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Hey all,

Trying to build a mangler with ac128's and failing hard. Couldn't get a 20k trimmer but popped a 50k in there. Biases right to 4.5v and everything. looks like I'm all wired up proper too. plug it in and the led lights and it passes audio but the knobs do very little, no fuzz at all and the sound is akin to quiet icepicks.

nothing like functional.

any thoughts?

ZZ

Finally got on the meter today with some spare time here:

IC 1

4.74
4.75
4.74
0
9.40
4.74
4.77
4.70

IC 2

1.798
8.0
6.36
1.8
9.41
1.795
1.796
.019
1.797
7.04
1.799
1.801
0
1.795
1.795
1.219

IC 3

4.73
4.74
4.74
9.40
.001
4.74
4.74
4.74

IC 4

0
4.34
4.96
4.97
7.98
4.75
4.31
8.12

IC 5

0
4.34
4.65
4.67
7.87
2.68
4.31
8.12

IC 6

2.682
2.684
2.702
0
9.42
4.82
4.79
4.77

IC 7

.644
4.90
4.6 - 5.1 flux.
0
9.4
4.6-5.1 flux
4.90
4.89

IC 8

7.99
8.02
8.02
9.40
.001
4.73
4.74
4.74

IC 9

5.03
4.24
4.27
9.39
9.39
0
9.37
5.06
0
4.32
4.29
0
0


any thoughts?

that's exciting!

anybody?

well this is interesting ( or sad depending. )

replacement cool audio chip showed up today and i popped 'er in. Sadly now neither chip will bias and i have a really crazy screaching at the pins with no delay and nothing at the input.

both IC 4 and 5.

Help?

ZZ

anyone point me at it ?

sweet!

ZZ!

so it could have failed post boxing due to static ? i know they did not show up in an anti static bag. oh well back to the order form.

After all of the 'bean builds ive done thus far this was the first one that failed. At least it appears that the whole populated board isn't scrap.

Thanks all for the help,

Best,

ZZ

got the cool audio chips from mammoth.

Chips swapped and now I'm not able to get anything to happen on IC4 so...one bad chip. I tried all gain and bias trimmers adjustment and even wound up on their extremes. nothing anywhere.

When i replaced the chips to their previous orientation they worked as before. IC4 biased up and IC5 not able to be biased to pass delay.

So bad chip yeah? I guess it just slowly failed.

ZZ

Tried fiddling with the trimmers some more and nothing yet. R28 and R29 seem correct. Within .05 of their respective values. Im also probing on the chip at both 3 and 4. Trimmers looking good as well.

I'll have to throw it back on the bench tomorrow to recheck the soldering. would a good alternate test be to swap the chips and check again? i thought about it but also have to wait on that.

ZZ

here are the voltages per pin. Measured in Vdc.

IC4 pin voltages

1 - .002
2 - 4.69
3 - 5.94
4 - 5.96
5 - 8.11
6 - 4.68
7 - 5.75
8 - 7.85

IC5 pin voltages

1 - .002
2 - 4.69
3 - 4.47
4 - 4.46
5 - 8.12
6 - 4.68
7 - 2.852
8 - 7.86


IC5 pin 7 the problem? Bad chip? I tried biasing the whole thing a few times and no dice. thoughts?

ZZ

Finished a build of a V3205 Dirtbag deluxe a few days ago and for a bit there everything was sounding good. I was quite impressed with the quality and did prefer it over my diamond memory lane 2 (if you can believe it, the repeats blend better.)

All gravy until...

The effect doesn't do anything one day. LED lit, volume responding but no repeats and certainly no lovely lovely oscillation or feedback. Thinking maybe some of my off board wiring ( pots jacks switch ) were to blame i redid all of it taking the utmost care. Plug it back in get the probe out and what I found is this.

IC4 Pin 3 Biases in and I have repeats. I can hear some noise in the background...hiss and what not but nothing crazy.

Moving on to IC5 Pin 3 and the only thing audible is a really high pitched whistle. Upon checking Pin 7 there is signal and it sounds like a slightly lower fidelity version of IC4 Pin 3. I imagine that means that everything is cool until that point.

What's the deal? do I have a dead chip or something worse?

Thoughts?

ZZ

Wow! Beautiful!

Ordered some Darksides. Built one just this week and I love it.

is the darkside going to be discontinued?