I have a problem with USB connection to external Hard Disks. 

The problem is that after some time - I don't know exactly how long, maybe an hour or two, maybe VARIABLE - the USB connection is dropped/disconnected and the HD disappears from the system - My Computer, DiskManagement, Device Manager.  Sometimes it spontaneously reconnects, and autoplay starts (this may have something with my activating the PC, as I am always absent when connection is dropped. I need to move & click the wireless USB mouse to wake that up on returning), sometimes not.  Sometimes the power to the disk needs removing and reconnecting to get it recognized again, after which it behaves 'normally' (if I am lucky) . 

It occurs in Windows XP (have not checked other O/S).  I have set Power Options to 'Always On'

I am using a 'universal'  (SATA or PATA / 2.5 or 3.5 in any combination, various connectors) to USB adapter, and either an external PSU or connecting power from the computer's own PSU.
The problem occurs on two separate computers, with different adapters, cables etc).

I am testing a number of hard disks, using typically SeaTools for Windows and HDTune; scans with these may take many hours, too long to sit by the PC and wait; that is why I have no data on how long before the connection drops out.  It's pretty annoying to find a 500GB disk that was ok with SeaTools suddenly become continuously half full of bad blocks with HDTune; you don't know where you are after 24 hrs of testing.  The only indication given by the testing programs unless you restart them is the sudden occurrence of bad blocks/sectors; they keep scanning even after the disk isn't there.

This problem doesn't seem to happen with my WD Elements, which I use for back up which sometimes takes a while.

Anyone explain or/and offer a (simple !) fix please ?  This case is slightly different to others I have read about on the internet (and in this forum)

Dumb_Question
28.March.2015

Compaq Presario S5160UK DT261A under XP/SP3
Processor - Celeron 2.7 GHz
Motherboard - MSI MS-6577 v2.1
RAM - 2GB (1GB +1GB max) DDR PC2700
PSU - OCZ 500W
Nvidia GeForce 6800GT graphics card in AGP slotYou have the problem on two computers. THEREFORE it is hardware. Replace the adapter. And the power supply.Thank you for your answer Geek-9pm. 

I have not forgotten this problem, it has not gone away.

I plan to look into the matter further in the next few days; I have another adapter of the same design and a 2.5" SATA<->USB enclosure to try out

Dumb_Question
2.April.2015

Compaq Presario S5160UK DT261A under XP/SP3
Processor - Celeron 2.7 GHz
Motherboard - MSI MS-6577 v2.1
RAM - 2GB (1GB +1GB max) DDR PC2700
PSU - OCZ 500W
Nvidia GeForce 6800GT graphics card in AGP slot

From my mishaps I have learned that s few adapters are not reliable. Often there is a power issue. The USB ports and a PC are meant to stop when something goes wrong. Often it is power related.

Also, some of the power adapters for hard drives overheat. You can tell by unplugging the AC cord for a few minuteness and try again. Sometimes that solves the problem. So I stop using the weak power supply.
 Hi Geek-9pm

Further to my experiences...

I too suspected a power issue (IDK why, maybe it's because I used to operate on Energy Star; now I use Always On for disk testing).  That's why I went over to using the internal PSU from my PC for power, it has (like the original separate PSU) both 5V and 12V when needed (for both 3.5"/2.5" as needed).  The disk is always powered through a separate power source (not USB 5V) connector to a Molex -> SATA power adapter cable (passive, wires only).  Power isn't the issue. 

The original PSU supplied does get hot, I thought it might be a fire hazard, but no fires yet.  After 12 months of operation on the PC with case closed (no access to internal PSU) one gave up on me...this is now in the pile of 'things to investigate'

I thought it might be a design issue in the SATA/PATA<->USB adapter, that's why I am GOING to test with the enclosure/built-in SATA only <-> USB adapter.

For various reasons (not all of which are simple USB drop) the time for USB to drop out varies, from short (2 minutes) to...never

Dumb_Question
3.April.2015a picture of the adapters I am using (an attachment) - I think many adapters contain the same chip which does the conversion (with an oscillator)

No power cable is attached - that is separate.
The USB I/O is clear; 44-pin and 50-pin PATA I/O (for 3.5" and 2.5" disks) are visible along two long edges, SATA I/O for data cable you can just make out on the face near the bottom

Dumb_Question
3.April.2003



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