ColecoVision

Z80 + TMS9928A + SN76489. Boots cartridges, no BASIC.

Chips

Chip	Where	Role
Z80A CPU	U1	Main CPU (8-bit, 40-DIP)
TMS9918A / TMS9928A / TMS9929A video display processor	U9 (TMS9928A)	Video display processor (VDP) with its own 16 KB DRAM bus. Composite out on 9918A; Y, R-Y, B-Y on 9928A/9929A.
SN76489 / SN94624 (TMS9919) sound generator	U20 (SN76489AN)	Three tone voices and one noise voice, written over an 8-bit data bus.
4116 DRAM 16K x 1	U10-U17	Dynamic RAM, 16K x 1 (lower 16K on the Spectrum)
2114 SRAM 1K x 4	U3, U4	Static RAM (ZX80 and ZX81 1K)
9464C-0036 BIOS mask ROM (ColecoVision U2)		OS-7 BIOS, $0000-$1FFF
2764-pinout 8K x 8 ROM	U2 only after the EPROM conversion (solder traces cut, jumpers WJ4/WJ5 fitted). A stock board has the 9464C mask ROM, whose pins 2, 20 and 23 differ: see 9464C.	8K x 8 ROM or EPROM in the JEDEC 2764 pinout.
74LS138 3-to-8 decoder	U5, U6	3-to-8 line address decoder.
74LS541 octal buffer (controller inputs)	U18, U19	Buffers the controller port lines onto the data bus. U19 reads port 1, U18 reads port 2.

Power input (J3), Coleco 4-pin power socket, pins on the console
Cartridge slot (J1), 30-contact card-edge socket UNVERIFIED
Controller ports (J5 port 1, J6 port 2), DE-9, male on the console
Expansion module interface (J2), 60-contact card edge on the main board (front, behind the door) UNVERIFIED
RF output, RCA phono jack (channel 3/4 switch beside it) UNVERIFIED
RF board riser (J4, internal), 8-pin riser from logic board to RF board UNVERIFIED