EHX - Memory Man 1978/79 Restoration (3 Knob Version EH1309B)

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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GSoave
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Posts: 1
Joined: 04 Jan 2013, 21:17
my favorite amplifier: Orange OR100
Location: Brazil
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Post by GSoave »

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I've found this beauty laying around forgotten in an electronics shop, it may have been untouched probably since the 80s. It's an EHX Memory Man Solid State Echo/Analog Delay Line EH1309B which was made probably around 1979.
Unfortunately, the previous owner had the brilliant idea to add a tone control to the pedal and a LED opening two extra holes in the enclosure. I decided to buy it and restore it to be as close as possible to the original. I've opened it up to see if there were any changes on the PCB. I was most worried about the BBD chips since it's almost impossible to find them in Brazil. Fortunately, the BBDs are the original ones with "Philippines" written underneath them. The OP-Amps have been changed and socketed. Two potentiometers are dated 1979 and one of them is 1978.
I don't know why and the guy couldn't tell why he added a voltage regulator underneath the PCB. It's a pretty old Brazilian regulator and I couldn't find any information online, therefore I assume it's a 15V regulator since it was soldered on the 15V power traces. I couldn't test the regulator because one of its legs is broken. The transformer is too rusty, so I decided not to plug it into the outlet fearing it would blow up or damage the pedal. There's a Boost switch which is a DPDT switch and it's working only in one position. Here are some pictures of the pedal I've bought and a picture of another unit I found on the internet with its schematic as well.
I've cleaned the PCB with isopropyl alcohol and I'm going to replace all the old electrolytics, rusty jacks, and rusty power transformer with new ones. I'm not sure if I should replace the other capacitors, you tell me. I'm not a big fan of those stamped sockets, so I guess I'll replace them as well. The rest of the components looks good to me. I still don't know what to do to restore the enclosure, besides the additional holes, it's very rusty and it has even a telephone number scratched in the paint.

I would like to know if there's a way to test if the ICs are working or not, does anyone have an idea? If you have any advice on what should I do in the process of restoring this pedal, I'll be glad to hear it.
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