[Coco] Re: FD-502 controller problem

Phill Harvey-Smith afra at aurigae.demon.co.uk
Fri May 19 14:01:57 EDT 2006

Mike Pepe wrote:
> Charlie wrote:
>> Gene and Phil, Thank you for the replies!

Phill :)

>> It is not a cable / drive problem as switching to my Disto SC II 
>> everything
>> works fine.
>> It has to be something specific with the 502 controller.
> All the signals that run the drives are in a parallel bus configuration, 
> except for the drive select signals. If there were a major issue with 
> the controller it should affect all drives the same way.
> The only thing that would be worth trying would be to replace all the 
> 7406 (or 7416) chips on the controller and see if that helps. 

Yeah might be worth checking/changing them.

>								If not 
> maybe the big 373 latch chip has a bad output for drive 0's select line.

But wouldn't a bad drive select affect reading too ? I thought Charlie 
said that it would load games and stuff ok.


Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.

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