From: Giles Humpston
...the attached 3 JPEG files, which have [been] circulating in the UK for some years. They show you how to install a 32k RAM chip in your NEC for less than 5 dollars. The chip is also still in production! The current drain of these chips is much lower than the NEC ones so your batteries also last much longer. Some familiarity with electronics is required to do the modifications, but I can confirm they work. I believe the circuit should be attributed to a gentleman named Alan Galpin.

Memory Module Instructions: Page 1  Page 2  Page 3

Memory Module Instructions: - contains original high resolution images