UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Nascom repair

julie_m · 30th Oct 2017, 4:58 pm

If "tanning" is a problem for you, it was certainly possible in the days of the BBC Micro to use a 6264 (I think that was the part number) 8k * 8 SRAM IC with an auxiliary lithium battery back-up supply, as a substitute for a 2764 EPROM. The BBC used only memory ICs designed to run from a simple 5V supply (no +12V, -5V or -12V). Most of the pins are just passed straight through; the rest are carefully bent out of the way and the IC stood in a 28-pin DIL socket.

You would have to handle it very carefully to prevent corruption, but it should be possible to program as a "special voltage" 2764 and then connect it to the NASCOM motherboard.

30th Oct 2017, 4:58 pm	#20
julie_m Dekatron Join Date: May 2008 Location: Derby, UK. Posts: 7,735	Re: Nascom repair - Looking for clues please If "tanning" is a problem for you, it was certainly possible in the days of the BBC Micro to use a 6264 (I think that was the part number) 8k * 8 SRAM IC with an auxiliary lithium battery back-up supply, as a substitute for a 2764 EPROM. The BBC used only memory ICs designed to run from a simple 5V supply (no +12V, -5V or -12V). Most of the pins are just passed straight through; the rest are carefully bent out of the way and the IC stood in a 28-pin DIL socket. You would have to handle it very carefully to prevent corruption, but it should be possible to program as a "special voltage" 2764 and then connect it to the NASCOM motherboard. __________________ If I have seen further than others, it is because I was standing on a pile of failed experiments.