sad device - no support - no fix

[tedstruk]

A gift to me... A USB "versa drive" external hard drive. This device roars up to abut 7200rpm(I think its a 5400 device) with a whirring buzz that shakes the earth foundations in the desk....
Then it just is a do nothing app, and no drive appears in the drive list, and the entire thing was a waste of money time and effort to save store and keep your precious files...(kind of funny... but fairly expensive so don't laugh yet!)
tinker tinker and more tinker! (did I say thinker?)
installed the drive in a PC, works like a brand new drive... I wonder why?
and the board in the "VD" is small 1" x 3.5" has a meriad of great components...
mini fan
IDE buss
short power adapter - small factor to large factor
DC adapter port
mini power switch

onboard I found an induction coil on a toadstool that has a busted toadstill cap.... that is the top of the induction coil is missing about 1/3 of the top... broke off.

It has "220" written on the top of it. I wonder if this could be the problem ie. why the thing didn't work?
so much for valuable components!!! a little coil of expensive wire wrapped around a cheap core spool...

 

[kellys_eye]

As a stand-alone device the HDD interface takes either a DC input and will be required to 'develop' its own 5V and 12V supplies.

The coil (broken) will be part of the SMPS conversion to generate this missing supply and the broken ferrite former will be affecting the conversion process.

The '220' notification will refer to its value of 22μH and any suitable replacement will restore the supply and fix the drive operation. Just make sure the replacement inductor has the same thickness wiring wound - looks to be good for a couple of amps to me.

 

[tedstruk]

K. the coil sits on the opposite side, SMD, to a DC-DC buck converter chip..
http://www.alldatasheet.com/datasheet-pdf/pdf/87873/ANACHIP/AP1507-50D5.html
I wonder if the induction changed the operation of the chip and caused it to fail? I know that if I get my finger close to an EPROM that it goes all on... I think that coil carries alot more juice than my finger... maybe a repositioning is in order?

 

[kellys_eye]

Buck converter - this means a 12V supply to the board and 5V generated via that device.

The spec states an operating frequency of 150kHz and the change of inductance can have a significant effect.

http://uk.farnell.com/coilcraft/do3316p-223mld/inductor-pwr-22uh-2-7a-20-19mhz/dp/2287248

is but one of many potential replacements.

If you can find the broken off bit....... it's possible to super glue them back together with little harm.

 

[tedstruk]

How about a thinner wire .03mh inductor piggy back style on the busted toadstool?
looks neat!

 

[kellys_eye]

0.03mH = 30μH and still 50% off what the circuit is designed to use. Also you cannot 'parallel' them - if you stack 'em you must electrically disconnect the duff one.

Have you tested to see if the 12V and 5V lines are correct?

 

[tedstruk]

I was using a 12v supply I made out of a spare I had in the shop. I didn't check any voltages, and when I found the busted coil, I just pulled the drive and stuck it in a PC to see if it worked, I suppose I should change the coil, reinstall a drive put it back together and test it again... but they are obsolete, I can't even get a power supply for it.
It has a lot of nice components for my collection though... better keep it for later!

 

[tedstruk]

I pulled 3 wraps from the .03mH and got .02mh how about that?

 

[kellys_eye]

Should be ok- try it.