EHX - Memory Man - Solid State Echo/ Chorus With Boost Input

Scruffie · Post by **Scruffie** » 30 Dec 2010, 20:26

Just Got this in the Post Today from Member Slor, not too much about on this one so I got some gut shots for it.

The Schematic floating around for this one calls it the 'Economy Memory Man' Due to it's lack of Companding probably, haven't had a chance to plug it in myself yet (Need to grab a U.S. to U.K. Adapter).

I Notice my one seems to have Purple Writing as opposed to the pictures i've seen of these which all seemed to have Blue

Anyway...

Bit of work done to it at first glance, new trimmers, new jacks, new 4047 chip and it's missing the knobs but I plan to order some clones, replace the electrolytic & tantalums (It does apparently have a few issues, not just doing that for fun) and get some original skeleton style trimmers to get it back close to original spec and running nicely.

Anyone got any good tips for cleaning up the enclosure? Or should I just take it as is, not in too bad condition but a bit of rusty scratching, was thinking a bit of wet and dry and buffing would be okay but best to check first.

Graemeys Demo, Excellent as always -

And the Guts:-
(Have Plenty More if Requested)

Dirk_Hendrik · Post by **Dirk_Hendrik** » 30 Dec 2010, 22:15

Scruffie wrote: Anyone got any good tips for cleaning up the enclosure?

No alcohol!!!! Been there, got burned. EHX prints dissolve in alcohol. (More general, ;when attempting to remove old duck/gaffa tape from pedals use standard oil to soften the dried out glue)

Start off with water and some standard kitchen cleaner (The stuff you clean (you do don't you?) your kitchen floor with) and a toothbrush.

Getting that "like new" shine back?
Very, very moderate amounts of carpolish and wax do miracles.

lolbou · Post by **lolbou** » 30 Dec 2010, 22:29

I use WD40 for old glue and dirt.

Scruffie wrote:get some original skeleton style trimmers

My '79 DEM had both Pihers black ones and skeletons in it. I would go for Pihers instead if I were you.

Scruffie · Post by **Scruffie** » 30 Dec 2010, 23:09

lolbou wrote:I use WD40 for old glue and dirt.

Scruffie wrote:get some original skeleton style trimmers
My '79 DEM had both Pihers black ones and skeletons in it. I would go for Pihers instead if I were you.

Oh yeah, I forgot i'd seen them with Pihers in the past, I will use them, cheers lobou.

Dirk_Hendrik wrote: No alcohol!!!!

Thought you were ruining my New Years Eve there!

Been there, got burned. EHX prints dissolve in alcohol. (More general, ;when attempting to remove old duck/gaffa tape from pedals use standard oil to soften the dried out glue)

Start off with water and some standard kitchen cleaner (The stuff you clean (you do don't you?) your kitchen floor with) and a toothbrush.

Getting that "like new" shine back?
Very, very moderate amounts of carpolish and wax do miracles.

Yeah I used some of that kitchen cleaner stuff on it already (I do indeed clean my kitchen, fully trained in Food Standards)... regretting not checking here first though cause I could of just as easily use White Spirits and be sobbing right now, thankfully that's not the case.

I was going to try and avoid polishing the front anyway just in case but still, just in case... anyone tried toothpaste? I tend to use that for polishing things as it's cheap and I always have it on hand but I guess that could strip it too, i'll have to be careful...

marshmellow · Post by **marshmellow** » 28 Feb 2012, 18:33

Just got this one back from a friend who had it for a few years borrowed from me. It hums badly, distorts, looow treble, really muddy. But it still produces some kind of echo, so the MN3005 is still fine I guess. The transformer is completely loose, normally they are kept with a bracket to the side of the enclosure. At some point it was hotglued but that didn't stand the test of time of course.

So, first stop power supply. And probably replace most of the wiring, looks like it's going to fall apart any time soon.

Anyway, here's some guts

.

theehman · Post by **theehman** » 28 Feb 2012, 19:00

check the solder joints on the filter caps.

