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Black Swamp build thread
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8 [all]
Author Black Swamp build thread
Disconnect the power to all PCBs that you aren't working on.
Don't replace chips yet,those are really easy to test.
The top of the SOLO board is where the power header is.

With the power supply off and the power wire to this PCB connected and the SOLO switch in the down position there should be continuity between PAD S at the top and 0v. If the 0v connection on the SOLO switch goes to a PCB that PCB will also need to have the power cable attached. With the switch up there should be continuity between the upper and lower S pads.
Turn switch off (down).
Now apply power.
You should have 5v at the lower S pad.
You should have -12 volts at pin 4 on all chips. A spot check will do.
You should have +12v on pin 13 on all chips.
You should have continuity between pin 5 and 0v on all chips.
The right side of R1 should be at the expected voltage, 5v with link for R1 and the calculated voltage based on your choice for R1 & R2.
Test the DG202
To test the DG202 we need to first make sure the CGS86 is working.
Remove power from the solo board,connect power to both the touch pad boards.
Always turn off your power supply when attaching/detaching power cables.
As you press each touch pad the GATE PAD for each section should go high and stay high while your finger is on the touch pad.
Plug in the SOLO board. Turn SOLO switch on. Remember if the 0v for the solo switch goes to a PCB that PCB needs to be plugged in also.
For each section when you press the touch pad PAD G should be high (around 5v) and PAD D should have the same voltage as the end of R1.
Test the DG201
With the solo switch off there should be continuity between the following pairs of pins: 2&3,6&7,10&11,and 14&15.
With your finger on the touchpad for the section you are testing PAD P should be high.
There should not be continuity with the SOLO switch on,and PAD P should be low when touching the corresponding touchpad.
I dont have enough time to completely write this up but will followup later, I'm between coming home from work and going for turkey dinner.

Right now this is mostly how I'm feeling not this shit again

Following your last set of instructions I didn't have any five volts and started poking around from the power header and still cant believe it but found I hadn't put in the ferrite beads d'oh! d'oh! d'oh!

Of course things seem much better now, but this is where time has limited me and I need to test further. But at a glance I think the solo mode may be close to working. With the switch in the down position Row D CV is part of the Row D output and the touch pads will move and hold where they are touched. With the solo switch in the up position it seems like the CV is removed from the Row D output and the touch pads let me touch them but continue shuffling along with the clock
The row D out will only have voltage when a pad is being touched in solo mode.
If not then check if there is continuity from the SOLO board PAD D to the CW lug of the row D pot for that stage.
Quick update before heading off to work; I'm thinking I'm good now in solo mode, I didn't realize that in solo mode the Row D CV is generated by the touch pads but is still subject to the knob position. I had them all turned down hihi So looks good now thumbs up
I think I'm good to move on and have been trying to trouble shoot the vertical sequencer. There seems to be two issue, the first is that it never enters Row D. And the other is when set for 3-step, it doesn't reset directly from Row C back to Row A. There seems to be one clock cycle missing. The Row C led will go out, but wont toggle to Row A for one more clock cycle (16 steps on the horizontal).

Observations so far:

I can only see gate outputs from P1 - P3 & P8, I have also confirmed this with the outputs off the 4051 (nothing on Pins 1, 2, 5 & 12)

There seems to 1v constantly sitting on RSE, although the reset switch works

Changed all chips except the TL072

I have checked the switch wiring and all seems to be in place there. I have run continuity checks with the power off and have found:

switch in 2 step, continuity from RSS to P3
switch in 3 step, continuity from RSS to P4
switch in 4 step, continuity from RSS to P5
I have struggled with this circuit more than once.
The switch wiring seems correct based on your continuity checks.
But if there is no gate output on P4 or P5 I wouldn't expect it to reset.
Read my post way above this about finding a fix for this, and if there are no wiring issues it might be worth contacting Ken on his Yahoo group and run this past him also.
I'm a bit lost, but if the vertical sequencing is handled by a CGS28 sequential switch, do not use a TL074 in that circuit. I know Jon has had success with some TL074s (and not with others -- alarm bells ring), but the circuit as designed is taking the input common mode far too close to the power rail and the TL074 exhibits phase reversal.

All my vertical sequencing issues on the TPS, which was done with a CGS28 in my case, were resolved when I replaced the TL074 with LM324 which can handle low inout voltage without issue.
Thanks for the tip.
I've on 3 different occasions had this circuit not work with a TLO74 from Texas Instruments but work fine with the STMicro version.
Yes, I remember reading that somewhere but I couldn't find it and I couldn't remember which manufacturer was the working one. Ken is no fool so presumably it worked for him too. But the TL074 is being used way out of spec in this circuit and its just easier to go back to the 324.
The random wasn't working but after visiting the schematic I realized the the led's are required d'oh! easy fix and is working now.

So it looks like I the vertical sequencer may be the last issue for this build. I tried an LM324 and it didn't have any extra magic, same issues. I tried with and without the 4.7M and voltage divider but still nothing. I didn't really have any issues with the TPS when I built it and its using the same CGS28 for the vertical.
You could try swapping the chips from the working one to the non working one.
In troubleshooting I noticed by accident that if I touched the 4051 pins it started working. Playing with this more I isolated it to the last two pins of each row. After a bit of experimenting and 100nf across pins 7&8 causes it to work. I dont know how or why but at this point I'm not even sure I care.

Everything seems to be working. nanners nanners nanners nanners

And I got to say thank you so much for the amazing & detailed level of support. we're not worthy we're not worthy we're not worthy we're not worthy

Next issue, craming it into a box, as it stands it isn't even close to fitting. There may be a ton of rework to shorten or move stuff to help it along. Dead Banana If only the boxes came 5" deep hihi
Congratulations. No problem with the troubleshooting. Now get it in the boat without breaking any wires
I came to the quick realisation that this would never fit i to a 3" deep boat with the way i had built it. There was of course only one solution, build my own deeper boat
Mr. Green

Thanks again Jon for helping bring another one of these to life. Ive now got two down and one to go nanners
That looks fantastic
I would love to see some videos of one of these systems. After all this time, I've decided I'm going to build mine after I get my DIY easel done.
I'll be here to help.
I'll be here to help.
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