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, Andrew Jury <andy@...> wrote:
>
> ...and a Merry Xmas to you and everyone else in the group! If you don¹t do¹
> 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]
>