[Coco] RS-232 pak problem - possible answer

Robert Gault robert.gault at worldnet.att.net
Thu May 20 14:34:26 EDT 2004

James Dessart wrote:

> Well, it looks like I might have found the culprit... some of the traces 
> on the connector are cut. I think they're the high address lines, but 
> I'm not sure. Could someone with a revision A RS-232 pak tell me what 
> the connections look like for the 3 left-most traces on the card edge, 
> on the bottom side of the pak look like?
> It looks like someone has just taken an exacto to those traces... it's a 
> pretty deep gouge, too. Looks like this for me:
> Underside of pak, card edge side:
> [ /||||||||||||||||||||\ ] <- traces
> [\/--- <- gouge        \/]
> Thanks,
> James
If I am reading your diagram correctly, these traces are all even and 
run from left to right 2-40. The traces in question would be:
pin	function
2	NC		-12v on Coco1 or 2
4	NMI		non-maskable IRQ; cut on my card
6	E clock
8	CART		IRQ line
10-16	CPU data
18	R/W  CPU
20-30	CPU address
32	CTS		cartridge select
34	ground
36	SCS		not used on my card
38	CPU address
40	SLEND		not used on my card

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