Thanks for the ideas so far. Let me restate the problem. Once the A/C adapter is connected and powered, there is no response from the keyboard (the adapter is fine). In fact if you are playing it with batteries, and then plug in the adapter (whether powered or not) the keyboard shuts down.. Is there a component that is likely the problem that is breaking the circuit when I plug in the A/C adapter? If so, can you give me the circuit board reference from the service manual below? (Thanks to whoever upload that!) Again, this is a first generation Poly-800.
http://f1.grp.yahoofs.com/v1/4IW5ScC_ONNXYVwY83LaSNqAQ2MExSOXkNWuRG65B_k86OpCNzYiTVGP-D_OwFLJJF_NrEdMAZTIKcm30LiMv8AO1Fn6xPd3jV_WvRk/1%29%20Poly-800/Servicing/Korg%20Poly-800%20Service%20Manual.pdf
--- On Thu, 3/12/09, Gordon JC Pearce MM3YEQ wrote:
--- On Thu, 3/12/09, Gordon JC Pearce MM3YEQ wrote:
From: Gordon JC Pearce MM3YEQ
Subject: Re: [korgpolyex] Poly 800 A/C Adapter Issue
To: korgpolyex@yahoogroups.com
Date: Thursday, March 12, 2009, 2:03 PM
On Thu, 2009-03-12 at 10:07 -0700, TheTravelSource Fes wrote:
> I tested at the 9v DC in point with the A/C adapter plugged in and
> batteries in place. The voltage came to 18V which I understood as the
> adding of the batteries and the A/C adapter. Any thoughts as to why
> that would/should be? Should there be a cut off of the batteries once
> the 9v adapter is plugged into the socket? Thanks for any further
> thoughts.
> By the way Diode 2 which prevents against reverse polarity was fine.
> -Johnb
>
>
Sounds a bit wrong, actually. That would mean that the batteries and
mains adaptor are in series. Is the adaptor the right polarity?
Gordon