Author Topic: Bad Stone schematics (which version is correct?)  (Read 2339 times)

The Groke

Bad Stone schematics (which version is correct?)
« on: August 16, 2012, 04:51:56 PM »
Hi. I have been trying to repair my Bad Stone pedal. Mine has the C375 circuit board, which I believe is what was in the first version, but it is enclosed in the 2/3rd version case and has all of the functions of those models. I have read through every post on this pedal on this and other forums, but I'm only getting more confused. It seems that there were at least three versions of the schematic for this pedal, plus an old EH copy that looks more like a prototype than anything else.

This one (by Muzique Giles Petri) is supposed to be correct:
http://topopiccione.atspace.com/pjimages/EHBadStone.sch.gif

And these are supposed to have mistakes, mostly in regards to the pinouts of IC B, I believe:
http://topopiccione.atspace.com/pjimages/EHBadStone.sch.old1.gif
http://topopiccione.atspace.com/pjimages/EHBadStone.sch.old2.gif

My problem/issue is that my Bad Stone, which only partially works (manual sweep is fine, but noisy; rate works for about 200ms and then stops) matches the IC B pinouts on the "incorrect" schematics, not on the correct ones!!!!

At first I thought, OK, this doesn't work because the last guy was fixing it to the wrong schematic, but now I'm not so sure. On mine, the input signal, for example, goes right to a large pad which branches to a 100k resistor and then pin 3 of IC B1.  And Pin 5 of B2 links to a 3.3k resistor.

Has anyone else encountered this? Is my Bad Stone really wired up wrong, or is the schematic wrong? I know many people have built to that particular schematic, but it really seems as though my pedal is closer to the earlier versions.

Some of the .1uF caps (big tan ones marked 104) do not look original, And the auto/manual switch was originally missing with wires taped off, so I don't doubt that someone was messing with this before. but again, the big question is "what am I supposed to be restoring it to"?



Pics of my board are here. I should mention that some parts were replaced at various stages in taking these pics - which is why you will see different components in different pics. I took out the BC239 resistor and put in a 2n5088; I recapped all the electros; I put in a 4049 in place of the 4009; and I put in a new LM324:

The first four are the latest:
http://www-personal.umich.edu/~damont/BadStonePics/CurrentWiringComponents.JPG
http://www-personal.umich.edu/~damont/BadStonePics/CurrentWiringSeeThrough.JPG
http://www-personal.umich.edu/~damont/BadStonePics/CurrentWiringTracesAndWires.JPG
http://www-personal.umich.edu/~damont/BadStonePics/CurrentWiringTracesAndWires2.JPG

These are older pics of when I was reconstructing the board:
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3308.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3310.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3312.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3314.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3315.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3318.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3319.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3321.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3324.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3325.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3327.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3329.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3332.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3334.JPG
http://www-personal.umich.edu/~damont/BadStonePics/IMG_3335.JPG

These are my voltages with the current wiring (off a 9.3V regulated supply). They all seem a bit lower than those indicated in one of Barcode80's old posts:

LM324
1 1.6
2 2.7
3 2.7
4 7.7
5 1.7
6 1.7
7 4.5
8 .68mv
9 4.4
10 2.7
11 .2mv
12 2.7
13 2.5
14 6.4

4049
1 4.7
2 2.6
3 4.7
4 2.7
5 4.7
6 2.7
7 4.7
8 2.7
9 4.7
10 2.7
11 4.7
12 2.7
13 4.7
14 4.7
15 2.7
16 4.7

4558
1:  2.7   
2:  2.7     
3:  2.7     
4:  0.00   
5:  2.7
6:  2.7
7:  2.7
8:  7.7

I hope someone can answer with at least some clues about the wiring....

Thanks so much.

DT

The Groke

Re: Bad Stone schematics (which version is correct?)
« Reply #1 on: August 16, 2012, 04:58:45 PM »
Regarding what I said here:

"On mine, the input signal, for example, goes right to a large pad which branches to a 100k resistor and then pin 3 of IC B1.  And Pin 5 of B2 links to a 3.3k resistor."

I marked a little red R7 next to the 100k resistor on the second picture in my post (the see through one). You can see there the branch from the input signal to R7 and pin 3 (not pin 5 as on the "corrected" schematic.

And please note that I am not knocking anyone's hard work here (the schems and work are greatly appreciated)... the "correct version" is obviously correct for many people.. but could there be versions of this board where it is not correct????

Thanks - D

The Groke

Re: Bad Stone schematics (which version is correct?)
« Reply #2 on: August 17, 2012, 04:43:20 AM »
One more bit of info (if anyone is following this), my components/component values and board, and I believe the wiring (to the extent that the two knob matches the three knob version) seem to match this two knob version at home wrecker. You can compare my first four linked pictures above to his board/gut shots:

http://www.home-wrecker.com/badstone.html

On his board, it also looks like the input goes through the .1uF cap into pin 3 of IC B.

Is everyone out there wiring into pin 5 (as in the corrected schematic), or is there someone else wiring into pin 3 with success???  Or am I somehow totally misreading the layout on this board?

Thanks - DT

The Groke

Re: Bad Stone schematics (which version is correct?)
« Reply #3 on: August 17, 2012, 01:55:36 PM »
Ah... 4558 IC... pin 3 and 5 are both inputs... duh. OK, I should have known that. So the reversal is irrelevant. Still strange that the pin numbers were changed between schematic versions (was it because it fit on the clone board better in that configuration?). I suppose for clarity, I should just follow the second version of the schematic...