Looking for schemo for MXR DDL

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AnalogPackrat

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Mine died a while back and I'd like to attempt to revive it. This is the older 2U model #113 from circa 1980, not the later 1U unit. Anyone have this schemo? I found one place that will sell them, but free is better :grin:

This thing would be a b*tch to trace as it has a large board plus 4 daughter boards plus a memory board (with slots for more if I could clone the one I have). It's mixed analog (lots of 4558s if I recall correctly), TTL, and CMOS plus long obsolete static RAM just to make it more interesting. Any help would be appreciated. I really liked using this for guitar even though it was fairly hissy.

Analog Packrat
 
How did it stop working?

Do you have the right voltages I would gues 5V DC for the ram etc. What number is on the rams?
 
http://hammer.ampage.org/

go to page 8

Should be an easy fix if you have a scope, standard digital logic.

Check the power supplys first. Look at the electros to see if they are expanded or leaking or if the heatshrink is "pulling back"
 
Thanks Gus! It stopped working after we had a power outage (it was on and plugged in when the power went out and when it came back up). Probably a surge on the line. Now it passes no audio and makes more noise than it used to when idle (bacon fying along with the hiss).

I don't have my lab set up at the moment (house remodel in progress), so I can't really dig in just yet. I wanted to have the schemo on hand. I hope it's something simple because this unit is tightly packed with daughter boards making it really tough to get probes on everything while it's running.

Last time I had it open I didn't even have my meter handy. Nothing looked obviously smoked. I'll start with the PS.

Thanks again,
Analog Packrat
 
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