[Coco] Did this really happen?

[Arthur Flexser]

Oops, Basic may mess with address 0, safer if you try it with $72000 and
$62000 instead.

Art

On Sun, Sep 5, 2021 at 10:28 PM Arthur Flexser <flexser at fiu.edu> wrote:

> 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
>>
>>
>> --
>> Coco mailing list
>> Coco at maltedmedia.com
>> https://pairlist5.pair.net/mailman/listinfo/coco
>>
>