This is the corrected schematic for the KAY256.LBR 256K ram modification

This is the corrected schematic for the KAY256.LBR 256K ram modification
for '83 series KayPro computers, Models II and IV. This one works fine!
Also, you Turbo-Rom users may want to see the text file TURBO256.TXT.

Many thanks to Dr. Liddle and to all those who debugged this fine
mod!

Charles McHan
AMY <> BBS
MULTI-SYSTEM
(904)725-7461

\_TABLE I\_

Signal on Chip on
Board Kaypro II/IV

REFRESH U48 pin 12
MUX U33 pin 1
A14 U33 pin 11
A15 U33 pin 10
RA7 U20 pin 9
RA8 U20 pin 1
PIO 1 Pad E29
PIO 2 Pad E28
PIO 3 Pad E31

\_FIGURE 1\_
\l0i
+-----------------------------+
| |
| +--------+ |
| +------| 7 |- 0v |
| | -| 4 |----------+
| | -| L |-
| | -| S |-
| | 0v -| 3 |-
+--|------| 9 |- 0v
| +5v -| 3 1|----------o----------< RFRSH
| +--------+ |
| |
33R | +--------+ |
RA7 <-- / /---|------| |- 0v |
+------| 7 |- |
+---------| 4 |- |
| -| L |- |
| -| S |- |
| -| 1 |- |
| 0v -| 5 |- 0v |
| +5v -| 8 1|----------+
| +--------+
|
| +--------+
+---------| |- 0v 33R
A14b >------------o--| 7 |------------ / /--------> RA8
\_| 4 |-----------------o------< PIO 2
PIO 1 >---------------| L |-< +5v >-/\/\/\_/ 4.7k
0v -| S |-----------------o------< PIO 3
A15b >---------------| 1 |-< +5v >-/\/\/\_/ 4.7k
0v -| 5 |------------------------< MUX
+5v -| 3 1|- 0v
+--------+