Moodring issues...

[cajone5]

Got this wired up twice now.  Tried the buffered version and the LED always stayed lit.  So I unwired and tried the true bypass version.  I kept the extra wires from the switch and taped over them so they are not able to contact anything else.  For the "byp" wires, I twisted them, soldered and taped over them so I can undo it if I have to.

Anyway, I am getting a bypassed signal but no effect.  It's a bit of a mess at the point but photos are included below.











Voltage on IC1...

1 - 1.36
2 - 1.31
3 - 0.88
4 - 0
5 - 0.88
6 - 1.37
7 - 1.37
8 - 9.16

IC2 (regulator)
1 - 4.92
2 - 0
3 - 9.16

IC3
1 - 4.92
2 - 2.44
3 - 0
4 - 0
5 - 2.64
6 - 2.39
7 - 0.78
8 - 0.79
9 - 2.44
10 - 2.44
11 - 2.44
12 - 2.44
13 - 2.44
14 - 2.44
15 - 2.44
16 - 2.44

IC4
1 - 1.38
2 - 1.38
3 - 1.04
4 - 0
5 - 1.04
6 - 1.38
7 - 1.38
8 - 9.16

The PT2399 and regulator look fine.  The TL072's do not.  Anyone have any thoughts?

I almost forgot to add that I added a modulation board using the Grind Customs layout (on vero) as recommended in a modulated moodring build thread.  I used the layout below...



In addition, for replacements there...
-- Wired shape sw2 to shape sw3 (so no switch)
-- Removed 1k in parallel with LED and 2kB depth pot and 250kC for rate
-- Used On/On spdt for modulation switch and did not include ground (left open terminal) to just have an on/off style toggle

More info here... http://www.madbeanpedals.com/forum/index.php?topic=23642.0 ... on the modulation add-on

I hope this all makes sense...

[cajone5]

I just realized I forgot to post voltages on the brick... will add those tonight!

[madbean]

Comparing your voltages to the ones in the doc you can see the Vb supply is way off. It should be about 4.5v, and yours is reading 1.3v pretty consistently. So, you need to re-check R35, R36 and C36 to see if they are correct values. Then look at all the areas connected to Vb on the circuit and ensure that there are no solder bridges, etc.

One shortcut is to first remove IC1 and IC4 from there sockets. Then check the Vb voltage in the bare socket (say pin3 or pin5 of IC1). If you suddenly ready 4.5 or so with either IC removed then the problem is likely one of those ICs.

[cajone5]

Pilulled ICs and verified the voltage. Still and issue.

Checked C36 - 100u
Checked R36 - 10k
Checked R35 - 100k <------ supposed to be 10k

Replaced R35 and it works. It doesn't sound that great right now although I haven't done much to set the internal trimmer. Still need to verify that the tone, predelay and feedback controls are working well (mix is definitely working as is the dry kill) but i didn't have time to properly test it last night.

Also the modulation isn't working so I need to review that wiring but it's getting thee. Not sure if it's an error or an issue with the Vactrol. I'll report back when I can try to debug.

Thanks Madbean!  Wish I could intuit these errors like you can. You're the man!

[Boba7]

Glad it's starting to work. Hope you find the problem with the modulation board! I used a simple tayda LDR with a red led if I remember correctly.

[cajone5]

I am using a VCTL3 at the moment. I'll measure voltage on the LED and resistance on the photoreaistor side while tweaking the knobs to see if that's functioning right.

[cajone5]

It's working now. I added a parallel resistor on R31 to bring it down to about 11k and tried it again. Sounds good. Also tweaked the trimmer and now really digging the pedal.  . It's still a little tough to get my head around all the controls and how they interact but I think it's a keeper.

Thanks for all the great input and help!

[Boba7]

Yeah all the controls are quite interactive!

The tone control influences the amount of feedback.
The predelay influences the modulation depth (below 9 o'clock on the predelay pot, there's not enough time to modulate, so no modulation)
The modulation depth influences the amount of feedback (when on, you need to crank the feedback pot)

The only controls that don't seem to be interactive with others are depth (just the overall wet volume) and modulation rate.

Mine is definitely a keeper!