8 7.89

IC3
1 0.64
2 0.66
3 0.66
4 0.67
5 0.71
6 0.65
7 0
8 0.92
9 0.27
10 0
11 0
12 0
13 0.82
14 7.88

IC4
1 4.96
2 2.42
3 0
4 0
5 3.17
6 2.42
7 0.72
8 0.72
9 2.42
10 2.40
11 2.41
12 2.42
13 2.42
14 2.42
15 2.42
16 2.42

Q1
In 7.86
Gnd 0
Out 4.97

Q2
E 0
B 0.6
C 1.17

Q3
C 2.42
B 0
E 0

Just reading what others have said, and looking at your recent repost - you still have something wrong at IC1 pin4... solder bridge?

(Note - I'm just reinterpreting smart people).

hmmmm, weird. I've the connection from gnd to IC1 pin 4 seems good (checked continuity and ohms).  What could be making it such a high voltage?

also, the led isn't working if that suggests an obvious problem.  Does it need a resistor?

The LED  doesn't need a resistor, to turn the LED on you need to ground "bypass sw 1" this enables the delay. If bypass sw1 isn't grounded the effect is in bypass and you should just hear clean sound.
For your opamp voltage problem, check that the bottom of R8 has continuity to ground and that the top has continuity to pin4 of the opamp, also check that its value is 220 Ohms. This problem shouldn't stop the delay working just the modulation.

still stumped... can't find any unwanted solder bridges.  Been 'round that board a few times with continuity tester :(

Can you do some high-resolution, in-focus pictures of the top and bottom of your board, and one of the board with all its associated wiring?

No problems, heres some images http://www.flickr.com/photos/99178414@N02/sets/72157634720151023/ (http://www.flickr.com/photos/99178414@N02/sets/72157634720151023/)

Nice pictures, very useful. First thing you need to do is connect "Dry SW 1" to "Dry SW 2", with no connection between them you won't have any dry signal. Do that and then hopefully with the effect in bypass you'll get a nice clean signal, let us know if that works and we can then start looking at the rest of the problems.

thanks Slacker.  Dry SW1&2 connected and there's a nice clean signal but also the very quiet ghost signal of a delay.  Still no LED

Still no luck with the intended effects, but one step closer I guess

Any further thoughts?

Guess I'll have to give up on this one, felt so close too :(

No don't give up just yet. If you haven't got one already make yourself an audio probe as shown here http://www.diystompboxes.com/wiki/index.php?title=Debugging (http://www.diystompboxes.com/wiki/index.php?title=Debugging) this lets you play your guitar or an MP3 player or something through the pedal and trace the signal.
We know you're getting a dry signal so we'll assume that's Ok for now so probe the following places, to see where the delayed signal is going wrong.

Put the level pot at 100%, time at 50% and feedback, mod depth and speed at zero. This should just give one repeat to the delay.

Both ends of C6, Pin 3 of IC3 (row o, column 10), pin 4 of IC3 (row n, column 10), both ends of C4, both ends of C18. At all of those points you should get the dry signal.
Pin 15 of IC4 (row m, column 26) you should get a loud signal.
Pin14 of IC4 (row n, column 26) you should get a loud signal.
Both ends of C10,  Pin 2 of IC3 (row p, column 10), Pin 1 of IC3 (row q, column 10), both ends of C3, both ends of C22. You should get the delayed signal at all those points.

Let us know what you find and we can go from there.

Ok, thanks for the support.  It is VERY much appreciated. Here's the results:

C6: e21=dry signal, g21=dry signal but weaker and with buzzing/interferance
Pin 3 of IC3 (row o, column 10): same noisy dry signal as C6 (g21)
pin 4 of IC3 (row n, column 10): as above
C4: both ends as above
C18: p31=as above, q31=VERY faint dry signal with intense buzz

Pin 15 of IC4 (row m, column 26): Loud signal with delay but with buzzing/noise

Pin14 of IC4 (row n, column 26): As above bute even louder

C10: both ends=Delayed signal but very noisy
Pin 2 of IC3: Quiet, very tinny/noisy but delayed
Pin 1 of IC3: As above nut quieter
C3: Both ends very quiet signal but loud buzzing noise
C22: D34=can hear delayed signal but LOTS of buzzing, E34=same but quieter delayed signal

So, in summary the guitar signal gets weaker and the high pitch buzzing/interferance gets louder :(  The degredation and buzzing seems to start at C6 but I've swapped the component to eliminate that section... Any suggestions what may be the culprit?

Ok, it looks like there might be a problem round the CD4066. Please can you measure the voltages on all the pins of that chip again, the last measurements you gave for it, shown below, are almost all wrong so you could have a bad chip.

