Author:  Mike Boesen  

Last updated: 1 December 2006

1.  Background

In recent days a number of PCUG members have reported intermittent problems with hard drives and optical drives (CD or DVD drives), with some problems involving spontaneous reboots.  Some of these problems appear to have been due to loose or faulty power connectors.  This risk of this type of problem is compounded if a hard drive is in a caddy that can be inserted into a cradle located in one of the optical drive bays, because there are two power connectors per drive: 

With permanently mounted hard drives and optical drives, there is usually only one plug involved per drive, except where a power lead has been extended with another power lead.

Irrespective of whether or not your hard drives are mounted internally or in caddies, spontaneous reboots and intermittent problems with hard drives and also with optical drives may be due to loose or faulty power sockets.   So if you are eperiencing such problems it it worth while checking the condition of the connectors that provide power to your hard drive/s and optical drive/s.

Checking power connectors

If you are inspecting your power connectors, check for these two things:

Spread sleeves

The most frequent bad connection problem is spread sleeves in the 4-sleeve plug.  The sleeves are split metal cylinders with an inside diameter a bit smaller than 2 mm.   They are designed to fit tightly over the four pins in the receiving socket.  The diameter of the pins are a bit over 2 mm.  This is a picture of a plug (in reasonable condition):


If the 4-sleeve plug is removed at an angle or inserted at an angle, or extracted and inserted often, the sleeves can be easily spread.  The spread increases with frequent extractions and insertions.  This is a picture of plug with a sleeve spread to show you what a defective one can look like - the one on the right is definitely sick and the second from the right looks marginal.  The third from the right looks OK.


To close up a sleeve, insert a small jeweller's screwdriver with a 2 mm wide blade (or maybe a pointed nail file) between the outside of the sleeve and the wall of the hole in the plastic case.  Lever the metal side of the sleeve inwards so as to close the gap in the sleeve. 


Do that both sides of the gap.  Achieve a nice round result if possible.  The sleeve material is relatively malleable, so don't worry if you need to do a bit of fiddling to get the gap closed up to the desired amount and the sleeve nicely rounded.   A good idea of the desirable gap can be obtained by looking at any of the unused 4-sleeve plugs that may be inside your computer.  Or have a look at a 4-sleeve plug that is extracted and inserted infrequently and/or which is hard to extract from its socket.  After adjustment, the cylinder on the right should be closed up to look like this:


I need to close up a tad the second sleeve from the right, too.  After closing up any errant sleeves, see how the plug fits - it should require a fair bit of force to insert and to extract.  If it slips in and out quite easily, the sleeve gaps are still too big.

Incorrectly inserted IDE/UATA cables

Another possible cause of erratic behaviour of a hard drive or optical drive is the IDE or UATA cable's socket not being inserted all the way.  This is the socket (or sockets) on the cable that runs from the motherboard to the rear of the drive/s (or rear of the cradle for the caddy if you have one).  So while you are checking the power cable, make sure that all cable headers (rectangular sockets with 39 holes) are pushed fully onto the 39 pin plug at the back of the drive (or at the rear of the caddy's cradle).  Do the same check for the other end of the cable where it connects to the motherboard.

Caddy and cradle mating lands that are too low in profile

For folk with cradle/caddy arrangements, there is yet another possible cause of erratic behaviour for a drive in a caddy.  I have checked out a number of systems on which there was unreliable transfer of data and the hard drive in a caddy was operated slowly.  The problems were caused by inadequate mating of the lands (flat raised metal band usually gold plated) on the big 50-land plug at the outside rear of the caddy with the big 50-land socket at the inside rear of the cradle.  With these problem PCs the caddy seemed to slip into the cradle with very little insertion force being applied and I became concerned that some of the caddy and cradle lands were not always touching .  After I fine tuned the lands in the caddies' sockets, the problems vanished and have not reoccurred.  To see how to do that tuning read section 4 of my article on caddy fixes which is accessible through my web site: http://www.pcug.org.au/~boesen/ 

Check the functioning of the hard drive after fixing anything

If you have had an erratically behaving hard drive and you undertake any fixes for cables and sockets, you should then run the Windows application CHKDSK.  The chances are that erratic drive behaviour will create bad sectors on your hard drive.  To run CHKDSK is easy and is explained in this article of mine:


There are some other articles about PC stuff on my site here: http://www.pcug.org.au/boesen/ 

Mike Boesen