[Coco] CoCo 2 64K upgrade blues

[Dave Philipsen]

So now that you have given more specific information about pin 1 it is 
easy to see that you should pull/bend pin 1 so that it resides outside 
of the socket.  And the best would be to tie pin 1 of each chip to pin 
16 (which is ground) of that chip. It would technically be better than 
tying all of the pins together and then to ground although that would 
probably work too.  The idea of avoiding sporadic reads or writes is a 
valid one but still has nothing to do with whether the computer is 
'used' or not.  Maybe I am misinterpreting your use of the word 'used'.

Leaving pin 1 in the socket (and therefore tied to Vcc) is probably ok 
too but the preferred method is as mentioned above.

Dave


On 8/5/2017 9:38 AM, Carlos Camacho wrote:
>> What does the machine being 'used' have to do with anything?
> To avoid any sporadic reads or writes
>
>> I suppose the best way would be to tie Pin 1 to the ground of the chip
> which is pin >16. If you are saying that the machine runs ok with Pin 1
> left floating but it does not
>> when you tie it low that's kind of strange.
> Yes, that is the situation. If I just install the RAM and do nothing, it
> boots fine.
> If I try any type of grounding on PIN 1, it won't boot. Take off the
> grounding and it boots.
>
>> If you haven't lifted the pins out of their sockets and are
>> connecting them all to GND then you could be shorting out the whole system
> It seems like the way you describe.
>
>> If you haven't lifted the pins out of their sockets and are
>> connecting them all to GND then you could be shorting out the whole system
> After trying to ground PIN 1 two ways and not booting, and doing nothing
> and it boots fine, what you are saying gels.
>
>> Did you pull the pins 1 out of the socket before grounding?  If not I
> suspect the
>> problem isn't the grounding of pin 1 but the shorting of whatever signal
> is on pin 1
>> of the sockets to ground.
> Aha.. interesting. I did not pull Pin 1 out of the socket. So you are
> saying I should bend all the PIN 1s so they don't go into the sockets? If I
> follow this advice, after bending PIN 1 out of the sockets, then the next
> step is? Connect all the PIN 1s together and then go to ground? If so, what
> is the recommended place on motherboard to ground to?
>
> Thanks everyone for various advice. I haven't done a memory upgrade in 34
> years. I find my lack of knowledge disturbing as Darth would say. ;-)
>
> Carlos Camacho
>
>
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
> Virus-free.
> www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=link>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>