128k RAM expansion
BOM list:
1 x HM628128
1 x GAL20V8
1 x 74HCT273
2 x 100nF ceramic capacitor (C2, C3)
1 x 330R resistor (R1)
1 x 1k resistor (R2)
2 x LED diode (D1, D2)
1 x switch (SW1)
A single wire mod to your ZX Spectrum 48k is required to disable the 32k upper RAM
For Issue 2/3/4 connect pin 5 on IC23 (74LS32) to pin 14 (+5V)
For Issue 6 connect pin 35 on IC27 (ZX8401) to pin 40 (+5V)
Designed by Ji?í Veleba
128k RAM expansion
*PCBWay community is a sharing platform. We are not responsible for any design issues and parameter issues (board thickness, surface finish, etc.) you choose.
CERN-OHL-P-2.0 License
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