1 Nov
2009
1 Nov
'09
9:43 a.m.
On 31 Oct 2009 at 21:03, Steven Hirsch wrote:
- The unit has a 7812 (12V) 3-terminal regulator hung
off what would
normally be the +12V line of the molex connector for, e.g. a 5.25"
floppy drive. That input goes through a 100ohm 5W resistor before
hitting the regulator. With 12V applied the drive, I see only 9.2V at
the input to the regulator and approx. 7V on the other side. Sure
_looks_ like maybe it's supposed to see +24V at the top of that
resistor, doesn't it?
This drive sounds a *lot* like the Tandon 848, which also uses a 7812
to drop the +24 to +12. There's also an on-board jumper around the
7812 that allows the drive to work on +12 instead of +24.
There's a schematic in the TM848 product spec on bitsavers.
--Chuck