Backup RAM errors...

After testing later that day it popped up again with "00D00000 5555 5540"

This will be a repair I think.

Here some pictures:









It does look like some corroded traces :'(.

MKL said:

Now this is incredible...

besides the 1-slots I also got a 2-slot from the same arcade op, again with a backup ram error but this time it involved both ram chips:

http://img.photobucket.com/albums/v65/nassivera/backupramerror2-slot2.jpg

And guess what the problem was?

http://img.photobucket.com/albums/v65/nassivera/backupramfixed3.jpg

yup, both rams had the same broken trace from pin 27 to the 74HC32...

Problems were not over though as after repairing the ram traces the board booted with a calendar error:

http://img.photobucket.com/albums/v65/nassivera/calendarerror.jpg

This was due to a certain trace broken in three (!) points. Repairing this trace gave me a fully working 2-slot:

http://img.photobucket.com/albums/v65/nassivera/calendarerror2.jpg
http://img.photobucket.com/albums/v65/nassivera/calendarerror3.jpg

And I have yet another faulty 1-slot from the same op...

Click to expand...

This was incredibly helpful. Thank you for sharing!

I was able to fix a 'Backup Ram error - Address 00D00000 - Write 5555 - Read 55FE' error by running a jumper wire from pin 6 of HC32 to pin 27 of the second backup RAM chip.

Hi can anyone tell me how to teack this code im fairly new to this all but i have a back up ram error have checked the traces but no luck in seeing anything visible code is 00d0000 AAAA AAFE any help would be awesome

mik*87 said:

Hi can anyone tell me how to teack this code im fairly new to this all but i have a back up ram error have checked the traces but no luck in seeing anything visible code is 00d0000 AAAA AAFE any help would be awesome

Click to expand...

Use a hex to binary converter. Bits are read right to left so a normal status of 5555 should read as 0101 0101 0101 0101. Lowest bit on the right and highest on the left. If the error when converted to binary changes some of the values in the string then you know where to look. So if the error converts to say 0101 0101 0101 0111 you can see the second bit is wrong, so you then check the second bit on the Backup RAM. Each RAM has 8 data lines, one is the upper half and one is the lower half. In this case you would check the lower half, second data line. That's the quick and dirty of it.

I'm medicated right now so if anyone needs to correct that please do.

Thankyou ill try that