DJGlukBH · Post by **DJGlukBH** » 22 Oct 2012, 12:27

Sorry for necroposting

Got this pedal cheap on Ebay - filter caps'es solder joints are weak. All one gonna replace them.

Will post a reply here on results.

ED5150 · Post by **ED5150** » 27 Oct 2012, 01:18

Anyone knows where i can get the NE5554N for a resonable price? Or anyone knows an equivalent to it?

theehman · Post by **theehman** » 27 Oct 2012, 02:44

ED5150 wrote:Anyone knows where i can get the NE5554N for a resonable price? Or anyone knows an equivalent to it?

Just replace it with a couple of 3-terminal voltage regulators.

ED5150 · Post by **ED5150** » 27 Oct 2012, 04:31

theehman wrote:
ED5150 wrote:Anyone knows where i can get the NE5554N for a resonable price? Or anyone knows an equivalent to it?
Just replace it with a couple of 3-terminal voltage regulators.

Thanks for your answer, but could you tell me what regulator (part number) and which way?

marshmellow · Post by **marshmellow** » 29 Oct 2012, 17:32

7812 and 7912. The lower current versions 78L12 and 79L12 should be sufficient. Get the proper pin assignment from the datasheets, they're different.

7812:
input -> pin 1 NE5554N
ground -> pin 3 / ground
output -> pin 14

7912:
input -> pin 4
ground -> pin 3 / ground
output -> pin 11

Also add a 100n ceramic capacitor from each output to ground.

ED5150 · Post by **ED5150** » 29 Oct 2012, 22:20

marshmellow wrote:7812 and 7912. The lower current versions 78L12 and 79L12 should be sufficient. Get the proper pin assignment from the datasheets, they're different.

7812:
input -> pin 1 NE5554N
ground -> pin 3 / ground
output -> pin 14

7912:
input -> pin 4
ground -> pin 3 / ground
output -> pin 11

Also add a 100n ceramic capacitor from each output to ground.

Thanks a lot. I'm gonna try it.

Bernardduur · Post by **Bernardduur** » 30 Oct 2012, 08:49

All this talk and no schematic

Maybe this?

Scruffie · Post by **Scruffie** » 30 Oct 2012, 10:57

Bernardduur wrote:All this talk and no schematic

Maybe this?

That's the right schematic alright, thought i'd posted it for some reason but I just seem to mention it in the first post.

As can be seen, you want 7815 regulators, not 12.

Govmnt_Lacky · Post by **Govmnt_Lacky** » 30 Oct 2012, 12:10

Are those IMMENSE power filtering electros really needed for this circuit? Could those be cut down to a nice 220uF or even 100uFs?

ED5150 · Post by **ED5150** » 04 Aug 2013, 01:05

What´s the best substitutes for the transformer and bridge retctifier for the memory man? I'm planning to use a 15V transformer and the W02M bridge rectifier, is that OK?

ED5150 · Post by **ED5150** » 20 Aug 2013, 18:19

ED5150 wrote:What´s the best substitutes for the transformer and bridge retctifier for the memory man? I'm planning to use a 15V transformer and the W02M bridge rectifier, is that OK?

Please anyone?

blackbunny · Post by **blackbunny** » 21 Aug 2013, 00:31

The transformer secondary should be 15-0-15vac (which is the same as 30vac centre tapped) or 2 x 15v secondary taps, and a WO2 rectifier bridge will be fine.

ED5150 · Post by **ED5150** » 21 Aug 2013, 02:20

blackbunny wrote:The transformer secondary should be 15-0-15vac (which is the same as 30vac centre tapped) or 2 x 15v secondary taps, and a WO2 rectifier bridge will be fine.

Is that the way you connect the transformer?

blackbunny · Post by **blackbunny** » 21 Aug 2013, 05:41

Yes, that's it exactly. Of course, the primary side will be the correct mains voltage for your country or area.