E-Mu SP12 flea market find!

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dziugas2001
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E-Mu SP12 flea market find!

Post by dziugas2001 » Sat May 16, 2020 7:23 pm

Hello,
Today I have run into a great bit of luck. I was at a local flea market here in Lithuania, and I ended up finding a E-Mu SP12 in beautiful derelict condition, propped up on two shitty chinese speakers.
I went up to the seller and meekly asked "How much?", because I was expecting a ridiculous price.
What happened next turned my whole day upside down.
I was expecting a few hundred, maybe a thousand. I was there late, and there had to have been a reason for it sitting there for a few hours, while flippers and bargain-hunters wet past.
No. f**k NO.
It was 6€. I ended up paying the guy 7, because he didn't have enough change.
I'd feel bad, but he's a reseller himself. He deals in audio equipment all the time and just didn't bother to look at what he had. His loss, my gain. A deal is a deal.
When I came home I started to clean it up. It turned out very nice for 6 f**k EUROS. The reason I described it as "derelict" was because it was quite dirty, but all of the dirt was hiding a good example. I mean, there are flaws. Scratches, scuffs, some peeling on the top panel, but it's in good condition overall. The spot where the transformer attaches to the bottom panel is a bit bent outwards, possibly from a drop. But who cares.
I opened it up, and it looks beautiful inside. Barely any dust. The board reads: paul is a walrus or whatever the h**l the designers decided to put on it for a laugh. Still cool as h**l.
I have not turned it on yet. The cap for the fuse holder is missing, and I'll go get a new one and a battery next week. Then we'll see. But who really cares. If it doesn't work, I'll sell it off cheap (but for a lot more than I paid for it) to someone who wants to take on this project and has passion for synths, not just a flipper, because I hate inflated synth prices (all of your Jupiters, CS80s and Prophets and Moogs are (will) belong to us, when the economy crashes again and you'll need money to pay your debts or mortgages or whatever the h**l.)
I can't control my excitement, this is one of the coolest things I've found in a flea market (followed closely by the Macintosh Portable with great history, which I found a couple of years ago. Never got it working, though).
This proves that there still are amazing deals out there, and all you fellow synth heads need to do is get out there and look for that next treasure. Good luck!
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madtheory
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Re: E-Mu SP12 flea market find!

Post by madtheory » Sat May 16, 2020 9:09 pm

Amazing lucky find! It looks very good. Disconnect the power supply and test it. Most likely the PSU needs a recap.

Or, if you are gonna flip it and want to be sure not to damage it, sell it without powering it up.

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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Sat May 16, 2020 9:16 pm

Thanks for the tip, but I'd like you to elaborate a bit further. When I opened it today, it seemed like the PSU is integrated into the board, as in, there's nothing to disconnect. Is this a different revision motherboard of some kind, like an early one or something? I'll post a picture tommorow, I really want to get this thing up and running for myself, it's probably not going to be a flip, because it's a find I'm going to be proud of for a while.

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Re: E-Mu SP12 flea market find!

Post by madtheory » Sat May 16, 2020 9:26 pm

Ah, ok. It is integrated. Are you able test it i.e. with a scope? Failing that, do the caps near it look OK? Any bulges or leaks? A pic would help.

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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Sun May 17, 2020 11:48 am

Hello again,
Today I opened the E-Mu again and inspected the caps. They look fine to me, no bulging, no leakage and no bad smells around them (I had a Macintosh with bad caps that I mentioned in the OP and the electrolyte had a very specific, acrid smell), but maybe I'm missing something. It looks like replacing the caps wouldn't be hard, but I'd rather not touch them if they're not problematic yet.
Also, I calculated the ammount of RAM and it seems like this unit has the Turbo upgrade. I'm honestly not 100% sure, if someone can confirm it I've got a pic of the ramchips and eeproms.
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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Sun May 17, 2020 12:03 pm

Also, what in the h**l is this?
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Re: E-Mu SP12 flea market find!

Post by madtheory » Sun May 17, 2020 1:21 pm

OK, sounds like you know what you're doing. The only way to be sure, with caps though, is an ESR measurement. It's possible they're out of spec, even if they look OK. The bulging and smell is just further down the road of decay.

Those are zener diodes, or germanium diodes, doesn't look like a factory mod because they would not have soldered them that way. It's not secure. Are there any enginering revisions in the service manual? What's in the schematic there? Is it part of the memory circuit, or the DAC? If it's memory, it might make sense. If it's the DAC, I don't understand it.

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Re: E-Mu SP12 flea market find!

