Random ebay find from stoneagegaming.
https://www.ebay.com.au/str/stoneagegaming
Plan
Photograph
Document
Teardown
Test Chips
Create PCB for ROMS
Clean PCB
Scan PCB
Retrace in KiCAD Schmentics
Rebiuld PCB
If Chips are fired?
PCB
REV “G”
Intergrated Circuits
Processor
U301 – Intel 8080A c1974
Clock
Clock Generation with U313 – DP8224
Bus Controller
U302 ??? – Intel D8228 – System Controller and Bus Driver for 8080A CPU
Peripheral Interface
U303 ??? – Intel P8255A c1981 – Programable perpheral Interface
24 Programmable I/O Pins
RAM
U318 – Motorola MCM6810 – 128×8 Bit Random Access Memory
U31? – Motorola MCM6810 – 128×8 Bit Random Access Memory
ROM
U304 – Texas Insterments TMS2708JL-45 – 1024 Word x 8 Bit uvEPROM in CERPAK
Marked
1156-87
98F4
U305 – Texas Insterments TMS2708JL-45 – 1024 Word x 8 Bit uvEPROM in CERPAK
Marked
1156-88
8FC6
U306 – Texas Insterments TMS2708JL-45 – 1024 Word x 8 Bit uvEPROM in CERPAK
Marked
1156-90
?8191
??69
EPROMS are going to need some work to read them being NMOS and Strange Pinout….
JL is Ceramic Package
45 is 450ns access time
RS232?
There is a baud select switch with “110” on it so this might be some sort of serial
Pin
1 110 baud 1 + 2
2 75 baud
3 150 baud
4 300 baud
5 600 baud
6 1200 baud
7 2400 baud
8 4800 baud
Missing Chips
U397 –
Power Supply
looks like dual full bridge rectifiers with 4 regulators