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Hey all,
I’ve got a friend’s 7810 3 knob to fix up, it’s the export version with no transformer.
looking for some off board wiring help.
to start, it had a wire broken from the odd aftermarket barrel power jack to the rectifier, fixed that.. then found the 5554 dead. so i socketed it and made a drop in daughter board replacement with a 7815 and a 7915.
I believe someone, at some point, has messed around in the guts of this unit, as there is a large amount of insulation scraped off the traces in various spots, and one funny little jumper wire that doesn’t look stock.
Anyway. There’s one wire from the ring connection of the “boost in” jack that isn’t attached at the board end anymore, I’d love to know where it goes. Gut shots from other 7810’s would be awesome.
There’s also a funny little jumper I have included a photo of, from the IC under the Feedback pot to +15V, I’d love to know what’s up with that.
Also disregard the fluff on the circuit board, it’s from q tips. man this thing has a lot of rosin goo on it. only partly cleaned up.
Thanks in advance for any info, and hello from Vancouver BC, where I make my home, and mess with FX pedals occasionally.
Ryan
Well, I ended up replacing the whole power supply up to the dead 5554 regulator output traces, with an ICL7660SCPAZ based circuit.
I am really pleased with how well this worked for me! I was having a hard time comprehending the bipolar supply options, as this memory man wasn’t equipped with a transformer, and I wanted to use a supply I already had.
I used the layout found here: http://tagboardeffects.blogspot.ca/2014/01/bipolar-voltage-converter.html , and used 1N4001 diodes, and an additional 1N4001 on the +9v input, which helps get the output into the range needed.
I’m sitting at 14.6 to 14.45 volts with this setup depending on load, and the memory man seems OK with this unregulated supply.
I velcro’d the stripboard on to the memory man circuit board where the 470uf caps used to be, the output of the stripboard runs in to the 5554 V+ and V- output pin locations, 11 and 14.
I put a black wire from the stripboard ground strip hooked to one of the electrolytic filter cap negative lead pads, since it was available.
I also replaced the electrolytic capacitors, and the one tantalum capacitor I found, as a maintenance operation. the old caps and the rectifier are all housed in a plastic bag inside the pedal in case someone needs that extra mojo/noise some day.
I’m not used to noisy old delay pedals, but on this Economy Memory Man I think there’s a certain level one must live with. a great sounding pedal anyways, really cool.
I replaced some of the solid core wiring with stranded, a little less fragile.
Question: there’s a quiet though audible sweep type sound when the pedal is in chorus mode, not sure why this is audible, and how I might go about silencing it.
It’s a great chorus too though, nails some Andy Summers tones right out of the gate.
I’ve enlarged and upped the contrast on the available schematic, so that I could print it out. I can read just about everything now and nice to have it on paper.
If anyone has the export version schematic, I’d love to see it some time! Just curious.
I haven’t often shared my repair and rebuild projects online, this time round it felt right, as I benefited so much from everyone who has taken the time before, doing the same.
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