Re: [tlug] Possibility to recover a hard disk by swapping control board

[PF2K-WLKN@example.com (Keith Wilkinson)]

Because it is hard to image a disk failing (frying) 
as a result of inadequate power supply, it would be 
interesting to research the drive case and drive on 
the Internet if you could provide maker and 
model no. for both case and drive. There may well 
be a history of problems. 

Modern 2.5" drives draw only about 1.5W during R/W. 
USB 2.0 is supposed to provide up to 500mA of current; 
500mA @ 5V is only 2.5W -- hardly enough for the drive 
to go up in flames. 

Maybe the two most likely failure mechanisms are :
(1) incompetent designers -- maybe connecting only 
one USB connector can result in reverse voltage 
being applied to a component, which then fails. 
(2) because of excess current/low voltage, 
drive motor fails to start.  Stalled drive 
motor draws high current which toasts the motor. 
Hard to imagine that only 2.5W could toast the 
motor -- but maybe the motor is fused on the 
drive or on the controller board to protect 
against this eventuality?  If that's the case, 
then replacing the fuse would be enough to fix 
the problem. 

< historical aside > 
The first 3.5" plated-media drives to appear 
in Hong Kong were 100MB Seagates.  They had 
stiction problems:  the head was parked on 
the platter, and could stick to it, preventing 
the motor from starting.  If you didn't notice 
this soon after turning on the power, the 
motor would be fried. I know somebody who 
purchased a Seagate in HK, then had it fail 
two weeks later from stiction. He flew back 
to HK (from Japan) to have it replaced under 
maker warranty -- and the replacement also 
failed within two weeks. I believe that 
soon after this Seagate was having trouble 
selling drives, so a scheme to ship bricks 
in hard drive boxes was concocted, to make 
it look to investors as if shipments were 
continuing as usual. I believe that some 
directors were fired when this was found 
out. Unfortunately I can't find this story 
on the web any more.