Post by blueknob » Sun May 17, 2020 1:28 pm

Nice find, I think everyone is entitled to find something special like this in their lifetime. If we don't hear from you again, to which prison shall we send the "file in a sandwich" :lol:

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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Sun May 17, 2020 2:32 pm

That diode thing is mentioned in the service manual: it seems to be an early engineering change that was later changed again ,the reason being is eliminating distortion on tom channels and improving sampling quality, so I'm not going to revert it, unless it ends up being too distorted. There are also some revisions that have not been done, like a chip that is described in the manual as being "a common failure point" that has not been replaced to the updated part, but the chips part no. (the one that is in the socket at the moment) does not quite match the original one (the one that was supposed to be replaced), so I don't know what to think. Although, most of the EC's that affect the machine seriously have been done (memory reliability, PSU grounding, audio noise ect.)

As for the caps, I looked into ESR testers and I'll see what I can get. I can't order one from china right now, because I'll be moving to another country in about 4 months, that would just be more luggage. I'll call around and see if a local repairman has this tool, it will be a bit of easy cash for them just to test these quickly.

Thanks blueknob, I have found some incredible stuff before but nothing like this. I just hope that I haven't exhausted my luck with this. As for the sandwich, send it to Alcatraz if I dissapear, and just write "To Big Bubba" on the envelope, I'll probably have enough noodles to buy it from him when it arrives. Also, I see that you have mentioned having a shedful of Ensoniqs, do you have any spare parts for a VFX? I've been desperately looking for a chip for the last few days, maybe this will be my lucky break.

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Re: E-Mu SP12 flea market find!

Post by madtheory » Sun May 17, 2020 8:29 pm

That's great! This instrument went to a good home ;)

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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Sun May 17, 2020 9:29 pm

Thanks a lot, madtheory! Although I do have to say, I'm not really an owner, I'm more of a temporary caretaker. I'll make sure to preserve this one, as I have watched a few demos, looked into the workflow and I really like what I see. Seems like these E-Mu's have a good reputation and insane values for a reason, and I'm really glad to own one.

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Re: E-Mu SP12 flea market find!

Post by ppg_wavecomputer » Sun May 17, 2020 10:28 pm

I at first was about to congratulate you on your find and tell you that you're in fact way beyond April Fools Day but this remark
dziugas2001 wrote:
Sat May 16, 2020 7:23 pm
[…] all of your Jupiters, CS80s and Prophets and Moogs are (will) belong to us, when the economy crashes again and you'll need money to pay your debts or mortgages or whatever the h**l. […]
is probably the daftest I have read in a while. :---)

This is not funny, and it isn't witty either.

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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Mon May 25, 2020 8:14 pm

Update: I have taken the E-Mu to a repair shop, capacitors were checked, they are still good.
I installed a new fuse holder and fired it up, nothing. No LEDs lighting up, blank display, no audio, just a hum from the transformer.
I checked the voltages, after looking through the service manual. Both of the digital 5V rails are at 0.3V, +15V analog rail is at 0.5, and the -15V rail is at... -15V.
So, back to the shop it goes. I found a really knowledgeable team of guys in a small shop, they seem honest and like they know what they're doing. I will come by later in the month and talk about a PSU rebuild, and I'll look into specialist options as well.
Also, Stephen, sorry for that dumb joke. I was on top on the world that day, and when I'm excited I tend to be extremely arrogant and say stupid s**t. But from the way that you took offence from that remark, I would assume that you actually own some of those legendary big polys that I mentioned, would you happen to have a CS80? That is my dream synth, and I'd really like to hear some thoughts from an actual owner, who has to actually deal with one of those.

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Re: E-Mu SP12 flea market find!

Post by dziugas2001 » Wed May 27, 2020 5:12 am

Update 2: I was checking some more voltages on the board yesterday. I wasn't finding that much stuff coming out of the transformer (20V and 18V from what I recall), so I thought that that was the culprit. I also looked at the regulators, and I got steady 5, 15 and -15V on all three, so I started thinking that there was a board issue. Checking the continuity I found that there were good connections to all of the testpoints, and then I lifted the top panel and saw that all of the LEDs and the display were working.
After playing around with it (and fixing one pad after breaking it while trying to clean it), it seems to work absolutely fine for the most part. Now I'll have to see if the PSU problems return, and if everything on the machine works.
P.S. I also found that the display still has a working EL backlight, so it seems like this machine hasn't had much use (apparently the displays dying is a common issue.)

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Re: E-Mu SP12 flea market find!

Post by rschnier » Sun Jul 12, 2020 5:44 am

Just came across this thread -- congratulations! I've had my SP-12 since purchasing it new in 1987 and will never part with it. In case you haven't already figured out, you do almost certainly have the Turbo model.

Or at least, you have the RAM chips for it -- whether it actually runs in Turbo mode or not is determined by a socketed PAL chip that's copy-protected at the factory; one variety of PAL chip for regular mode, the other variety for Turbo mode. Back in the day, E-Mu were real j**k about their upgrades -- they made you purchase the extra RAM chips from them (at prices way above market value) and supplied the necessary PAL chip to switch to Turbo mode along with those chips. When running in Turbo mode, the display will indicate "Turbo" during power up and the sample memory capacity will show the full 5 seconds rather than the standard 1.2 seconds or whatever it was.

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