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Subject: Re: [korgpolyex] Re: Killed my poly mkII installing Hawk800 kit

From: Michael Hawkins <korgpolyex800@...>
Date: 2009-11-04

Paul,

I would start with a multimeter and measure the +5volt rail and carefully adjust it using VR1 near the power regulator (top left hand corner looking from the front of the main board).

I've had two HAWK-800 customers with kits that placed just a little more load on the power supply to bring it under the required minimum (+4.75).

You should adjust it to be as close to +5.0 volts as you can. CAUTION: Be careful not to send the power too far over 5 volts.

Then go looking for your intermittent problem.

Mike.



From: crustypaul <bullshit@...>
To: korgpolyex@yahoogroups.com
Sent: Wed, November 4, 2009 1:23:54 PM
Subject: [korgpolyex] Re: Killed my poly mkII installing Hawk800 kit

 

On further investigation i don't think this has got anything to do with the Hawk800 and i've just knocked something while installing it.

There appears to be a bizarre problem with something in the power supply area. If i screw the main board down tight the poly starts up fine but the pitch is wavering all over the place, either that or the pitch starts to rise for no apparent reason until the poly restarts. The fact that it starts up might have something to do with the main board grounding.
If i touch the main board anywhere near the power input the pitch wavers with the amount depending on how hard i press on the board. If i press it too hard the poly just resets.
I'm thinking theres some kind of intermittant short around the power supply somewhere but it could take some time to track it down. Would the fact that the pitch is actually proportional to how hard i press on the board suggest what component has the problem to anyone?

--- In korgpolyex@yahoogro ups.com, Paul Cunningham <paul@...> wrote:
>
> Flickering out might indicate a power supply problem, where pressing a
> button puts an additional load on the defective/underpowe red power
> supply and causes a CPU reset. Have you tried running on batteries or
> using a different (larger) power supply? -pc