Schematic for an original Memory Man (SAD1024 version)?

[zarathustra]

I recently acquired an old Memory Man. Pot codes say 1977. It actually looks to be in great shape, but, of course, it doesn't work. If anybody has a schematic, it would be a big help. This is the three-knob version with a boost switch, no chorus. PCB says EH1309A. There are six ICs that I can see: three SAD1024s, two 4558s, and a 4047.

I seem to have found schematics for every version except this one. None of the other schematics has the boost switch, and that's what's giving me problems. Somebody decided to pop off a few wires, and I can't for the life of me figure out where they go. 

[A.S.P.]

I`ve seen it here within the last week - just can`t find it right now.
maybe you do a search for "stephen giles"?

[Thomas P.]

If you mean the one schematic floating around here - frankly I believe it isn't quite right...

[A.S.P.]

sorry: the "search" currently doesn`t work here for me!

nevertheless I found for you what I thought would be the one:

but it isn`t it

(but it was within the last 5 days...)

[zarathustra]

Yeah, I have that one, as well as a few others, but none of them has that elusive Boost switch. Thanks for the help, though!

[boyersdad]

I also have one of the (I'm guessing from multiple peoples posts) '77 3 knobs, with boost switch.

When I got it, the switch had been removed, and hardwired into boost mode. I eventually put a stomp switch on it to switch the boost in and out. It's way to hot to have on all the time.

I have not been able to find a schematic for it anywhere, and really needed one when I first got it, as it was passing no signal (wet or dry).

I started with the delay chips, assuming them first (after checking all the wiring of course). I swapped them into a flanger I had that uses the SAD1024, and discovered that all 3 chips work.

Then, I replaced all the electrolytics. I had some clean sig and some noise now. On the right path!

Then I wrote down where all the bias trimmers were set, and started to tweak them one at a time, one side to the other, and eventually, I got some sound going. Just kept tweeking until it was all there!

Then I replaced the wiring inside with shielded wire, to cut down on the clock signal bleeding into the audio.

Now she's as good as new.

Still really wish I had the schematic for it. Maybe someday when I'm feeling brave I'll try to trace it myself...

EDIT: Oh right! The point of me posting this! I can take a picture of the inside of mine, so you can see where the boost wires originate and terminate, and maybe that will give you a hand?

[zarathustra]

Hey, thanks for the offer, but believe it or not, I managed to find the schematic! PM me with your email address, and I'll send you a copy.

By the way, did you manage to get completely rid of the clock whine on yours? That seems to be my biggest problem right now; I get whine from about 12 o'clock up on the Delay knob. I've replaced most of the electrolytics, but there are still a few old ones on there (e.g., the power supply caps). Shielded wire on the in/out jacks sounds promising. I'll have to give that a shot.

I also get a lot of grainy background noise. I know the old BBD chips probably have a lot to do with that, but I'd still like to reduce the noise, if possible. Did you have any success reducing background noise? I'm considering swapping out the 4558s for some TL072s, not sure how much difference that will make, though.

I *think* I have the trimpots pretty well set, but I've been setting them with an audio probe (no scope), so who knows, I could be way off.