Korg Poly800 not triggering oscillators.

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Korg Poly800 not triggering oscillators.

Postby michael stein » Tue Sep 02, 2008 8:00 pm

Can this synth be reinitialized? I sent it a midi reset message from my computer and the Oscillators disappeared. The noise source still works and all the modulation and envelopes still work. This is very wierd. I have had all my digitally controlled synths with analog filters go wacky b/c of midi related things.
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Re: Korg Poly800 not triggering oscillators.

Postby Maschinengeist » Wed Sep 03, 2008 6:49 am

I'll have to dig up my service manual... but I don't remember a key sequence or something like that to reinitialize it. I know there is a "hard reset" possible though.

At first sight, I'm a bit baffled. I don't have ready-made answer. I'll try to seriously sit with my documents.
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Re: Korg Poly800 not triggering oscillators.

Postby michael stein » Thu Sep 04, 2008 7:30 pm

Thank you for any suggestions or advice you may offer.
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Re: Korg Poly800 not triggering oscillators.

Postby ThunderbirdsAreGo » Wed Apr 22, 2009 11:09 am

Hi I just joined up as i'm resurrecting a neglected Poly800 for playing about with

It is the earliest model and has no internal backup battery
Anyone know where to fit one (I will download the schematics soon but I suspect they only show the MK2)?

As it is now, there are some sounds, no.53 seems half there, but most programs just make a noise burst and maybe fade into a tone after some delay. There is the helicopter flutter noise on the stick, and pitch change also. Is this the normal condition when the memory is flat? I expected it to have lost any sequencer program that was programmed in, but not the basic sounds (I might mean to say "patches") but I dont know if it has a fault or has just lost its marbles due to being left off for 10 years.

Next question; I would like to restore it to factory sounds. Is this a matter of downloading "patches" as WAV files and feeding into the tape port?

I will finish reading the manual my main problem is I dont understand some of the synth musical terms having had an older sister bang a piano every evening and become a music teacher left me a bit tone deaf! I'm fully up with electronics though as thats my hobby and day job.

Any pointers appreciated
Ralph
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Re: Korg Poly800 not triggering oscillators.

Postby meatballfulton » Wed Apr 22, 2009 12:15 pm

That is normal behavior. The power supply batteries are also the memory backup. Check the main circuit board, many of the original P800s have a space marked to mount the lithium battery, it's just not installed...mine was like that. Here's a photo that shows where the battery goes.

Image

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Re: Korg Poly800 not triggering oscillators.

Postby michael stein » Wed Apr 22, 2009 7:47 pm

That is how mine acted when the battery died. Works now since it has been repleced. I have an mp3 with original factory patches somewhere that ill look for.
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Re: Korg Poly800 not triggering oscillators.

Postby ThunderbirdsAreGo » Thu Apr 23, 2009 6:51 am

Thanks guys, my particular unit serial #013263 has no mounting tracks between IC 18 & IC 19 however the other parts and tracks are there and C 88 has 9V across (running on 9V power supply)

Looks like if I cut the tracks add the link and remove the bits I should be able to put a lithium batt across where C88 is

The bits of sound i get have changed since yesterday but I'll worry about that once a batt is in there.

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Re: Korg Poly800 not triggering oscillators.

Postby ThunderbirdsAreGo » Fri Apr 24, 2009 11:56 pm

I have put a lithium batt in across what was C88 and cut the diodes from the track - all seems OK. )My previous post I should have said there was 4 V across the c88).

Loaded the replacement patches from here

http://www.geocities.com/SunsetStrip/St ... info2.html

It took quite a lot of trials the USB sound from my main PC wasnt suitable had to go to a PC with AC97 audio and even that required an external amplifier to work sufficiently to make all the display flash and not too much or it dropped out to "err" I think the patches are a rough recording from an old tape - just like loading software into a Sinclair Spectrum - but I'm thankful that the patches at least exist.

I'm not sure if I will make the external mods to it, probably just the 2 knobs mod will be enough, I marked all the presets (shouldnt touch VR1) and worked VR2, VR5 a bit to test the waters and got scalded - it probably depends which patch is used for testing this, must note to keep my amp turned down

So thanks for the help its got an otherwise junked Poly running as it should
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