Overcurrent on USB device

[Genosse Brymbo]

I have a Seagate FreeAgent Go 500GB USB disk which has been plugged into a Technomate satellite receiver for a couple of years.  Recording to and playback from the device has been faultless.  I then plugged it into my Panasonic Viera TV and was able to select and play recordings made on the Technomate.  After a couple of days, on the nth time of use (n < 5), the TV complained "Overcurrent on USB device occurred.  Please remove the USB device, and switch off the TV by mains power switch."

I've searched a bit for an explanation on the WWW (aren't most other forums and forum software pants!) and don't really understand the responses, as far as they make sense.  The disk can only be powered through the USB connection; there is no provision for an external PSU.  I would welcome the thoughts of forumites with electronics know-how on two questions:

1. Is it safe to continue to use the USB disk and just "reset" it as in the on-screen instructions when it plays up?  I only have a few recordings left to watch.
2. I was considering in future using some sort of streaming media device which obtains power from the TV's USB port, like Roku.  Does the problem with the disk indicate that this may be problematic as well?

Note: I chose Ctrl-Alt-Del and not OT Knowledge for this post because it concerns computer hardware (well, isn't everything just a computer with different I/O devices these days?)

[Feanor]

Perhaps the current consumption of the HDD is marginal for what the TV can support.

Since the HDD can only get it's power over USB, then you might want to try a USB Y-cable, where one end plugs into the HDD, and the other end has 2 connectors: one for the TV for the data, and another to plug into a generic USB power source.  In this way, the TV does not have to power the HDD, the external PSU does.

Something like this:

https://www.amazon.co.uk/StarTech-feet-Cable-External-Drive-Black/dp/B003HHK576

( That's just the first hit I got when searching, as an example. Not a recommendation. )

I'd expect a streaming device to use less power than your HDD, so I would not expect that to be a problem unless the TV is faulty.

[Kim]

Conservative current limiting on proper USB host ports (rather than chargers, battery packs and the like) is normal and ordinary, and this is the sort of behaviour I'd expect from a PC (well, I wouldn't expect it to realise what the problem was and notify the user like that, just unceremoniously shut down the port until power-cycled).

Safe, yes.  This feature exists to prevent hardware damage.  But obviously disks disconnecting at random isn't very good for your data.

Why?  Probably one of:
-The disk is playing fast and loose with the USB spec and exceeding the rated current draw.
-The disk has drifted out of spec over time due to a marginal fault (sticky bearings, capacitor rot) and is exceeding the rated current draw.
-TV's 5V power supply isn't quite up to the job and is dropping voltage, triggering this protection.
-Nonspecific gremlins falsely triggering the overcurrent detection.

Further diagnostics: Voltage/current monitoring of the USB power that's fast enough to detect transients.  This isn't going to be fun if the fault takes days to recur.

Workaround: Provide the disk with power from an alternative source.  Typically, in the absence of provision for such on the drive itself, by inserting a powered USB hub between it and the telly.  Might not actually work if the TV's software isn't expecting there to be a hub in the chain.  Or you could molish a bodgy splitter cable to bring the 5V supply in from elsewhere while passing through the data..


ETA: Crosspost with Feanor

[fuaran]

2. I was considering in future using some sort of streaming media device which obtains power from the TV's USB port, like Roku.  Does the problem with the disk indicate that this may be problematic as well?

Just plug it into a mains adapter. Think most of these streaming devices include an adapter as standard now. Or any decent phone charger should work.
Powering it from the TV might work, might not.

[Genosse Brymbo]

Thanks very much for the quick and informative replies.  USB hard drive now plugged into craptop and using VLC to play videos recorded on the Technomate (queue WWW searching for why sound doesn't work, fscking computers).