Datel Action Replay PC

PCB components:

The front side of the PCB, with labels (created by me)

Name	Type	Manufacturer	Name/Value	Pins	Info
U1	EPROM	National Semiconductor	NM27C010	32	datasheet
U2	Dual Flip-flop		HC74A	14	datasheet
U3	SRAM (8KB)	Hyundai	HM6264	28	datasheet
U4	SRAM (128KB)	Hitachi	HM628128LFP	32	datasheet
U5	555 Timer	STMicroelectronics	NE555	8	datasheet
P1	Programmable Logic Array	AMD	PALCE20V8Q	24	datasheet
P2	Programmable Logic Array	AMD	PALCE20V8Q	24	datasheet
P3	Programmable Logic Array	AMD	PALCE20V8Q	24	datasheet
P4	Programmable Logic Array	AMD	PALCE20V8Q	24	datasheet
C1	Capacitor
C2	Capacitor
C3	Capacitor
D1	Diode
D2	Diode
R1	Resistor
R2	Resistor
R3	Resistor		1K Ω
J1	Connector		DB-9 male

Firmware:

The firmware is 128 kilobytes, separated into 16 8KB Pages. Each page begins with a header that says which page it is, and mentions "(c) 1993 DATEL"

The AREPLAY.COM file has error strings for "Action Replay ram not switchable" and "Replay base address is not being shadowed" which suggests the larger SRAM chip (U4) is being used to shadow the EPROM at runtime.

There was at least one upgrade to the EPROM provided, which involved mailing out a replacement chip to users.

Anti-virus functionality:

The firmware contains the signature of 50 viruses, starting at offset 0x164D8.

Each name is proceeded by an 0xFE character, can be up to 26 letters long, and is padded with spaces.

IBM Control

The external "paddle" features a button, switch, and LED. The PCB inside calls it the "Datel IBM Control"

DB9 (female)

	Connection	Color
1	N/C	N/A
2	LED	Brown
3	Switch	Black
4	Button	Blue
5	Ground	Green
6	N/C
7	N/C	Yellow
8	N/C
9	N/C
Shell	N/C	Orange

Credits:

The firmware contains credits at offset 4F64: (TODO: See if you can view this from within the program)

                  Action  Replay  v1.3         (c) 1993 DATEL
           Programmer ............................ Simon P.Constable
           Project Manager ......................... Wayne H.Beckett
           Design ................................... Mike J.Connors
           ......................................... Wayne H.Beckett
           Hardware .................................. Roy C.Harding
           Support .................................... Mark Wallace
           .......................................... Damon P.Barwin

Twitter Threads:

• When the Brandon unit first showed up on ebay (April 24th, 2019)
• In response to the LGR video (February 21st, 2020)
• Firmware image reverse engineering (February 25th 2020)
• Status update after the card arrived (February 27th, 2020)

Related Links:

• Lazy Game Reviews video on the Action Replay PC
• Manual, PCB images, and software
• VCFed thread
• Version 4 firmware dump