Discussion about the Korg PolySix synthesizer

thanks andy.the IC i replaced #32 with is a TMM314APL-1. i was told this was a workable sub. is there a better one out there? thanks.

--- In PolySix@yahoogroups.com, Andrew Jury <andy@...> wrote:
>
> Hi,
> 
> Sounds like progress to me. I tried to get you a typical current reading for
> the SRAM but couldn¹t measure anything. I then took a look at the data sheet
> and found that the device draw 20uA max! A bit smaller than my DMM can read!
> So under normal circumstances the having the SRAM in circuit should draw
> very little from the battery indeed. This is why a lithium cell should last
> well over 5 years in this application. If upon connecting Vdd of the chip
> the battery starts to run down then perhaps there could well be a problem.
> What is the exact SRAM in use you have there? It should be a Toshiba
> TC5514APL-3 which is a 1024 word x 4 bit device. Perhaps you are using an
> incorrect part with a higher current consumption. However, I doubt it, I was
> be more inclined to a faulty device. Do let us all know!
> 
> Cheers,
> Andy
> 
> 
> 
> 
> 
> On 28/12/2009 15:13, "r_j_d_2.phila" <r_j_d_2.phila@...> wrote:
> 
> >  
> >  
> >  
> >    
> > 
> > ok, so i have new data: after removing the SRAM chip and leaving the machine
> > off overnight, the battery RESTORED itself to about 2.8V! im assuming that's
> > good.
> > 
> > for the record, my RAM chip, IC32, had been damaged, so i had replaced it with
> > a socket. i have popped the 367 board, and verified every trace on IC32, and
> > also inspected it for any traces bridging. it all tests 100%. i bought a
> > replacement IC, but it might have been a pull.
> > 
> > so, 2 questions:
> > 1-could my RAM chip be pulling the battery down, but functioning correctly
> > otherwise? the machine writes/saves/functions properly in the programming
> > regard.
> > 
> > 2-if so, does anyone have a lead on a good replacement chip? thanks-rj
> > 
> > --- In PolySix@yahoogroups.com <mailto:PolySix%40yahoogroups.com> , Andrew
> > Jury <andy@> wrote:
> >> >
> >> > ...and a Merry Xmas to you and everyone else in the group! If you don¹t
> >> Œdo¹
> >> > Xmas then at least I hope you are enjoying a nice break...
> >> > 
> >> > The battery is there to keep the supply running to the memory subsystem
> >> when
> >> > the mains power is off, right! This means that pin 18 of IC32 and pin 14 of
> >> > IC25 are presented with the battery supply. If you are using a non
> >> > chargeable cell and you replaced R91 with a 1N4148 signal diode then make
> >> > sure it is polarized correctly. That is with cathode (line) facing towards
> >> > the cathode of D15. This allows the battery to supply the two ICs in
> >> > question whilst the supply is off but keeps it isolated (diode is reverse
> >> > polarized) when on.
> >> > 
> >> > You should also remove C40 which is now redundant. If you haven¹t done so
> >> > then this could possibly be the cause of the problem, if the component is
> >> > dried up and no longer working as originally intended. Also check C36 to
> >> > verify it is not causing a problem in circuit. You are also quite safe to
> >> > remove this and power the circuit on whilst testing. Finally, lift pins 18
> >> > and 14 as described again and see if that makes any difference to the load
> >> > on the battery.
> >> > 
> >> > If you are using a 3v lithium cell, such as a CR2032 then you should have
> >> > about 3.1v offload and about 2.9-3.0v on load. The figures you sent us do
> >> > not describe a circuit which is working properly. Get soldering and let us
> >> > know what you find...
> >> > 
> >> > Cheers,
> >> > Andy
> >> > 
> >> > 
> >> > On 26/12/2009 20:50, "r_j_d_2.phila" <r_j_d_2.phila@> wrote:
> >> > 
> >>> > >  
> >>> > >  
> >>> > >  
> >>> > >    
> >>> > > 
> >>> > > greetings, all-happy holidays. got a P6 battery question, to follow up
> >>> on my
> >>> > > draining battery issue:
> >>> > > 
> >>> > > i've taken the 367 board out, and cleaned/checked all of the traces
> >>> around the
> >>> > > battery area. i didnt see any resistance at a low reading level that
> >>> looked
> >>> > > abnormal. i installed a battery clip socket. now, here are my battery
> >>> readings
> >>> > > for a brand-new battery:
> >>> > > 
> >>> > > -OUT OF MACHINE=2.7V
> >>> > > -IN MACHINE, MACHINE OFF=1.5V
> >>> > > -IN MACHINE, MACHINE ON=2.4V
> >>> > > 
> >>> > > does this look normal? i probably wont know for another day or two if it
> >>> > > drains, but wanted your feedback on if these readings sound normal.
> >>> thanks, rj
> >>> > > 
> >>> > >  
> >>> > >    
> >>> > > 
> >>> > > 
> >> > 
> >> > 
> >> > 
> >> > [Non-text portions of this message have been removed]
> >> >
> > 
> >  
> >    
> > 
> > 
> 
> 
> 
> [Non-text portions of this message have been removed]
>