any Deluxe Memory Man experts here?

[MarkB]

I just scored a vintage Memory Man and a Deluxe Memory Man for pretty cheap..  

The Memory Man just needs a new Echo/Chorus switch and some cleanup - otherwise, it works (and sounds) amazing.

The DMM is getting signal, but not passing any (yet) - and I'll be debugging it later on.  (I'm hoping it's not the chip, but it could be - or it could be a loose wire.. please be a loose wire).

Which chip does the DMM use for delay?  is it an SAD1024?
"-)

[jimbob]

Puretubemight be able to help u here--I have the Del Mem Man and had to replace both switches--He guessed my problm and was right.

Good luck--Ps-chk the schem and schem links above ..there are some Mem Man info in there was well as a few mods ect..

[puretube]

- september - stop - holiday -stop - delay - stop -

[MarkB]

Well - I'll start tracing it with an audio probe..
now that I look at the schematic - it's not an SAD1024.. but an MN3005 (not sure that's any better).

I'm still holding out for a bad wire.
"-)

[MarkB]

ummm... how many versions of this pedal were there?

the schematic I found doesn't resemble what I have here (as far as controls).

First off - it has 4 SAD1024's in it... not MN3005 like the schematic here shows.

Mine has the blue/red printing on it.  Has an input, a direct out and an echo out.

Controls:  Level, Blend, Feedback, Delay - and a 'Squelch' switch.

"-)

[marrstians]

i had a couple of broken dmm's... the first thing to do is make sure your sad1024's are working... if they are it's usually a bad cap or crappy wire... if the bbd is bad then you've got a lot more work to do... i got two dead ones and all the chips were fine in them, i don't know if that makes you feel any better but it did for me... i have the schem for the one with sad1024s but it's on real paper and i don't have a scanner or i'd share it with you....

[MarkB]

Is there any easy way to test that the SAD1024's are OK?

Each chip has 2 trimpots - and I don't have a scope (though I can probably get my hands on one) to re-tune them.   They look visibly ok - no burn marks, etc - which is a start, I guess.  They're all socketed, too.

I've visually inspected it - nothing obvious as far as wires, traces, etc.  Will pull out the magnifying glass later on.

If anyone else has this schematic - PLEASE let me know..
or Marrstians - if you want me to scan yours, I'd be happy to do so (not sure where you live - but mail is always an option).

I hope I can get this thing running.. they're supposed to be great.
"-)

[marrstians]

on the first broken mm i had, i took the bbds out and sent them to someone else to test in a working unit that uses sad1024's... at that time i didn't have anything that i could switch them out and see if they were good... the second one i used an audio probe... look for the data sheet for it, i think i saw one at geo... check the pinout and make sure you're getting audio up untill the sad1024, the far one to the right by the 4xxx ic is first... i check the input pins with the audio probe than the outputs... if you're getting some weird noises from the outputs then they're usually working... keep moving to the left and see if they're all about the same... if you can't figure it out you could always mail me your ic's and i could test them out for you as now i have a working pedal that uses that bbd... if you get completly frustrated, i know a guy that fixes those for a living, he only charged $30 to fix it, that's if your ic's are good...

[MarkB]

well - let me crack open my working Memory Man and see what that uses.. I think the units are from the same time period (78ish)

[edit]
nope - MN3005 in the Memory Man..  I may have to pick up that DEM that he had at the shop.. you know, for testing purposes.

"-)

[MarkB]

the far one to the right by the 4xxx ic is first... i check the input pins with the audio probe than the outputs... if you're getting some weird noises from the outputs then they're usually working... keep moving to the left and see if they're all about the same

Stupid question... when you say 'far right' - you mean when looking at the component side of the board, right?  not the trace side.

just want to make sure.
"-)

[marrstians]

should be the one closest to the pot and 4xxx chip...

[jplaudio]

Is there any easy way to test that the SAD1024's are OK?

Each chip has 2 trimpots - and I don't have a scope (though I can probably get my hands on one) to re-tune them.   They look visibly ok - no burn marks, etc - which is a start, I guess.  They're all socketed, too.

I've visually inspected it - nothing obvious as far as wires, traces, etc.  Will pull out the magnifying glass later on.

If anyone else has this schematic - PLEASE let me know..
or Marrstians - if you want me to scan yours, I'd be happy to do so (not sure where you live - but mail is always an option).

I hope I can get this thing running.. they're supposed to be great.
"-)

Schematic:

3 pages
http://home.twcny.rr.com/jplaudio/eh7550.JPG
http://home.twcny.rr.com/jplaudio/eh7550pg2.JPG
http://home.twcny.rr.com/jplaudio/eh7550pg3.JPG

[MarkB]

Thanks!
THat looks like it - but the numbers don't match up - mine is labeled EH1307.. I think the 7550 is a later model, but it should give me a better idea than the MN3005 version.
"-)

[soundcollage]

I just fixed one of these for my buddy. You are going to need a scope. I fiddled around forever without one and was not able to fix it, once I got a scope the process is much easier. Unless all of the 10k trimmers are all aligned properly --no sound. The unit I fixed had several 4.7uf caps that were bad, so I suggest checking those as well. If you had to do it without a scope use an audio probe on the output of the first delay chip (next to the clock chip)and adjust the 10k trim until a signal is heard. The other trimpot below  the chip is a gain adjustment set this from the input of the next delay chip. move on through all four. Good luck as it is diffucult to get a clean signal to pass even with a scope as the trimmers are finicky

[MarkB]

don't have a scope (yet) - may be a good excuse to buy one and learn how to use it.

I'll mark the current trimmer locations and try playing with them using an audio probe and a test tone.

If I can get this bad boy working again - I'll be thrilled.
"-)