Echo Base Debugging

[slacker]

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.

[maurice]

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

[bluebunny]

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?

[maurice]

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

[slacker]

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.

[maurice]

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

[maurice]

Any further thoughts?

[maurice]

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

[slacker]

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 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.

[maurice]

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?

[slacker]

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

[maurice]

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

[maurice]

This thing is starting to give me sleepless nights

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

[Kipper4]

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

[slacker]

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

[maurice]

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

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

[maurice]

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?

[slacker]

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

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.

- 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.

- 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.

- 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.

[maurice]

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.

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

[maurice]

polite Bump