Re: omega race hig score save

If you have a scope available, you should try to capture the levels at pin
19 and at pin 18 when (or if) a pulse occurs at pin 20. That would prove
whether or not the control signals were present and behaving properly.

If you don't have a scope, and since you've likely eliminated most of the
possible logic related problems, I think that it is likely that you have a
discrete component problem.

Measure the voltage at pin 17 of 5101. It must be a logic high while the
game is on. This level provides an active-high chip select. Without it,
the chip does nothing at all. This signal is provided by all that discrete
component stuff next to the 5101 in the schematic. The zener D108, Q102 and
Q103, R143 (and several other res's).

When the game powers up, it'll read the 5101 only once and then display the
results. When you get a new high score, it'll try to save the value once
but it'll probably continue to display the correct value as long as power is
not lost. If the 5101 isn't working, you wouldn't know it at that point.

William Boucher
----- Original Message -----
From: "andre" <livnfree_can@yahoo.com>
To: <vectorlist@vectorlist.org>
Sent: Friday, October 31, 2008 7:26 PM
Subject: Re: VECTOR: 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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>> problems to chris@westnet.com
>> >
>>
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>
>
>
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Received on Sat Nov 1 11:28:36 2008