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Please note also - THIS BLOG ENDS HERE WITH THE LAST ENTRY FROM NOVEMBER 9th 2021.

I have prepared a new blog with wordpress at https://vintagecomputing.info !!!

Thank you.

Almost all Amstrad/Schneider PC1512 web pages disappeared meanwhile.
I tell you that, because I looked for hints about upgrading my PC1512 from 512KB to 640KB RAM. After all, that wasn't too difficult, although it's NOT enough just to insert 16 pieces of 4164-120 Dynamic RAM chips (64KBx1 per chip). You have to set a jumper too, unfortunately this wasn't documented in the manual nor on a web page I found.
There are really A LOT OF SCREWS to be removed, until you can take a look at the mainboard:

The smaller red rectangle shows the jumper position. The jumper was hidden by the metal plate/radio shield which covers the mainboard. You have to remove the shield also to see the jumper :-(
This costs at least 2 hours of disassembling and reassembling, but success is sweet:


P.S.:
Wikipedia is wrong with the description of the RAM upgrade.
There is written "it could be upgraded to 640K of RAM with an expansion pack commonly known as a 'top hat'". there is no such "expansion pack". You need only 16 DRAM chips each with 64KBit memory. Nothing else.

P.P.S.: There is a tech manual online, and if you know the words you have to look for, you will find also the hint for the above mentioned jumper, see "related Link".