small stone confusion

[oczad]

I have this very old EH small stone phaser that worked fine, but it seems someone has rewired it a bit. A couple wires came loose and when i went to find a schematic, every one i found shows it with a DPDT switch. Yet this one has a SPDT switch. (4 contacts) Was there an older one that had this switch, and if so does anyone know of a schematic with it so i can determine where the wires go? Thanks.

[Mark Hammer]

How many CA3094 chips does it have, 5 or 6? (Note: These may be labelled EH-1048)  That will give some clues as to where the wires go.

[oczad]

6

[oczad]

Ok, i was wrong about the switch. I was looking at the color switch. However, i'm still having a problem finding the effect out because the component values the schematic shows don't all exist and the traces seem different. For example, there IS a 10 UF, but it doesn't connect directly to one of the transistors as the schematic shows. Also there are resistor values shown that don't even exist on this unit. So when i try to trace it to the output i can't because the values i'm seeing in the path to the output don't exist. Does anone know of another schematic other than the "J" verson i find everywhere?

[Mark Hammer]

Googled around for a bit and all I could find was the Issue J schematic.  I have a copy of the schematic of your pedal at home,  I'll see if I can dredge it up tonight.  No promises, though.  I have a school meeting to attend this evening.  You may need to wait a day or two.

[oczad]

Thanks. You think it's different from the J? If so i'd love to see it whenever you can get to it...no hurry.

[analogguru]

While you are sitting and waiting for a better day, maybe you like to have a look at this:
http://analogguru.an.funpic.de/pictures/EH_SmallStone_75_c.gif

Good luck !
analogguru

[Mark Hammer]

Thanks, AG.  You saved me some work, and saved oczad some waiting.

Yep, that's the one.  The output of the pedal can be identified by looking for a 270k (red-purple-yellow) resistor.  Since there are two of them on the board, you'll want the one that is tied to a .0068uf (6n8, 6800p) cap on one side and a .1uf cap on the other.  The junction of the 270k and .1uf cap is your output.

[puretube]

yes, especially the LFO is different;
got an opened up box of exactly that model laying around somewhere, since~27 years now - when I find it, I`ll take a pic...

[puretube]

obsolete post...

[oczad]

Thanks !!! I appriciate the trouble you are all going to. Ok, now i need to figure out why it doesn't work when it did before all this. I cannot get a good view of whats going on with the switch because the sch. is a bit hard to read. But using common sense i have the switch's common going to the output jack and one side going to the input jack hot, and the other to the place on the board  i now see at the 27k/.1UF junction. However, unless i have that wrong there must be another problem because i get output only when the switch is bypassed. No sound when the phase is on.

[analogguru]

@puretube

The copyrights are a gift for you, cause you were so lucky to find it  
You found something, what even google couldn´t find.

analogguru

[Mark Hammer]

yes, especially the LFO is different;
got an opened up box of exactly that model laying around somewhere, since~27 years now - when I find it, I`ll take a pic...

Same LFO as the Ross, for those who are interested.  Note the electrolytic cap at the point where the LFO feeds the CA3094s.  That's a MAGIC part.  Makes for vast improvement in fast speeds by reshaping the LFO waveform as things get faster.  Stick one on your Ross and magic things happen.

[puretube]

oczad: tomorrow I`ll go down in the vaults, and take some pictures of exactly the same as yours original SmallStone pedal issue, so you can see all wires, their colors, and the pads/switches and pots they ought to be soldered to.

No need to further look into the original 1.7MB David %^&*erell`s .pdf schemo... 

[puretube]

Note the electrolytic cap

: Tantalum! 

[oczad]

Puretube, you are indeed a fine gentleman.....or as i'd be saying if i were younger, a good dude.  Thank you very much. See, this isn't my phaser. It's a friend's who asked me to fix it for him. And it's turned out to be a nightmare for me thanks to the loose wires and tangled mess it is. I like to help out friends, but if this were mine i'd probably toss it just to be done with this PITA. So your help is greatly appriciated, as i don't have the time to spend hours trying to fix a stinkin' pedal.