Re: Ram Error

Uriah wrote:
This is maybe not a basic question but I guess it is all relative. I
am working on a arcade game board that is operated by a M68000. (Neo
Geo 4 slot). It comes up with a "Work Ram Error" I am pretty sure the
ram is ok. I have compared it many times with a few Huntron style
testers. There are about 6 SMD RAM chips. It shows an address and then
what was written AAAA and what was read AAEA. Can someone provide me
with some tips on how to track down the fault? The 68000 is tied to
three custom 100+ pin smd chips and it is real hard to follow the
traces to be sure because the board is not translucent and many of the
traces go under chips. But what is the process generally used to wire
up RAM and what could cause this read error? Are RAM chips generally
wired directly to the M68000? Or do they have to go through some type
of controller? Can a read error like this be caused by an open or
short in the trace or is this something that is only caused by faulty
logic in the RAM or faulty logic in another chip. It seems there are
no short cuts but there is also no documents on this board. No
schematics, no pinouts on the custom chips and no theory of operation.
I am sure someone understands this more then I do.
Thanks again
Russ

While cycling the test, spray freezer on half the board and then the
other half, gradually localising it the while.

If you are lucky you might be able to repeatedly make the problem worse
or better when only one chip only is frozen, if so change it.

Cheers
Robin

.

Relevant Pages

  • Ram Error
    ... It comes up with a "Work Ram Error" I am pretty sure the ... There are about 6 SMD RAM chips. ... traces go under chips. ... no pinouts on the custom chips and no theory of operation. ...
    (sci.electronics.basics)
  • Re: 1977 original apple II restoration (continued)...
    ... Firstly I swapped out all the RAM for some that I recently purchased, ... Pushing reset does nothing. ... *two* bad DRAM chips. ... You should also take a *very* close look at the board traces to ...
    (comp.sys.apple2)
  • Re: Asus A7V8X RAM :[
    ... > no other RAM in the motherboard and it was error free. ... > Also I talked to someone in my comp sci class, he told me that Micron ... A double sided memory has two ... As for what channels the memory chips are taking, ...
    (alt.comp.periphs.mainboard.asus)
  • Re: IEEE-488 bus
    ... more ram (heck, i have 512mb ram sitting here for a year since my pc ... The bus would take into account not only what we just discussed (dual ... Real chips used or FPGA, ... Minimum system is the C64 architecture and glue logic. ...
    (comp.sys.cbm)
  • Re: 800XL memory problem
    ... If so, should I buy those chips and send them to you, or will you get them and I'll pay them for you? ... If it goes straight to memory test and shows red, i'm sure the problem is in your RAM. ... Be aware some DRAMS have a slow bleed effect, meaning if you turn your Atari off and right back on, it might not come up correctly because the RAM has not had enough time to bleed down to 0. ... I would say if they aren't socketed to go ahead and replace them with sockets and try the RAM, that way if they don't work how you want then you can just buy the correct replacements and do a simple swap. ...
    (comp.sys.atari.8bit)
Loading