HP HW6515 and Tomtom 6--can't lock on to satellites

[rsg]

I have an HP iPaq HW6515 with builtin GPS antenna. I've had Tomtom 5 and upgraded to 6, and it had been working fine for years, but recently it stopped locking on to satellites, so I reset the Quick GPS Connection modules to factory presets, and it still wouldn't work so I hard reset and reinstalled Tomtom.
I found that it does pick up accurate GPS time (UTC) and after a few hours in the open it will pick up several satellites, but weakly (can't get enough for a fix).
Can anyone suggest anything?

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