12 Mar
2005
12 Mar
'05
12:25 p.m.
At 11:29 PM 3/5/2005, you wrote:
I recently attempted to modify a decserver board
to use the 11/53 roms. I installed the pullup and
burned the images into a pair of am27128A-2dc eproms,
but when I powered up the board it couldn't pass test
#1 with the "KDJ11-D/S 1.00" message.
I have successfully modified a DecServer board with the pullup resistor,
but your experience sounds familiar to me. It has been a while since I did
this conversion but I seem to remember that there was a ROM contents
checksum in the PDP11 boot and you had to burn the new rom completely to
make sure all the locations were correct.
I reverified the contents of the eproms and thought
that I must've damaged the board when installing the
pullup. Just to be sure though, I remapped the 11/53
images with "cat 261E5.bin 261E5.bin > 1.bin",
"cat 262E5.bin 262E5.bin > 2.bin", then erased the
original 27256's and burned the new images into them.
I think I tried this, burning two copies of the 128 ROM into the 256 ROM,
and it didn't work without the pullup resistor. I could be wrong since I
am old (probably equal to the average age of people on this list) and MY
memory may be failing!
After reinstalling these I powered up, and the board
came up okay:
9 8 7 6 5 4 3 2 1
Commands are Help, Boot, List, Map, Test and Wrap.
Type a command then press the RETURN key:
So my question is, did I botch the pullup install
or did I use the wrong eproms? What eproms should
work in the kdj11-sd? The originals were am27256dc.
My next step is to test a teac fd55gfr 149-u5 floppy
drive for use as an rx33. It appears to have the
correct jumpers, but I haven't seen it listed as
one known to work. Can anyone confirm whether
this model can be configured as an rx33?
Thanks,
--
Eric Josephson