Hello! My Zendrive has no drive!

[Kipper4]

Are you waiting for a particular cap?

[Kipper4]

Something else I just noticed was that the LED lights weather or not there are cables on the jacks.

I assume from this you used a switching jack or TRS for the input.
Is this so?

It depends on input jack switching and indeed your 3pdt wiring.

[thermionix]

In my builds now I do it so that with a battery it needs a cable in the input jack to turn on, but with a wall wart it doesn't.  Commercial pedals (and kits) vary, with some you always need a cable in the input.

[SirHugo]

I think it's just a normal enclosed switch craft jack with just one sleeve and tip. It may be the wiring on the switch. Yeah I'm waiting on a cap to make the probe.

[Kipper4]

You can use a 100nf ceramic cap maybe even try 47nf for the probe.

[SirHugo]

Ahhh 47k works?! That's great I've been hard pressed to canabalize a 100u from anything but a 47 im sure I have. Thanks!

[thermionix]

47k is a resistor.  Anything near 47n will work.  You don't want teeny tiny, you don't need huge.

[SirHugo]

Ok after a bit of a break from the zen. I'm taking it off the shelf and tinkering again, I haven't changed anything yet but I have my probe set up now with a look to check it. I am however a bit bewildered as to what I should be looking for, some points are loud some are quite and some seem to break up and almost sound pixilated for lack of a better word. I know I need to trace the schematic, but I'm unsure what a red flag might be if I come across it short of no signal what so ever.
Thanks a head of time for your help!
JHK

[Kipper4]

Chill out we will do our best to get you there Sir.
Some bit of the circuit will sound different to others. Level,fuzz....... As long as you have signal  is enough for now.

So looking at the aion docs.

Ac (guitar) Signal goes in the input.
cover the basic.

Through C1 to the + (aka Non inverting) op amp input.
out of the op amp to R4 Through the tone pot (might be some signal lose here at the node of Tone lug3,C4.)
Reason being it's what we call an RC filter.

> pin5 (non Inverting) op amp input. Check this too.
check its output pin7.

Through the C5 output cap.
I suspect you will have lost signal by now.

Make sense?
Probe away.

I'll be back in the morning. Smoke me one.

[SirHugo]

Thanks so much kipper! I appreciate it! I'll scope it out, and post my findings. One thing I have noticed just probing about is that one of my BAT41 and my Germanium diode both sound like a dying battery, not sure if that's normal or not, I suspect not but I'm still quite novice at this as you can tell. Happy to say I built a Vertex steel string clone without incident, so I'm happy about that. Hopefully the probe will illuminate the Zens malfunction.
JHK

[chromesphere]

Hi SirHugo,

As most others have suggested I would also recommend checking over your soldering, I can see a couple of solder joints on the 3pdt that look like they are in very close proximity.  I would check over all of your offboard wiring for errrors.

On the pcb a few things you should try:
- Look for solder bridges here as well (bottomside of pcb)
- Try replacing the AD712 with something pin compatible, perhaps a TL072, to rule out the IC as the problem.
- Check values of the resistors, caps, etc

I would suspect a soldering error though and encourage you to check over your soldering an reflow anything that looks suspicious, make sure there is adequate spacing, etc.

Hope it helps and good luck!
Paul

[SirHugo]

Ok Kipper here's what I found
Input (loud) obviously
I'm on switch (quite)
I'm on board (no sound)
C1 (medium)
R4 (medium)
Tone (all lugs medium)
C4 (medium)
Pin 5 (loud/distorted)
Pin 7 (no sound)
C5 (quiet)
Volume (lug 1 no sound/Lug 2 & 3 quiet)
Out on board (quiet)
Out on switch (loud)
Out on jack (Loud)

So the other oddity I'm not sure if it's worth mentioning is that
D2 - loud + dying battery
D3 - dying battery +dying battery
D4 - no sound + dying battery
Not sure if that's normal

Paul,
So far I have triple checked the components
Relowed twice
I've got a back up IC which offers no change that I can tell
So far as I can see there are no bridges
I've also Metered the whole board twice with no obvious issue
The 3pdt has been since cleaned up since the intial photo post
Thanks for the heads up though man, I scoped out your site and really dig it
I'm ealecially interested in the buffer and I'm loving the dial decals you've made.

[Kipper4]

There we go. Pin5 good pin7 not.
Check pins 6&7 Are connected together.

[SirHugo]

Alright I checked it out, but I don't see any connection between 6&7 here's a picture for reference.

[Kipper4]

I can't tell from the pictures. The trace is probably internal or some such.
However you can check 6&7 are connected with your meter on continuity test mode.
Probe on 6 probe on 7..

[SirHugo]

Tried the continuity meter but it's not reading anything on anything lol, it's a cheapo so it dosnt create a tone even when it works it's just reading "OL" and when it dose work it reads a 3 - 4 digit number but only seems to get a read off of the switch lugs. The meter works on every other setting though so I'm not sure what the deal is with the continuity setting.

[SirHugo]

Also I made a mistake on the list Obove,
Pin 3 on the ic is loud/distorted
Pin 5 is quite quiet
No signal on pins 6 + 7
No signal on pins 1 + 8
Pin 2 is about medium volume

[Kipper4]

I found this Seymour Duncan forum.

"I posted this a while ago to help someone learn about continuity. I'm just looking for others to add their thoughts/opinions, etc. as I don't think that I write all that clearly compared to others in the forum.


"Not all meters have a buzzer/light for continuity.

If the meter is set to around 20 Kohm resistance and the test probes are not touching anything, the readout should be "0" or ".0L" .....this means that if you get this reading there is NO connection between the parts...that is, there is a loss of CONTINUITY of electrical circuit. Some meters have a continuity beeper/buzzer that will sound when there IS continuity (showing that the circuit is therefore intact) or conducting when two electrically joined parts are being tested.
If you get a small resistance reading..the circuit is intact and you are reading the resistance between the two points being tested.

CONTINUITY is one of the most useful (and simple) things you can learn to do with your meter IMHO, especially for wiring guitar circuits.

You can make a simple continuity tester with a set of probes, battery and a buzzer. Connect everything in series with the "break" in the circuit being the probes (just like a switch). When you touch the probes it buzzes...if you touch the ground at the jack and the the ground on the pot (or a ground anywhere else) it will buzz, showing that you have continuity with the grounds. A buzzer is better than a light because you don't have to look away from your testing to see if the light is on/off.

You can check your electrical connections between any two points this way.

Hope this helps."


Maybe try the ohm setting thing.

If the connection is bad you could breach the pins6,7 and test the circuit again for audio.

Let's see.

[Kipper4]

Also I made a mistake on the list Obove,
Pin 3 on the ic is loud/distorted
(that's your guitar straight.)

Pin 5 is quite quiet

No signal on pins 6 + 7

No signal on pins 1 + 8 ( pin 1 is the op amps output you should get a signal here. All of the circuits gain happens there. The resistances in the negative feedback network determine the gain.
(AD712 is a dual op amp package. One is made up of pin 3,2,1 the other 5,6,7.)

(Pin8 is the +9v rail. I'd expect to hear dc here not our guitar signal. DC powers the componants. AC is our guitar.) Stop me if I'm "teaching my grandma to suck eggs"


Pin 2 is about medium volume

I'll quit while I'm ahead.
I'd look at the stuff around the negative feedback loop.
Have you a magnifier and light Sir?

[SirHugo]

Yes I do! And thanks btw for the continuity post that was incredibly helpful, btw pin 6 and 7 together ready about 1130 or so, so I guess they're connected.