Sorry another quick question.... for the FDC board I want to reroute some of the traces so that I can use a 2732 EPROM for the DOS.
Looking at the schematic I think I need to make the following changes - could somebody sanity check this for me before I start cutting tracks...
Modification steps:
Pin 21 on the PCB is connected to (VPP), Pin 21 on the 2732 is (A11) so Break the original VCC connection to pin 21.
Run a wire from the Pin 18 trace to the PCB pin 21 connection, and break
the connection of this trace to Pin 18 to leave Pin 18 NC and route A11 to Pin 21.
Pin 20 on the PCB (PD/PGM) → Pin 20 on a 2732 (/OE) - No changes needed both active low for read.
The now NC Pin 18 on the PCB corresponds to Pin 18 on the 2732 = (/CE) so connect this directly
to pin 20 so that /CE and /OE are both directly driven on the 2732 by the same signal.
Looking at the schematic I think I need to make the following changes - could somebody sanity check this for me before I start cutting tracks...
Modification steps:
Pin 21 on the PCB is connected to (VPP), Pin 21 on the 2732 is (A11) so Break the original VCC connection to pin 21.
Run a wire from the Pin 18 trace to the PCB pin 21 connection, and break
the connection of this trace to Pin 18 to leave Pin 18 NC and route A11 to Pin 21.
Pin 20 on the PCB (PD/PGM) → Pin 20 on a 2732 (/OE) - No changes needed both active low for read.
The now NC Pin 18 on the PCB corresponds to Pin 18 on the 2732 = (/CE) so connect this directly
to pin 20 so that /CE and /OE are both directly driven on the 2732 by the same signal.
Statistics: Posted by JonnoW — Sat Feb 07, 2026 9:59 pm