1 Mar
2011
1 Mar
'11
4:19 p.m.
On 01/03/11 19:58, Tony Duell wrote:
AFAIK, SA801s have one PCB which includes the
read/write chain and
stepepr controlelr, etc. There is no spindle motor controller, of course.
Indeed. The one I saw had the wires hacked off at various points (!) and
the PCB was completely gone. Something like that is worth scrap value at
best...
I'd better expand on that last part becuase it may
affect you buying a
drive second-hand. Msot, (but not all) 8" drives have cpacitor-run AC
spindle motors. Their speed is therefor set by the mains frequency.
As you would expect with AC motors.
I ahve seen both 15V and 230V motors in SA800s. Both
will run off either
50Hz or 60Hz power, but turn at differnet speeds. You can use a
transfoemr to convert the voltage, but the speed is more of a problem.
I assume you meant "115V and 230V motors", because I've seen the SA800
spec sheet, and IIRC it doesn't mention a 15V motor. The 115V boxen are
usually 60Hz, the 230s are usually 50Hz.
This, of course, means precisely nothing if you've got a spare mains
transformer, a sine wave oscillator and a power amplifier. DIY mains
inverter anyone? :)
The official fix is a different motor pulley. Getting
one is aproblem. Of
coruse it's not hard to trun one if you haev a reasoanble workshop, but
rather hander if ytou ton't.
And the cheat is -- as I've said -- to make a homebrew sine or
modified-sine inverter. An even better way is to find a drive with a
DC-drive motor. For instance, the NEC FD1165 takes 24V and 5V in.
Direct-drive spindle motor with integrated (read: big and heavy)
flywheel and an optical-encoder speed controller. Very spiffy. It's
still a brushed motor though, and I'm hoping the brushes are in decent
nick (I'm betting they won't be easy to replace!)
I fear tracking down a 6-pin "Berg" power connector might be...
"interesting". The 4-pin (PC 3.5 FDD power connector) variant is widely
available, but the AMP part number I have for the 6-pin is showing as
"discontinued"... Urrgh...
--
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/