Korg Poly800 / Poly800 II -1984    Weight = 9.5 Lbs. Number mfg.= 100,000 MRP=$795

User Manual: Patchell's page
Reset Proceedures: N/A
Operating System code: Sepulveda's ex800 page
MIDI or other control protocol: rlsnuffy
Software related Links: N/A
Patches or knob settings: rlsnuffy mkII sounds or Factory.wav
Circuit Overview: below
Scematics/Service Manual: fdiskc archive or Patchell's page
Common Service Issues/Tips: below
Parts Sources: Keys knobs semiconductors misc
Uncommon chips/modules used: Korg 2069BDB VCF (NJM2069BD), MN3209/MN3101/NE570 (replaced by Digital delay on Mk II)
Modifications:'moogslayer' mod Hey..I didn't make up the name :-). It's basically just a panel break out for trim pots to give wide control of filter settings. Also FM800 to add dco mod to vcf.
General Info Links: Vintage Synth Explorer

Circuit Overview:
     8 DCO's with one Korg Filter...so a mix of polyphonic and paraphonic. I have not studied the architecture in detail on this one...some day. The II which I have adds digital delay though in place of BBD ensemble effect.

Service Tips:
     The machine I have was a lot of bad solder and cleaning issues. Generally fairly reliable I think. Mine had a cool problem when it midi-looped. A cyclic runaway repeating midi stream took it down to the same bizarre sound on every patch. I had to reload patches. This, being right before i saved the arrangement of course. I was just moving it into my midi setup after playing it for months and getting used to those sounds...gotta love it. I have to hold the 'most patches lost' record. At least the II has sysex loading and some of the factory sounds were pretty identical to some I liked.

UPDATE! I got back into these and figured out a few things. First the MIDI destruction was happening whenever I sequenced to it. The problem, believe it or not, was corrupt data in my MK2. The mk1 may be immune to this though corrupt data can also exist in a MK1 I see.

Another common problem appears to be Q1 blowing open. You'll measure between Base and collector a forward drop but not base and emitter. I replaced with bigger NTE378 and it works fine (reverse the leads). Anyway this problem will cause the unit not to power up at all. Seen this twice now so it's probably fairly common. Save you a ton of tracing time knowing that :-). Send donations to make up for the first time it happened to me and I had to figure out where everything went. :-)

Strangely also, I just worked on a couple of these in a row. Neither appeared..to have ever had a battery installed! Bizarre. Well they are set up for Lithium. Diode blocks them from receiving charge. Here is a link for detailed replacement instructions. Also I'm told that many of the earlier units were set up like this so that you had to have batteries in the external access battery bay to hold memory!

Another issue you may encounter are ERROR numbers. Someone posted in a yahoo group this tidbit regarding an error 6:

 This means you have corrupted data in the third flash ROM. Which means you need to reflash the software into the third ROM.
> Error 4 - first block of flash ROM
> Error 5 - second block of flash ROM
> Error 6 - third block of flash ROM.

I don't believe Korg has any support for these now. I have some parts including filters, so feel free to ask what the current stock is on a given thing. These are common and cheap on ebay.< Contact