[comp.sys.cbm] C64 Disk Drive Error Light Question

TESSIER@YaleVM.YCC.Yale.Edu (08/08/90)

I have an old (8 years?) disk drive on which the error light is blinking at
power up.  I have been unable to clear it or determine its cause... any ideas?
 
thanks in advance.

shad04@ccu.umanitoba.ca (Dan Fandrich) (08/08/90)

In article <90219.131526TESSIER@YaleVM.YCC.Yale.Edu> TESSIER@YaleVM.YCC.Yale.Edu writes:
>I have an old (8 years?) disk drive on which the error light is blinking at
>power up.  I have been unable to clear it or determine its cause... any ideas?

Sounds to me like your ROM is gone.  Most of that excruciatingly long delay
at powerup is the drive calculating a checksum of the ROMs.  If it detects
an error, it's twinkle time.  Try swapping ROMs with a friend's drive and
see if things start working again.

>>> Dan
-- 
CDNnet:     shad04@ccu.umanitoba.ca
Compu$erve: 72365,306
FidoNet:    Dan Fandrich at 1:153/511.1

fred@cbmvax.commodore.com (Fred Bowen) (08/17/90)

In article <1990Aug8.054152.14522@ccu.umanitoba.ca> Dan Fandrich writes:
>>I have an old (8 years?) disk drive on which the error light is blinking at
>>power up.  I have been unable to clear it or determine its cause... any ideas?
>
>Sounds to me like your ROM is gone.  Most of that excruciatingly long delay
>at powerup is the drive calculating a checksum of the ROMs.  If it detects
>an error, it's twinkle time.  Try swapping ROMs with a friend's drive and
>see if things start working again.

Which drive?  I'll assume it's a 1541 (eight years sounds about right :-)
The 1541 powerup diagnostic blinks a pattern to indicate what's bothering it:

			1 blink	= RAM page zero bad
			2	= ROM at $C000 bad
			3	= ROM at $E000 bad
			4	= RAM bad

Use this info as a guide- obviously if the ROM containing the diagnostic is bad,
or the RAM it tallies the checksum in is bad, who knows what kind of blinks
you'd see (the diagnostic is in the $E000 ROM).  If you need to replace a ROM,
it'd be a good time to consider something like JiffyDOS (check the magazines-
I'm not a Jiffy customer or user, personally).


-- 
Fred Bowen			uucp:	{uunet|rutgers|pyramid}!cbmvax!fred
				domain:	fred@cbmvax.commodore.com
				tele:	215 431-9100

Commodore Electronics, Ltd.,  1200 Wilson Drive,  West Chester,  PA,  19380