Author: GND. (webcacheW01b.cache.pol.co.uk)
Date: 03-18-2002 14:59
Thanks for the reply....
>Have you checked the line with a multimeter
>or something, to see if it changes at all?
ive got two drives that I have tested. One from a mega ste which changes between 4.9v adn 4.7v for the different densities. the other one seems to just float at 1.8v and not change at all...
>Some outputs from a drive may be open-
>collector type, so maybe you will have to
>add a simple pull-up (or -down?) resistor?
>Thatīs all I can think of for the moment...
could be, looking at the megaste circuit, theres no pullups on the line, but i suppose they could be in that PAL it connects to...
>Oh yes, some drives doesnīt even have a
>HD/DD switch, but since you have tried with
>some other drives, then that canīt be the
>problem...
I think my other test drive has this problem, the line state never changes.
>Tried with a buffer? The signal may be too
>weak. Sometimes a buffer with a schmitt-
>trigger input can do it.
At the moment its going into 2 inputs on a NAND gate on a 74ALS00. Ill see if I can find (amongst my junk) a buffer to put it through..
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