Brad Davis wrote:
> I wouldn't expect the interface to put in such an even (if random)
> dot pattern. I have no idea how XP might be at fault, but the one thing
> that would seem to be common is the XP driver for USB(1&2).
No such problems here with XP USB2 and scanners or anything else. If he's
tried different interfaces and scanners, it sounds like dirty/bad mains
supply or RFI, or low volts on the USB perhaps. Early VIA chipsets were
awful for this, they'd sag badly if asked to supply anything like the 500mA
USB is specced for, and some peripherals just wouldn't work at all. But
that will only apply if he's using USB hung off the PC's internal USB ports
(powered from the mobo). If he's using a PCI card with USB ports he'll have
to look deeper (and if he isn't, he should try one as a priority, as they
circumvent the mobo USB chipset's limitations).
It may also be worth trying the scanner hung off a *mains powered* USB2
hub, in case the power supply from the mobo chipset is dirty or failing.
Not all scanner drivers like hubs though, so this could create new
problems.
If none of that helps, I think he's going to have to
- try the scanner on a different PC in his home
- try the scanner on a different PC somewhere else
- try his PC and scanner somewhere else
- try the PC and scanner at home on a decent UPS
to establish whether it's the PC or his mains supply.
If it is his PC, and a PCI USB card doesn't fix it, I think he's then
looking at establishing whether it's the PSU or mobo, by substitution.
Check the voltages in the BIOS. A careful visual inspection of the mobo may
help pin it down. Look for leaking/bulging/corrosion-covered electrolytic
capacitors especially.
Regards
Tony Sleep -
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