Memory Man ?'s... yet again...

[BDuguay]

I searched for the info I need and discovered many others were interested in the same thing but not much was offered so I figured I'd try again
I have the 3 knob Memory Man (w/ boost switch) that seems to me could use a little re-calibrating. A schematic or a simple point in the right direction would certainly be appreciated.
Thanks all.
B.

[Mark Hammer]

Would it be this one?  http://www.effectsdatabase.com/model/eh/memoryman

Unfortunately, I don't have a schematic for it.  However, a couple of questions could peg down what needs attending to and how to do it.

1)  How many BBDs does it have?  Is it a single 4096-stage device or one of those issues with a fistful of SAD1024s?

2) How many trimpots on the board in total?

[BDuguay]

Yup, that's the one.
I haven't yet popped the hood on this one but I will do so tonight and report back pronto. I've got far too many pedals at home right now with the bonnet open, waiting for attention, and I'm starting to feel a tad overwhelmed. With this one, I wanted to get the schematic ball rolling first so pardon my unpreparedeness.
There's a little star studded story in the future for this pedal too.....
B.

[Mark Hammer]

Well if my assistance means that the flag-bearers of Canadian music can hold their heads a little higher, and solo with a little more confidence, then I'm in.  Keep me posted.

The dividing line will likely be the single-vs-multiple-BBD fork in the road.  Multiple BBDs in EHX pedals generally means individual bias trimpots, and maybe even individual output-balance trimpots.  Adjusting those is a bit like watching a commercial for one TV on a different TV, and trying to decide if the advertised one is a better picture or not; your tuning is hampered by the weakest link.  Happily, there are ways past it.

[BDuguay]

Here's the dirt.

3  SAD1024 chips
1  4047
2  RC4558's

Now here's where it gets weird. There are 3 trim pots on the component side of the board and 3 more trimpots tacked on to the solder side of the board. The latter 3, judging by there location on the solder side of the board,  appear to be individually connected to the 3 SAD1024's.
At this point it should also be noted that there is a 'Howard (Mick) Davis' business card taped to the bottom cover which leads me to believe we're 'not in Kansas anymore' so to speak. Also, there are a couple of caps tacked to the solder side that look too new to be original.
I am currently, and will be for some time, all ears.
B.

[alteredsounds]

If you need any pointers on this feel free to msg me, I've just repaired 2 non functional DM's both with SAD1024's and a 3rd with using a MN, learnt alot along the way lol 

[Mark Hammer]

The trimpots are going to be assigned to the BBDs, two to a chip.  One (10k) will be for setting the bias, and will have the wiper tied to pin 2 or 15, through either a fixed resistor (100k?) or through an op-amp buffer stage.  The other will be for either setting the output of the BBD or the balance between output pins (5/6 and 11/12).  Looking at the 7550 issue, it appears they used one 5k trimpot to ground on the output pins of the second half of each BBD, to set the output level (the schem labels it "gain") of that BBD.  The last SAD1024 in the sequence has the same 5k trimpot wired up between pins 5 and 6 as a balance control.

[BDuguay]

I tried earlier to reply to A.S. but I got booted.
This pedal works but just not that great. Weird distorty, artifacty repeats and so on. Without a schematic and some suggestions as to where to start, I'm kinda at a loss.
B.

[Mark Hammer]

Well that's what the trimpots are intended to prevent, so clearly your mission is now defined.

Step 1, measure the voltage at the wipers of the bias trimpots, and see if one or more are outliers.

[BDuguay]

That I can do!
Er, what voltage am I'm lookin for?