IC3
1 0.64
2 0.66
3 0.66
4 0.67
5 0.71
6 0.65
7 0
8 0.92
9 0.27
10 0
11 0
12 0
13 0.82
14 7.88

Ok, I've swapped IC3 for a new chip just incase but the effect still isn't right.  Here's the new voltage readings.  Hopefully they will help the diagnosis:

Battery = 8.96

IC3:
1 4.59
2 4.59
3 4.6
4 4.6
5 8.76
6 0.63
7 0
8 7.57
9 00.01
10 0
11 0
12 0
13 8.75
14 8.95

This thing is starting to give me sleepless nights :)

Any suggestions why I'm getting the weak effect with buzzing as per previous post?

Dont give up.
There's none better placed to help you than the good people here.
I still have some builds that want debugging from months ago but i'm confident i will get them going when i put my mind to it and with some kind help.
I've never built this one so i'm affraid im not much use in that respect, but keep your chin up it'll work eventually.
Rich

Your voltages for the CD4066 look correct now, are you still getting the same results if you do the audio probe tests?

Thanks again.  I'm not sure what my recent tinkering has done but I now have a working delay effect (with no interference).

Here's a sample of sound https://soundcloud.com/user485777105/ecdho-base-delay (https://soundcloud.com/user485777105/ecdho-base-delay)

I've still got a few issues but the end is in sight :)

Anyone have advice to solve the following:
- LED won't come on
- Need to speed up the lowest delay time
- Mod speed pot doesnt do anything at all
- Mod depth seems to do the same as feedback (increase repeats)
- Not sure what Humbucker SW is supposed to do but when connected it just makes a crazy loud repeating noise

Also don't know if it's relevant but I just realised I used a 470k pot for the mod speed pot instead of 1m.  Would it have any impact on my problems? I tried using a 1m VR instead to see what'd happen but no changes.

Any suggestions?

Sounds good. Hopefully the rest of the problems shouldn't be too hard.

Quote
LED won't come on

Get your meter and measure the voltage on pin 9 of the CD4066, when the pedal is bypassed you should get a low voltage, it looks like you do from your last readings. When the delay is on, you should get about 1.5 to 2 volts depending on the LED you used, if you get a lot higher than this then either the LED has no connection to ground, it's backwards or it's damaged. If you still get a very low voltage then something else is wrong.

Quote
- Need to speed up the lowest delay time
- Mod speed pot doesnt do anything at all

These are probably because you still have a problem with IC1, can you measure the voltages on all the pins again and let us know what they are.

Quote
- Mod depth seems to do the same as feedback (increase repeats)

Mod depth shouldn't do that, it will change the delay time it can't affect the repeats. I would double check the wiring.

Quote
- Not sure what Humbucker SW is supposed to do but when connected it just makes a crazy loud repeating noise

The humbucker switch connects D2 and D3, these clip loud signals from the delay. It shouldn't do what yours does, again check the wiring and make sure you haven't missed any trace cuts or have any other problems round that area.

Quote
Get your meter and measure the voltage on pin 9 of the CD4066, when the pedal is bypassed you should get a low voltage, it looks like you do from your last readings. When the delay is on, you should get about 1.5 to 2 volts depending on the LED you used, if you get a lot higher than this then either the LED has no connection to ground, it's backwards or it's damaged. If you still get a very low voltage then something else is wrong.

When bypassed, the LED comes on (not sure why) but pin 9 of the 4066 reads at 1.7.  When effect is on, I get 0v.  Have checked that the LED is correct way round and is working though.

Quote
These are probably because you still have a problem with IC1, can you measure the voltages on all the pins again and let us know what they are.

IC1 voltage readings:
1 5.7
2 4.9
3 4.9
4 5.5
5 5
6 4.9
7 4.7
8 8.2

Hopefully these help :)
I've double checked all wiring again, resoldered IC1 and clipped any long wires hoping any of those may help too but no luck.

P.S  Thanks Slacker, this is one huge learning curve and I'll probably owe you a beer after this :)

polite Bump  ;)

Always happy to except a beer, virtual or otherwise  :)

Just been looking back through the thread and noticed this "Q3 USED 2N5088" that's an NPN transistor, Q3 should be PNP, you need to change that before the modulation will work properly. Still need to fix IC1 first though, the voltage on pin 4 is way too high, it should be less than a volt. Are you sure R8 is 220 Ohms, it's hard to tell in the photos but it looks the same same as R10, which is 220K Ohms. If it's 220 Ohms and is definitely connected to pin 4 of IC1 at one end and ground at the other, then I would try replacing IC1.

Thanks, you're right I used a 220k instead of 220r.  My bafoonery astounds me!

Will also replace IC1 and Q3.  Any recomended substitutions for Q3?  Don't have a 2N5087.  If not I'll re-order the part and let you know how it goes.

Without a schematic I'm shooting blind.

But it does not make sense for IC1 pin 4 to be anything except dab-smack ZERO.

