[Coco] CoCo 1 64K upgrade failed :(.

[Mike Pepe]

Phill Harvey-Smith wrote:

> Mike Pepe wrote:

>> Phill Harvey-Smith wrote:

>>> Did you check the voltage pins with a meter before plugging in the 

>>> 64K rams, IIRC 4116s (which would be in for the 16K), use +5V, +12V, 

>>> and -5V

>>> applying the +12/-5 to the 4164s will almost cirtainly fry them 

>>> (managed to do this by mistake once, and the magic smoke definatly 

>>> exscaped :( ).

>>

>> I'm reasonably certain that the 4116's are +5V only. I know for sure 

>> the 4K RAMs also needed -5 & +12V

> 

> Nope, not acording to the data sheets I have and :-

> 

> http://www.cbmhardware.de/mosic/ram4108.php

> 

> That's IIRc what some of the jumpers do, re-route the voltages.

> 

> Cheers.

> 

> Phill.

> 


That's good to know. I'll be careful if I do the upgrade then. I 
remember seeing some home-upgraded D boards that bent the pins out of 
the sockets and had them connected via flying leads- probably because 
the jumpers weren't appropriate for 4164's at all.