Fixing, Restoring and Modding a Korg Poly-800!

I was given this 1985-era Korg Poly-800, as it was not working - and was going to be thrown away! In this video, I look at the synth, diagnose and fix the problems, restore it to full operation - and then make it better than ever, by installing the "Moog Slayer" mod, as well as a switchable 12/24db filter. I then demonstrate how the synth sounds with these mods installed!

Thanks so much to MissParker for the very generous gift of this Poly-800. It will be put to good use!

I was asked if I could share the links for the parts I used to fix the Poly-800, so here they are:

0:00 Introduction
1:13 Unboxing and Inspection
2:43 Testing
3:43 Disassembly
4:36 Replacing the Battery
5:51 Checking & Cleaning Jacks
6:33 Tactile Button Problems
7:15 Reassembly
7:43 Reloading Factory Presets
8:29 Test Playing
9:31 Replacing Tactile Buttons
12:24 Replacing Jacks
14:19 Installing Moogslayer Mod
16:06 Installing Filter Mod
18:48 Cleaning Pots
19:19 Test playing and Demoing Mods

#Korg #Poly800 #Moogslayer

[giovaxx]

Back in 1990 I reverse engineered its firmware and patched it to make the cutoff filter respond to dedicated MIDI CC messages in realtime. It improved a lot!

[kelvindodd]

Thanks Scott. I just pulled my old Poly 800 out and will be refreshing it. Bought it new.

[Asmuk]

One of the best videos I watched at YouTube for a long time. Quite useful, thank you so much.

[daveogarf]

You are one very fortunate man, sir! I'd LOVE to have a Poly-800 after playing a friend's years ago. The quirkiness is kinda' fun, and the sounds are somewhat unique. Thanks for the vid!

[jamesdefrancesco]

Great vid. I have the ex800 and replaced the soldered battery holder as well. The buttons are also a nuisance but will work. That single filter is good but paraphonic is a bummer. However, as I watching this vid I realized that my new Solina is also paraphonic. Time to midi them together and see what happens. That 6 stage envelope is fun.

[gohkawai]

Thank you for creating this video. I have a KORG Poly-800 that I purchased new in 1985. It powers on but generates no sound, just like the one you repaired. I will refer to your video in order to restore mine. Thanks!

[hubbarao]

Love your channel man, thanks for sharing all this! I subscribed when I realized you've helped me several times (Cobalt 8 firmware upgrade and general care tips). I found this video on accident trying to figure out why I couldn't load patches from tape. Thanks for the reminder to do the Moog Slayer mod! I plan to tackle this soon.

Couple notes: My patches load but I never got the "Good" message that I had when saving/loading/verifying with actual tape recorder instead of a smartphone. Seems to have loaded okay regardless (at least most patches). My tact switches are touchy but I just use the bank hold (only use this in the studio). Also, corroded audio jacks can often be fixed by rolling fine grit sandpaper and giving the inside of the jack a quick scrub. Just wanted to share, maybe it helps someone. Thanks again!

[JayKaufman]

You got super lucky with that battery not eating away at traces. These and a decent number of Korg synths from the same era (Poly 61, Poly 6, etc.) are quite well known for the batteries leaking over time and absolutely tearing the boards to shreds thanks to the acid.

A few years ago these weren't even worth repairing because of it, but thanks to everything synth that's old being worth more money now, they're worthwhile repairing.

[juliprivate]

oh my, I have a non working poly800 sitting in my basement... totally need to go through the same procedure 🙂thanks for reminding me

[paulr]

I love this. Why on earth would anyone downvote it?

[palmacbeth]

thanks. i love the content and pace of this video. thanks for measuring up the buttons and posting the link to buy the replacements.

[jjdekay]

A great save! always good to have the right tools nearby to get a job done the "cat scan" sure does help in diagnostics.

[sandymissparker]

There are no words...this is amazing. xo

[cassettedisco]

Amigo saludos desde México 🇲🇽 sabes tengo un Poly 800 pero no sé si sirva crees q podrías hacer un tutorial enseñando un poco del mantenimiento gracias ❤

[b-north]

hey i literally just got one for free and it’s super clean physically but it don’t work, watching this definitely is helping me, i might contact you for more information if that’s ok with you

[deanbrndo]

Would look really nice with a volume knob the same as the res and cut off.well done.

[mattisopen]

Superb presentation and clear description of how to restore this great little synth. Like some of your other commentators, I’ve had one of these instruments from new and 40 years on have two different problems that you weren’t able to cover as my model is one of the first and does not have back up battery, but relies on the type C batteries to back up the sounds, and when these expire, one loses the programmes. I’ve bought a CR2032 holder and the appropriate battery, but how do I wire it in and let it take over from the C batteries? Second issue: on turning the machine upside down I’ve upset the joystick, which has now gone limp. How do I fix this? It’s not broken as such, just limp and won’t stand up. You can still get modulation, but not pitch bend?
PS: Although there’s a space on the board where the battery would go (in the future models) there are no terminals to wire the same onto the board, hence my fundamental problem.

[richardelam]

great video....i have a poly800II that needs some components replaced
due to dampness issue. do you or could you help me identify which
resisters need to be replaced. thanks...would love to get it working
again

[MattPopOfficial]

The volume dial on my Korg Poly-800 half works, in that it raise the volume on the left channel only, unless I apply a little pressure (push it down) which makes the right channel join in. Is there an easy way to fix this?

[mrbungledisco]

Awesome video, thank you for sharing. Subscribed!