19 Jun
2011
19 Jun
'11
10:45 a.m.
It seems reasonably straightforward. I've managed to read the contents of a
few 27C256 EPROMS successfully. However, I couldn't read the contents of
the BASIC-PAC 2k masked ROMS? I'm sure I have all the jumpers and switches
right for a 2716, which I understand is an equivalant EPROM chip . All I
I'm not sure it is an exact equivalent.
The Sorceror ROM Pac seems ot ahve jumper links associated with each ROM
chip (these are shown on the schematic with no explanation!). From what I
rememebr, one set of connections for those links will let you use 2716s,
but there are, of ocurse, orther arangements of links for chips with
slightly differnet pinouts.
In generaly, the +5V, grpound, data pins and the lower order address
lines are onm the same plins for EPROMs, masked ROMs, etc. But things lik
chip selects, and the higher address lines may move around a bit.
What I would do is look at the ROM Pac PCB that you took thise ROMs from,
and work out just what signal is on each pin of the ROM. You may want to
trace the conenctions with an ohmmeter. Of coruse the schematic is very
useful too here.
You then have a pinout of the mask ROMs. You cna compare tht against the
known pinout of a 2716 to see whatis different.
if you replace the defective ROM with a 2716, you may have to reconfigure
the links to get the signas on the right pins. Foprtuantely, there are
separate links for each ROM chip, so you can have a mixture of types on
the board.
-tony