Discussion about the Korg PolySix synthesizer

Hello guys, sorry for the late response...

First of all, I forgot to mention that I know almost nothing about electronics and schematics, and I also need to learn how to use unimers properly. 
I gave my best to decipher the schemes but I think the best way is for you to look at the pictures of the board here:



http://img17.imageshack.us/img17/2954/img0020uwi.jpg
http://img5.imageshack.us/img5/5016/img0021c.jpg


I can tell that C40 has been removed and that R91 has been replaced but I could not find D15 (I presume that's the one right under R91).

Cheers,
Milan


--- In PolySix@yahoogroups.com, "Chromatest J. Pantsmaker" <chromatest@...> wrote:
>
> Maybe a bent lead on the ram, shorting itself?
> 
> I agree with Andy.  The guy didn't fix it right.
> 
> On Thu, Mar 5, 2009 at 7:03 AM, Andrew Jury <andy@...> wrote:
> > Hi Milan,
> >
> >
> >
> > You should take the board back and tell him he hasn't fixed it properly! ;-)
> >
> >
> >
> >
> > Seriously, it does sound like there is an excessive load across the
> > terminals of the battery. Before you do anything else then please make sure
> > that R91 and C40 have been moved from circuit. D15 should not have been
> > touched and the new diode (should be a 1N4148 or similar) is soldered in
> > place of R40 with the anode facing toward the anode of D15. If the new diode
> > is connected in reverse then the 5V rail will be connected to the battery
> > whilst the Polysix is switched on! (and also the battery will never power
> > pin 18 of the SRAM, if it is not destroyed already!).
> >
> >
> >
> > If all the above look right connect an ohm meter across the battery
> > terminals making sure the Polysix is disconnected from the mains and the
> > cell is also removed. What resistance do you get? If it is below 1K ohm then
> > start pulling the SRAM and re-measuring. IC25 and C36 are also candidates
> > for failure as they are directly connected to the battery whilst the power
> > is off.
> >
> >
> >
> > Let us know what you find.
> >
> >
> >
> > Cheers,
> >
> > Andy
> >
> >
> >
> > From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
> > mekonin
> > Sent: 05 March 2009 08:44
> > To: PolySix@yahoogroups.com
> > Subject: [PolySix] Having problems after battery replacement
> > - Show quoted text -
> >
> >
> > Hello good people from polysix support group.
> > I have one pretty annoying problem with my beloved polysix and I was hoping
> > if you could help me.
> >
> > I got it back from repair few weeks ago.
> > I had the notorious battery problem, and the tech guy fixed almost
> > everything except one thing.
> >
> > He replaced the chip which I think is controling the memory, and it is
> > draining too much power.
> > We measured almost 30mA, which he says is way too much.
> > So instantly, when I put the fresh Lithium battery, the voltage goes from
> > 3.3V (or something) to 2.8V, and it takes a few days for the battery to be
> > completely depleted (the synth is off all the time).
> > He is 99% sure it is that chip that is causing the problem,
> > and he suggests me that I find an original one, because he was unable to.
> >
> > The chip is the replacement for TC-5514, it's 2114 I think.
> >
> > I have checked if D15 diode is facing the right way, if it's not then the
> > battery would be routed to ground with 100 ohm which is something about
> > 30mA..
> > But it's facing the right way.
> >
> > I looked at the datasheet for the original TC5514 memory chip and it says it
> > needs up to 180mA in operating and 10mA in standby. The 2114 also uses 10mA
> > in standby but 100mA in operating mode, so it's a newer and more efficient
> > chip. It doesn't make sense that it's this chip that's making the problem.
> >
> > Thanks in advance guys.
> > Cheers,
> >
> > Milan
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> > - Show quoted text -
> >
> >
> > ------------------------------------
> >
> > PolySix "Digiest" Page: http://www.acc.umu.se/~amber/Poly6Yahoo! Groups Links
> >
> >
> >
> >
> 
> 
> 
> -- 
> .sig
> -Chromatest J. Pantsmaker
> http://www.chromatest.net
>