Re: C128 'VIC tower' mod board

From: marko.makela_at_iki.fi Date: Mon, 20 Jul 2020 18:58:25 +0300 Message-ID: <20200720155825.GA1647209_at_jyty>

On Sun, Jul 19, 2020 at 08:58:15PM +0200, Gerrit Heitsch wrote:
>I have never seen any 64Kx1 DRAM slower than 200ns though.

My oldest PAL C64 is equipped with 350ns DRAM chips and a VIC-II in 
ceramic case. So, they do exist.

>Maybe they thought they need it but then found out they don't and 
>omitted the circuit on the newer revision? I mean the 250466 board for 
>the C64 has an unused place U11 for a 74LS139 next to the RAMs. It will 
>work fine with U11 populated and J3 cut or U11 empty and J3 closed. If 
>I remember right, the purpose of U11 is to make R/W go HIGH as soon as 
>PHI0 goes down.

Should I check it on that board?

	Marko