Re: Asteroids Vector RAM Read/Write Problems

Just out of curiosity, how did you confirm the rams are good?

Also, how did you confirm the rams are being selected?

Thanks,
-Mark

On Mon, Jan 24, 2011 at 12:09 PM, Dave Langley <
dave2084.forums@googlemail.com> wrote:

> Sadly the all 4 RAMs are good :-(
>
>
> On 23 Jan 2011 10:48pm, Kevin Moore wrote:
>
> Well I'm certainly no expert on these things. But If the selects are
> toggling, and Vector Rom reads out good. Then I would suspect bad ram on M4
> or R4 or both.
>
>
> Kevin
>
>
> On Sun, Jan 23, 2011 at 1:16 PM, Dave Langley <
> dave2084.forums@googlemail.com> wrote:
>
>> Yes, as far as I can tell both pairs are being correctly enabled when I
>> RAM test the approprate range using the 9010A. I might confirm the signals
>> look got on my 'scope though just to be sure.
>>
>> Is the /ram being selected? Chips L3 pin 12, M5 pin 4, and 6?
>>
>> On Sun, Jan 23, 2011 at 2:30 AM, Dave Langley <
>> dave2084.forums@googlemail.com> wrote:
>>
>>> I'm trying to fault find an asteroids board with Read/Write Problems on
>>> the vector RAM.
>>>
>>> So far I've done the following:
>>>
>>> The game arrived with no display and two tones indicating E2/E2 RAM
>>> Fault; I quickly traced the fault to M5 pin 11 being stuck low so the RAM
>>> was never selected.
>>>
>>> Now the game gives two high tones and two low tones. When using my Fluke
>>> 9010A I am getting a R/W error on bits FF for all addresses in the range
>>> 4000 to 47FF. The vector ROM however gives the correct checksum (CBED) so
>>> the buses must be OK?
>>>
>>> Does anyone have any idea where I can go from here?
>>>
>> --
>> Dave Langley
>>
>> ---------------------------------------------------------------------------
>> ** Unsubscribe, subscribe, or view the archives at
>> http://www.vectorlist.org ** Please direct other questions, comments, or
>> problems to chris@westnet.com
>>
>
>
>
> --
> Dave Langley
>
> ---------------------------------------------------------------------------
> ** Unsubscribe, subscribe, or view the archives at
> http://www.vectorlist.org ** Please direct other questions, comments, or
> problems to chris@westnet.com
>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Tue Jan 25 14:37:50 2011