TEXAS TI-74 BASICALC & 8K RAM Cartridge teardown

[jebem]

TI-74 8K RAM Cartridge schematic diagram.

Battery cell unsoldered and removed and general parts view.




This a partial diagram but it covers all the PCB components.
The only missing details are the SRAM address and data lines but that is the easy part to figure out when needed.

Component list:
Double sided PCB.
IC1: HM6264LFP-15 8KByte CMOS SRAM 150nS.
D1, D2: 1N270 BKC (100V, 500mAp, Vf 300mV)
R1: 1K8 1/4W axial
R2: 3K3 SMD
R3: 150R SMD (PCB bottom side)
C1: 100nF 50V SMD
C2: 1nF 50V SMD
BATT: CR-2430 3V Lithium
30-pin connector.