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Subject: Re: P6 battery voltage readings: does this look right?

From: "r_j_d_2.phila" <r_j_d_2.phila@yahoo.com>
Date: 2009-12-28

thanks alot andy.

so here's where i'm at: R91 and D15 are definitely oriented right. C40 was removed, yes. C36 was also replaced before as well. so, here's some more readings:

from battery + to IC25 pin 14, i get .66V. this stayed the same if i removed IC25. HOWEVER:

from battery + to IC32 pin 18, i get .66V. if i remove IC32, this drops to 0V. but, most other pins of IC32 will read 1.3-1.7V with IC32 removed.

where does this put me? also, i have a 3.6V rechargeable, new, battery i bought last week(nickel-something or other, not cadmium, but its rechargeable). do you think this would work? i really just need to have the machine work for the next 5 months, as im gonna be gigging with it. is that an option, or do i need to fully source the problem for ANY battery to work? if not, where do i check now? 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 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]
>