[sdiy] PROM Replacement for Spider

[Roman Sowa]

DigiKey has a thousand of them, but anyway, I wouldn't buy them because 
of the price and age.
Whenever I need to replace old EPROM I pick most common, cheapest and 
easy to get OTP EPROM, which usually is AT27C256. It has 28 pins so 4 of 
them will be outside of the socket, which typically can fit on the old 
board without pushing other components. After programming just wire 5 
pins together: 1,2,26,27,28

Or you may fance making breakout board for PLCC EPROM

forget about buying newly made EPROM smaller than 256kb

Roman

W dniu 2026-01-27 o 16:16, Raf Wlodarczyk pisze:
> Hello list,
> 
> The supply of the IM6654 PROM i use in my Spider clone has dried up and was wondering if anyone had suggestions on how to use a modern part for a replacement.  IM6654 is a 8x512B device so could using a AT28C512 on an adapter do the trick?  My PROM/EEPROM knowledge is limited so any help would be greatly appreciated.
> 
> -R
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