Re: omega race hig score save

If I go into bookkeeping and can see my highscore before the game is powered down, then the chip 'is' being written to correct? I tried an extra battery, and it made no dif. Tried 4 different 5101's.. also replaced the 74138 and comparatored the other 3 74's and they looked fine.. at a loss on these..

--- On Fri, 10/31/08, William Boucher <boucher@mnsi.net> wrote:

> From: William Boucher <boucher@mnsi.net>
> Subject: Re: VECTOR: omega race hig score save
> To: vectorlist@vectorlist.org
> Date: Friday, October 31, 2008, 12:39 AM
> I was looking at the schematic tonight just out of
> curiosity, even though I don't have the game myself.
>
> I found a datasheet for the 5101. Most of what I've
> been reading on some sites is that 3.6V at pin 22 really
> isn't quite enough to keep it up. That datasheet
> however specifies that 2V is enough to hold data.
> Apparently, 4.8V will not hurt the thing, since it runs on
> 5V anyway when the game is on, so maybe you could simply try
> 4 cells. That would explain why both boards failed to hold
> the data when off. According to the datasheet, 4 cells is
> overkill.
>
> It looks like the 5101 is enabled by a lot of things, one
> being that crazy over-complicated transistor circuit (Q102
> & Q103) which looks like it's only there to tell the
> 5101 when the main power is on or off (via pin 17 chip
> select or CS2). If the pin 17 signal fails to come up, the
> 5101 will not enable writes to it so your hi-score would not
> be saved.
>
> Another is the pin 19 (active low "batram" which
> is chip select CS1) signal coming from the 74138 at location
> PN2. Then there's all the chips that enable the 74138
> such as the 7404 inverters at S6 & PR1, and the nand
> gate at P4. A fault in any of these 4 chips would prevent
> the batram signal from being generated.
>
> Another is the pin 20 (active low write) signal. Is that
> being generated? If it is stuck high, it can't write.
> If pin 18 (called RD but is actually output disable) is
> stuck high, the data can't get out onto the bus and so
> the game can't read it.
>
>
> William Boucher
> ----- Original Message ----- From: "andre"
> <livnfree_can@yahoo.com>
> To: <vectorlist@vectorlist.org>
> Sent: Thursday, October 30, 2008 7:48 PM
> Subject: VECTOR: omega race hig score save
>
>
> > I have a couple boardsets I added battery packs to. I
> replaced the 5101 on both as well. The battery packs are 3 x
> 1.2v for 3.6v as I believe that is what the original single
> battery was rated at. But neither board saves the high score
> still. I measure 3.5v on the 5101 with the machine turned
> off, but it still restarts with the 'AE' generic
> highscore and not any other one I get. Any ideas why its not
> working? The 5101 in the sockets were also both checked for
> continuity and passed.
> >
> >
> >
> >
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>
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Received on Fri Oct 31 19:26:55 2008