Folks,
I have read pdf schema at:
http://msx.retro8bits.com/msxdocs/msxturbor1mb.pdf
However I have some questions.
I don't need to cut any connection on R800 CPU (like on ST), just to wire 36, 37, 38 and 41 pins as on diagram below?

Then I need to solder strap at J302, connecting the two solder points (making a jumper) ?
And finally, desolder R352 (a SMD resistor), and put it on R353 ?
That's all? Nobody tried 60ns memory on GT? I know 70ns has problems, but what about 60ns?
Thanks,
Fernando
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Just speculating here, relevant Turbo-R docs are still Missing In Action (I know Turbo-R schematic is available, I'm talking about complete pin functions / datasheets for R800 & Turbo-R engine IC's).
I put a similar circuit in a Sanyo Wavy of mine once, and it did what it was supposed to do (add read-back for D5 mapper bit). Sanyo Wavy 2+ shares a lot of tech with a Turbo-R, but they're not the same...
Most 1M x 4 bit DRAMs have type numbers ending in ...4400 (one easy source is really old PC memory modules). But there exist 

