Timex Sinclair 2068

Spectrum-compatible BASIC with AY sound, joystick ports and a cartridge dock.

Chips

Chip	Where	Role
Timex SCLD (TS2068)	U3	Video, DRAM control, bank switching, clocks, keyboard, tape and beeper for the TS2068
Z80A CPU	U19	Main CPU (8-bit, 40-DIP)
AY-3-8912 sound chip	U14	Three-voice programmable sound generator with one 8-bit I/O port
23128 Mask ROM 16K×8	U16 (Home ROM, NEC 23128, 250 ns)	BASIC and KERNAL ROMs (C16, Plus/4, C64C short board, C128)
TS2068 Extension ROM (2364, 28-pin)	U20	Extension ROM: bank switching and extra BASIC routines, Extension Bank $0000-$1FFF
4416 DRAM 16K×4	U6, U7 (video RAM, TMS4416-15); U12, U13, U17, U18 (upper 32K, TMS4416-20)	C16 main RAM (2 chips = 16 KB); C128 VDC video RAM

Power in (AC adapter), DC barrel, 5.5 mm OD x 2.5 mm pin
TV RF output, RCA phono, VHF
MONITOR (composite video), RCA phono
EAR (tape in), 1/8 in (3.5 mm) mini phone jack
MIC (tape out), 1/8 in (3.5 mm) mini phone jack
Joystick ports (2 x DE-9, left = player 1, right = player 2), DE-9 male, one each side of the case
Cartridge dock (J4, 2 x 18), Card-edge socket under the TCC door, 18 + 18 contacts
System bus (P1, 2 x 32, rear right), PCB card edge, 32 + 32 contacts, slot at 6
Keyboard connector (J9, internal), 14-pin single-in-line flex connector (AMP Trio-Mate 1-520315-4)

Rail	Expect	Measure at
Power in	14-25 V DC (SUM: about 21 V from the stock adapter)	Barrel sleeve; P1 B3 after the switch
+5 V	4.75-5.25 V	78S40 switching regulator U1 output; Z80A pin 11; SCLD pin 43; AY-3-8912 pin 3; P1 B4
+12 V	11.5-12.5 V	78L12 regulator U8 output
GND	0 V	Z80A pin 29; SCLD pin 26; AY-3-8912 pin 6