[Coco] Broken CC3

[Brian Goers]

George Ramsower wrote:
>
> Well, DARN!
<Stuff deleted>
For higher frequency noise, I would use a smaller cap. Like a 0.1uf 
cap.This should filter the 100kHz better. A 2200uf will fill in a 60HZ 
ripple and deliver a higher current, like from a power supply.
> The ripple from the head stepper in the disk drive is showing up on 
> the 5V line. I've buffered the 5V line with a 2200uf cap to the coco 
> and the problem persists. If I DIR 1, the coco will give an I/O 
> error(there is no drive 1). If I DIR to the drive that it does have, 
> the coco crashes.
>
What is the 5 Volt value when the drive is not running?
What is it when the drive runs?
If the volts are marginal the drive running my drop the value below 4.75V.

> It's odd that if the drive's motor isn't spinning, the coco doesn't 
> crash. I can still see the ripple from the head stepper on the 5V line 
> to the coco.
>
> I thought that perhaps when I typed DIR something was being introduced 
> to the memory that might be causing the crash, so I did a DSKINI(0) 
> and the coco crashes after only a few tracks.
>
> I'm wondering if perhaps there may be a bad cap somewhere on the coco.
Check its values DC and AC ripple.
>
> Ideas? Suggestions? I'm about to start looking for hair on my head to 
> pull out. This is exasperating.
>
> George
>
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>
Brian
-- 

Brian Goers
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