Yet the layout shows no clear path to zero voltage (ground).

Has this layout worked for anybody else?

Here's the schematic  http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/album170/echobaserev2.png.html (http://www.aronnelson.com/gallery/main.php/v/slackers-stuff/album170/echobaserev2.png.html) IC1 on the layout is the LFO. Note, the layout uses different sections of the CD4066 to the schematic.

For the PNP BC560 or 2N3906 both work fine.

> it does not make sense for IC1 pin 4 to be anything except dab-smack ZERO.

As someone up-thread said, pin 4 has to be "less than 1V".

I still say the 220 resistor from pin 4 to Ground does not make sense, but it is there, and should work, IF the 220r goes to ground. 

Yes, you're right Paul, it probably doesn't make sense. I designed this 6 years ago when I knew a lot less about this stuff than I do now. It was an attempt to isolate the LFO from the supply to stop ticking, it seemed to work, so I went with it.
This version of the pedal also includes a number of mods and fixes to problems that people found once it was released into the wild. There's a number of things I'd do differently if I was starting from scratch today.

OK, so my parts JUST arrived from China... I've since replaced IC1 with a different chip and now used a 2N3906 for Q3.

It all seems to be working apart from the mod pots have no effect on the sound whatsoever.  The LED only comes on if I link Bypass SW1 to GND but it does pulse based on the position of the mod speed pot.

Almost there... any suggestions?

The LED is supposed to come on when the bypass is grounded, that is effect on, ungrounded is effect off. I noticed from your photos you didn't seem to have the tails switch fitted, you need that fitted before the bypass switch will actually turn the delay on and off, without it the bypass will just turn the LED on and off.
If the LED is flashing that means you have solved your IC1 problem, if the mod depth pot does nothing check all the connections between pin 1 of IC1 and the base of the 2N3906.

Right, I've just had time to return to this project but I'm still having trouble.  Now I've fitted a tails switch and connected bypass to gnd but while the LED flashes in response to both Mod pot positions it does not effect the sound.

I've checked connections from pin1 of IC1 and the base of the 2N3906 but cant see any obvious issues.  Any suggestions or advice?

P.S, just wanted to double check I wired tails switch correctly... Tails2 in the middle of switch with 1&3 at either end?

any suggestions?

Yes the tails switch wiring sounds correct, does it work?

On the modulation problem, if you turn the delay time down all the way do you get a very short delay like a chorus sound or do you still get quite a long delay?

ues tails switch is working but still no mod effects.

When delay is turned down I get a very short delay.  Any ideas how i could get mod speed & depth working on the audio?

Hi folks, does anybody have any suggestions as to why the mod effects are still not working as per previous post?

Any new thoughts on this one?  I'm struggling to beat the final hurdle :)

I think you said before that the LED flashed and the speed of the flashing could be controlled by the mod speed pot, so we know the LFO is working. Something must be wrong some where between the LFO and the PNP transistor. See if you can trace the modulation signal from pin 1 of IC1, through R6 and C24 to lug 3 of the mod depth pot. You should be able to measure about 1.5 to 2 Volts on lug 3, modulating in time with the LED. If you get signal there see if it appears on the wiper of the mod depth pot, turned all the way down you should measure 0 Volts and all the way up the same as lug 3. Then follow it through, R11 to the base of the PNP transistor. Also check R16 is the correct value, check the time pot is connected correctly and check for any missing trace cuts or jumpers around the PNP.

Hopefully one of those things should find the problem.

I'm sure I've had the LED pulsating a few months back (perhaps before replacing components or re-soldering connections) but now it just stays on when bypass is connected to GND.

Before I follow the steps from previos post (following from pin 1 of IC1), what could I do to resolve the LED problem of not showing the modulation?

ok, so I'm a bit embarressed that a fresh 9v battery solved the LED not flashing problem (more power was required for the LFO).

Measurements taken from IC1 through to wiper of Mod speed are fine and fluctuate in time with the LED.

Mod Depth is fluctuating between 4.9-6v but does not read zero when tuned down, so I guess there's a problem here...  What can I check for that?

I see you've found the low battery notification  ;D this is a flaw in the design where the LFO stops working with a weak battery.

Sounds like you don't have the anti clockwise lug (lug 1) of the mod depth connected to ground.

Ground seems to be connected to lug 1 of mod depth and I've tested continuity.  ANything else I could try?

Turn the mod depth pot all the way down and check for continuity between lug 2 and ground, if you don't get continuity then you have either a bad connection from lug 1 to ground or a bad pot.

continuity seems to be good on lug 2 to gnd for mod depth.  Any other suggestions?

I'm confused now then  ??? if you have continuity between lug 2 and ground when it's turned all the way down then you must get zero volts but you said "Mod Depth is fluctuating between 4.9-6v but does not read zero when tuned down," was this measuring from lug 2?