Re: 8050 which will write but not format

From: Julian Perry <>
Date: Sun, 2 Dec 2012 10:23:20 +1100
Message-ID: <>
Hello Rob,

Sunday, December 2, 2012, 10:12:00 AM, you wrote:

>>> Well, I cranked the speed down to around -6ms to slow (I assume that's
>>> milliseconds per revolution) and it appears to format more - it got to
>>> around track 20 before barfing.
>> Hmm - so drive speed affects the problem.
> Possibly. The jury is still out on that one as it will occasionaly 
> format a few tracks even at the correct speed.

>> It couldn't be anything as silly as the test program not working
>> correctly on 50Hz mains?? (I can't see that the drive would have any
>> internal reference to mains frequency - the only CBM machine I know
>> that can do that is the C64)
>> Does the drive have a strobe disk on the spindle?
> Nope. The drive electronics are DC only - no 50hz source. There is a 
> strobe disk. Making a cheap strobe light is stilll on the tp-do list. 
> Unfortunately I don't have a working scope at the moment.

You don't need a fancy strobe - a fluorescent tube (Not a CF) in a
dark room should be quite
sufficient to get the stroboscopic effect - like the old western
movies, where the wooden cart wheels of the wagon seem to be
stationary, or spin backwards. There are usually two rings of strobe
marks - one for 50Hz, one for 60.
(often it's smeared a bit, because light from the different coloured phosphors in
the tube decay at slightly different rates)

>> Very weird.  I've a full dance card right now (don't we all) - but I'd
>> love to have a look at the ROM, and determine the formatting code on
>> the drive.. I'm sure there roms exist on the 'net.
> Right. I can see this becoming a 'mission' for me and an annoyance for
> my wife in the next week as I should be doing other things to prep for
> xmas. :-)
Oh, I know that feeling well :)


> Rob

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Best regards,

       Message was sent through the cbm-hackers mailing list
Received on 2012-12-02 00:00:37

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