Thanks! We’re really enjoying digging through it. Nothing in here is custom made (other than that coil). It’s all off-the-shelf components (albeit circa 1984!) so in now which way an impossible task.
An update on our progress: When I first received the Linn, it didn’t boot up at all. No sound, no LEDs, nothing - just dead in the water.
My son cleaned up the corrosion from the dead nicad batteries and re-tinned some suspect traces on the main board. New nicad batteries were installed (this time with a DIY battery holder so we could more easily swap them out). We put it all back together and… no dice. Still nothing.
However, once we removed the disk drive and associated microfloppy controller card, it showed the first stirrings of life - the LCD sprang to life, informing us that this was OS 7.07 (the last from after-market Linn service masters Forat). It hung there indefinitely, though.
Still, it was something!
Next I pulled out all of the cards except the SRAM card. I tried it again and it actually booted! The front panel LEDs came to life and the buttons seemed to be working. Next, I stuck the bass/snare/sidestick card in and rebooted. Again it came to life. It wasn’t out of the woods yet, though. A quick test of the associated pads revealed that they worked, as did the volume and pan sliders. However, the sounds were very strange and glitchy - though they were consistent and responded to velocity and such. I then tried recording a quick pattern with the glitchy sounds - and it worked!
After replacing the remaining cards, I found that all of the drums were plating back in this odd, distorted manner. I am thinking maybe the sample playback clock is too slow.
It froze up on me a couple of times, but a reboot fixed it each time. So, though this big, broken piece of history isn’t up and running properly yet, I am pleased that some progress has been made (and I will likely try to sample those glitchy drum sounds before attempting to work on it again - watch this space!)
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Rare Linn 9000 warped circuit sample food? 
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The sheer number of daughter cards in this puppy is kinda insane. 
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Yeah, there’s definitely been some Forat mods on this thing. The OS is 7.07, which isn’t the last Forat OS, but almost. The Disk drive has a signature and says “Forat” in Sharpie on the top cover. There is a SMPTE mod, but I don’t know if that was Linn’s or Forat’s, as it still says Linn Electronics on the SMPTE board (however, I seem to recall that this particular unit had that installed by Forat in the early 1990s).
Alas, we’ve taken two steps forward and one step back. We had OS booted and working pretty well, though it only played back glitchy sounds. However, now it’s hanging on the OS version screen again. Still, it gets us closer to knowing what’s going on. At a guess, I think the sounds I was triggering may be played back at the wrong rate, with all of the aliasing and artifacts that might cause. In any event, I sampled them while I could, trimmed them and converted them into a sample chain for Digitakt/Rytm users and a sliced file for Octatrack users. I tested them on all three machines and they worked well. If you want to have a play with them, you can download them from this link:
http://www.theelectronicgarden.com/Scot/Glitch9k_2.zip
I included one-shots, too. No editing - these are just the raw sounds as they were spit out of the broken Linn 9000. I tracked the Linn through a spiffy Chandler Limited/EMI Abbey Road REDD.47 pre-amp - though that probably doesn’t matter much in this case!
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Yes, thank you for sampling…
Warped sounds from a classic vintage drum machine’s failing circuits sounds very appealing…
Sneaky almost, in a “this track has heritage but you’ll have no idea why” kinda way… 
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I’ve added an OP-1 drum kit version to the zipped file, hence the altered name of the file in the link above. If you have an OP-1 and want to use those samples you can re-download the zipped folder.
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What a great father son restoration project! Love it. All the best of luck on the next step.
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For the OP-1 users amongst you: I’ve just re-uploaded the zipped file with a new OP-1 version of the kit. I had made a sort of pitched sound out of one of the samples to play melodically with the top six notes of the OP-1, and realized that it may have been tuned too low for the notes used. There is now a version with pitched notes that match the actual note values on the keyboard.
That is so cool! Awesome gear + family project. Those will be some great memories to look back on.
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Nigel (my son) and I have been building and repairing gear for nearly a decade. He is very smart - he could read a schematic at the age of 10. He’s now a young man (21) and knows far, far more about this stuff than I could ever hope to learn. A couple of years ago, we built an entire modular synthesizer from the ground up as a gift for a friend. His DIY analog sampler module was the crowning piece in the cabinet - really special (unfortunately the sampler module was also really difficult to design build and he has steadfastly refused to make one for my own system).
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Well, you must be proud of him, good stuff and great legacy. I wish you well.
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Hi Scot,
Did you happen to find the source of why it was creating these glitch sounds ? I have a Forat Linn9000 I acquired not too long ago in a very similar state that yours was in. It seems to freeze when the disk controller card is in but if I take that out it boots up fine as well as records and plays back sequences, but the drum sounds are glitchy. Curious if you found the issue on your Linn.
In my case, I never got too far before I had to set the project aside. I contacted Bruce Forat, who informed me that I simply needed to load any and all sounds from disc to get anything other than glitchy noises from it. I checked with the previous owner who confirmed that he had indeed had every ROM slot replaced with RAM, so there are no onboard sounds. As I didn’t have any disks, and because Forat only sells the entire (and massive) collection for hundreds of dollars, I put the project on hold and, well, sort of forgot about it.
Once the pandemic dies down, I will likely get back into it, though.
Interesting ! Thanks so much for your response. Mine came with 1 floppy disk, but seems like the problem is coming from that disk controller card. I’ll probably call Bruce to see if there’s anything else I can try.
For all I know, my problem is a bad card or some other failure. However, it would cost me quite a lot to find out. As far as I can tell, Forat is the only place to get disks, so I’m left with buying the whole collection just to find out that it doesn’t help me. And the thing is, I don’t really use samples I don’t make so I am not sure if it would be worth it to me. 
Right totally, I understand that. I’m not sure if it’s worth it either, but would be curious to see if it’s anything I can try to fix myself or trade for another drum machine of some sort !
I would say definitely not worth fixing, unless you’re an obsessive about sequencer timing and “feel”, which was it’s thing. I sampled it and moved on.
Here’s my kiddo playing with it (almost 20 years ago! Wow.)
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Absolutely not obsessive (well, or about those things, anyway 
) but this particular unit has some personal history and meaning for me, so I’ll get it going someday!
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