"Ross Herbert" wrote in message
...
On Thu, 15 Sep 2005 01:56:12 GMT, "Bob Kos"
wrote:

Hi All:

I'm trying to repair a CDRW drive that is part of a Sony Laptop Computer.
The drive is a Panasonic / Matsu****a model UJDA730. It is a combo CD /
CDRW / DVDROM. The drive is totally dead. I have substituted a drive
into
the computer and it works fine. I have isolated the problem to the drive
itself. I took this drive apart and ran some voltage tests. Panasonic
was
nice enough to silkscreen voltages on the board in various places and
those
voltages are in place except for one. The component pointed out in the
photo linked below has 5v on one end but 0v on the other end. The sister
part to it has voltage at both ends. Resistance testing shows my mystery
part having 420K ohms or therebouts, the sister part has .4 ohms
resistance.

http://bkos.home.infionline.net/MysPart.jpg

My guess is that this part has an open or high resistance. My problem is
that I haven't a clue what it is. It looks like a very tiny coil. But I
could be wrong about that.

Does anybody know what this part is? Any thoughts on the markings - '270
M23' ? Any idea where to get one? Are they difficult to change? It
appears as if the entire component is soldered to the board, not just the
corners.

I'd hate to trash this drive if it is repairable. Even used they cost
over
$30 and what will I get for that money? New is out of the question -
$150
or therebouts.

Any help or advice would be appreciated.



It definitely is an inductor (coil). Could be associated with the
power supply part going by the type and size of adjacent components.

These items are relatively easy to remove even without specialised smd
tools. Use a fine conical tip soldering iron and remove as much solder
as possible using solder wick or a vacuum pump taking care not to
apply heat for too long. Even though the inductor is less sensitive to
heat applying the tip for too long may damage the pcb tracks. Now
apply heat to one corner at a time and while the solder is molten
carefully prise up that corner with a small flat bladed screwdriver or
knife. Do the same to the other corner. It may take a couple of goes
if you are to avoid ripping the copper tracks off the pcb.

Since the item is a coil you may find that one end has simply become
disconnected where it terminates on the solder pad and you can repair
it. If not then a new inductor will be required. Looks like it could
be a 270uH to me.


Thanks for your reply. Your information is good. Unfortunately for me, I
was not able to save the inductor. It had some kind of corrosion or
reaction that weakened the wire and allowed it to open. The part is
destroyed. Now I must try to locate a replacement. Any recommendations on
where to go? Any ideas on a substitute item that will work? I cannot find
anything even closely resembling what I have at any source close to me (
parts chassis, catalogs, etc.). FWIW, this inductor has a solid ferrite
bobbin. Again, any help would be appreciated.