| Part# | EPROM Type | Description |
| 444-319 | 2708 | ET-18-9 basic ROM |
| 444-221 | 2532 | ET-18-4 Utility Rom |
| 444-239-1 | 2532 | ET-18-7 Automode Rom |
| 444-110 | Main (Monitor) ROM 1.0 | |
| 444-110-1 | Main (Monitor) ROM 1.U | |
| 444-198 | Main (Monitor) ROM v1.1 (4MHz) | |
| 444-198-1 | Main (Monitor) ROM v1.3 (4MHz) |
a 2532 may be substituted for a 2732
HM6264LP-15 MEMORY
HM6264LP-12 MEMORY
6116 Memory
The 6264 is a 8K Static RAM Chip (8K
x 8 Bits = 64)
The 6116 is a 2k Static RAM Chip (2K x 8 Bits = 16)
The ROM upgrade path is:
Version 1.U replaces Version 1.0 and uses the 3.59 MHz Crystal
Version 1.3 replaces Version 1.1 and uses the 4.oo MHz Crystal
Version 1.U and 1.3 contain the routines to make the Serial Interface work. If
You install the Memory Expansion you should use the 1.1 or 1.3 AND make sure you
have a 4.oo MHz crystal installed on the CPU board. This keeps Hero's timing
circuits in sync and can sometimes explain erratic behaviors.