On Fri, Jan 18, 2013 at 11:34 AM, Chris Jones <chris@...> wrote:
On 18/01/2013 11:24, Alexandre "tabajara" Souza wrote:
Chris, probably you're missing two addressing lines to upgrade it to
4mb. I think i have a newer board with
More memory, but it is some 600km away, i'll take a look at it as soon
as i can
The DRAM chips only need one more address line to be 4Mbit rather than
1Mbit (they're a matrix, not a linear array), and that address line (pin 5)
is definitely wired up (to one of the PALs, if I remember rightly) on this
CPU board, which is what made me think the upgrade was worth a try. The
full story is here, complete with wiring details:
<>
I would be interested to know what a newer 16500A CPU board looks like.
I've seen distant photos of them on eBay which appear to show SIL memory
chips.
Now I've installed ROMs version 00.02, and the 16500A has developed a new
fault: the self-tests 'HIL Controller', 'Front Panel' and 'Touch Screen'
all fail. I thought it was a software problem but putting the old 00.00
ROMs back in the problem is still there. I'm hoping it's just a bent pin on
the backplane connector or something but it's very annoying to get this far
and have a new fault to deal with, apparently unrelated to the RAM.
Has anyone got experience of what's likely to cause these three self-test
failures?
Chris
