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Subject: Re: [korg_mono-poly] Keyboard Tunning Problem

From: Florian Anwander <fanwander@mnet-online.de>
Date: 2019-05-15

Am 15.05.2019 um 14:19 schrieb vcfool vcfool@gmail.com [korg_mono-poly]:
> Up to 5V all is good, but I can't get up to 6V. Highest C is 5,97V.
>
> I just noticed that the arpeggiator set to Full also shows the problem
> on the highest octave.
>

As first step I would check the resistors R21 and R19 on the CPU-Board.
You can see in the schematic of the board
(http://www.florian-anwander.de/korg_monopoly/mp_09_klm-356_uP_ArpIn_schemo.gif)
that Korg changed the values of those two resistors.

R21: from 221Ohm to 196Ohm (1%)
R19: from 289kOhm to 143kOHm (1%)

Maybe your Monopoly has the old values.




Another approach might be to try the adjustment procedure somehow
"reverted":

have the "tune point" open
1. adjust VR1 so that you read 6.000V when playing a C5 in UP transposition
2. check for 3.000V in MID position and C3, if not ok, adjust VR-3
3. check for 1.000V in DOWN position and C2, of not ok, adjust VR-2
Repeat the steps 1 to 3 until the high notes are ok.

No warranty, that it works from my side, but it might be worth the try.



Florian


--
http://www.florian-anwander.de