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The final step, the 1088XE.
Version 2.0(This one works!)
By Scott Peterson, June 1986.

Well, this is it for me, the last installment on the 130XE. I have not built this mother, but one has been built and tested by 
another person in Mass., and it works!!


This doc assumes you have allready built and tested a 576K 130XE. to finish it you will need the following parts;

Quanity  part no.  description.
-------------------------------
  16    41256-15  256K DRAM'S
   1    7432      quad OR gate
   1    7404      quad invert buff.
   2    33 omh resistors.
Small piece of PC board.
-------------------------------
Note: On the 74 series, you can sub them with 74LS series chips, they use less power...

Tools;
Nothing fancy, a fine tip soldering iron,screwdriver,needle nose pliers, and some fine wire, ect.

Mount the 7404 and the 7432 on a small PC board(1in. X 2in.) connect together pin 14 on the 7432 and pin 14 on the 7404 
with a length of fine wire. This is the +5v supply to the chips, connect it to pin 14 of any 14 pin chip in the 130XE or 
pin 16 of any 16 pin chip in the 130XE. Next connect a lenght of wire to pin 7 of the 7432 and pin 7 of the 7404, this is 
ground for the two chips, connect it to pin 7 of any 14 pin chip in the 130XE or pin 8 of and 16 pin chip.

Next, take U23(U23) out of the socket and bend up pin 17, reinsert it in the socket. Solder a piece of wire to pin 17 U23, 
and connect it to the 7432 pins 2 and 5. Next connect a wire to pin 14 on U23(PIA) run it to pin 1 on the 7404 and pin 1 
on the 7432. Now connect a wire from the 7432 pin 6 to pin 17 of the socket U23 is in. Find the 74LS138 you piggy backed 
to the mother board when doing the 576k mod, remove the jumper from pins 1 and 16. solder a wire from pin 3 of the 7432 
on the PC board to pin 1 of the piggybacked 74LS138. Run a jumper from the 7404 pin 2 to the 7432 pin 4. Put some double 
backed tape on the PC board and stick it somewhere on the mother board of the 130XE.


RAM-CHIP installation(lots of them!)

Take the 16 new ram chips and cut pin 15 on all of them in half so only the 'fat' part is left. Now, you have to piggy back 
them on-top of the 64K drams(the left-most row of chips). Solder in 8 of them, connecting all pins except pin 15, then connect 
a jumper to pin 15 of each new ram chip. Make sure you have about  a foot left over. Solder in the next 8 doing the same 
thing(you might want to piggy back the 256K DRAM's prior to mounting them on-top of the 64K DRAM's). When you get done you 
should have 2 new rows of 256k DRAM's solder in on-top of the 64K DRAM's, with a 2 wires, one connected to all the pin 15's of 
the middle row and another connected to all the pin 15's of the top row. Take one wire and go out a few inches and install a 
33 ohm resistor in-line, cover with heat shrink tubing and do the same to the other wire. Connect one wire to pin 15 of the 
74LS138 and the other to pin 13 of the 74LS138. Last but not least, install a jumper to pin one of each of the left bank of 
ram-chips, just like you did in the 576k mod to the bank on the right. After doing this run the jumper to any pin one of the 
right bank, what you should wind up with is a common connection to every pin one of both banks of ram-chips.

Your done!!!
Sorry, as of right now I know of no software to run on this(maybe Mydos 4.2? or Top-Dos 1.5+). I will provide a table for the 
control numbers, ect.

-------------------------------------
Bank#    Control#   Hex#
-------------------------------------
1          1         1
2          3         3
3          5         5
4          7         7
5          9         9
6         11         B
7         13         D
8         15         F
9         33         21
10        35         23
11        37         25
12        39         27
13        41         29
14        43         2B
15        45         2D
16        47         2F
17        65         41
18        67         43
19        69         45
20        71         47
21        73         49
22        75         4B
23        77         4D
24        79         4F
25        97         61
26        99         63
27        101        65
28        103        67
29        105        69
30        107        6B
31        109        6D
32        111        6F
33        129        81
34        131        83
35        133        85
36        135        87
37        137        89
38        139        8B
39        141        8D
40        143        8F
41        161        A1
42        163        A3
43        165        A5
44        167        A7
45        169        A9
46        171        AB
47        173        AD
48        175        AF
49        193        C1
50        195        C3
51        197        C5
52        199        C7
53        201        C9
54        203        CB
55        205        CD
56        207        CF
57        225        E1
58        227        E3
59        229        E5
60        231        E7
61        233        E9
62        235        EB
63        237        ED
64        239        EF
-------------------------------------

That's all of them, 64 16K banks for a total of 1,024,000 bytes extended ram and 64,000 bytes of 'normal'(?) ram. I have a tester 
for this one but thats it for right now. Like I said earlier, There is a working model, It was built by Dennis Porter of Mass. 
His many long distance phone calls made this work.
 
                   Good Luck
                     Scott

P.S. 2 meg is very, very possible. You just need wwuunnn more control line. This would have to be bit 0 of the PIA, but you would 
lose the switch-able O.S. Its up to you guys from here, thats funny, the 1040 ST only has 1,024,000 bytes of ram.

