[Coco] Did this really happen?

[Arthur Flexser]

A quick check for 512K is to see if values poked in "ghost" to other
addresses that are $10000 different.  For example,

10 LPOKE &H70000, 111
20 LPOKE &H60000, 222
30 PRINT LPEEK(&H70000), LPEEK (&H60000)

If the values printed out by line 30 are both 222, you have 128K;  if they
are 111 and 222, you have 512K.

(This is off the top of my head, somebody please correct me if I've made a
mistake here.  It's been quite a few years.  Try it on your 128K CoCo as
well as the 512K (?) one to make sure this works properly.)

Art

On Sun, Sep 5, 2021 at 6:16 PM M. David Johnson <mdj at bds-soft.com> wrote:

> Before I get too excited, I'd like someone, more proficient than I, to
> confirm my apparent unexpected blessing.
>
> I just purchased two 128K CoCo 3's off of ebay.
>
> The first one worked fine. It said "128K Color Computer 3" on the top, but
> just to confirm, I took a flashlight and looked through the top slots. I
> read MCM41464P on one of the chips (a 64K x 4 RAM I believe, implying a
> total 128K x 8 memory).
>
> When the second one arrived, it also said "128K Color Computer 3" on the
> top. But it had something rattling around loose inside the case. When I
> opened it up I discovered that it had empty sockets where I expected the
> RAM
> chips to be. And the thing rattling around loose was an L-shaped board with
> sixteen MCM6256AP12 chips on it (each a 256K x 1 RAM I believe, implying a
> total of 512K x 8 memory).
>
> After I said a quick "Thank You, Lord" under my breath, I re-seated the
> board in the headers provided on the motherboard, and closed the CoCo back
> up, I plugged it in and it too worked fine.
>
> Have I judged correctly?
>
> And, could the CoCo 3 512K Memory Checker available on the CoCo Archive be
> used to double-confirm this?
>
> --
> M. David Johnson
> mdj at bds-soft.com
>
>
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