11 Mar
2005
11 Mar
'05
10:44 a.m.
From: "Michael Sokolov" <msokolov at ivan.harhan.org>
Sent: Friday, March 11, 2005 12:25 PM
Randy McLaughlin <cctalk at randy482.com>
wrote:
> I am 99.99% sure it changes the RPM, I have some TEAC 1.2's laying
around
> I'll plug one in and ground pin 2 to check
it.
>
> For the TEAC it is enabled via an option jumper, default is to ignore
it.
Changing the RPM is an option on SOME drives, and for PeeCees to work it
must be OFF. It is very useful for Classic Computers, though.
The high density select signal (pin 2) may or may not switch RPM, but it
always switches the write current. Writing on HD media with DD write
current
will produce no effect (the field is too weak to
affect the media), while
writing on DD media with HD write current will magnetise the media so
strongly that it'll be impossible to rewrite and unusable until you
bulk-erase it. So pin 2 MUST always select the correct write current for
the media type.
3.5" drives use the media type hole instead to select the correct write
current. Those who punch or cover that hole to magically "change" the
media type get what they deserve.
MS
No, I have refered to the TEAC site and to WDC:
WDC referes to pin 2 as speed select, their controller can be used with
either single speed or dual speed 1.2mb drives:
http://www.wdc.com/en/library/legacy/controllerboards/1006mm1.pdf
TEAC specifically stated that pin 2 is default to ignore, the I strap is
used to enable speed change:
http://www.teac.com/DSPD/pdf/5fd0050a.pdf
Randy
www.s100-manuals.com