Re: upgrading CBM-3040?

From: Mike Stein <*mhs.stein_at_gmail.com*> Date: Mon, 13 Nov 2017 13:37:22 -0500 Message-ID: <A9DDBF3966F84F13864EA9C3451DE2F8@310e2> · mhs.stein_at_gmail.com

----- Original Message ----- 
From: "Francesco Messineo" <francesco.messineo@gmail.com>
To: <cbm-hackers@musoftware.de>
Sent: Monday, November 13, 2017 11:33 AM
Subject: Re: upgrading CBM-3040?


> On Mon, Nov 13, 2017 at 3:17 PM, william degnan <billdegnan@gmail.com> wrote:
>> Yes.  There was an upgrade kit.  If you can find the chips or steal them
>> from a 4040 drive here is what I found:
>>
>> Replace the 6530 with the CBM chip 901466-04
>> UL1 gets a 901468-12
>> UJ1 gets a 901468-11  (take from 4040 UK1)
>> UH1 gets a 901468-13
> 
> ok, the last three chips can be 2532 EPROMs with the right content, no
> problems here.
> Looking at the schematics, it seems that the 6530's ROM is selected by
> /RS0 only, so in theory, I could
> make an adapter to tie /RS0 of the original 6530 high, and use the
> select signal to enable another external EPROM for the new
> code. The rest of the 6530 should continue to work as expected, am I right?
---
Some drives use 2332s with an active-high chip enable and it looks like that's the case with the 2/3/4040 drives' CS2, so you might also have to add an inverter in order to use 2532s.

m

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