My Scanjet 3500 F1 looses connection after some time (USB on OSX 10.14)

[Middachten]

My Scanjet Pro 3500 F1 can't be found by my iMac (OSX 10.14) after I've been away from the computer for some time.

Is is connected via the original USB cable. Initially it works after power up, but after some time the computer can't communicate with the scanner anymore.

I've tried:

• Re-installing HP easy start
• disconnecting/connecting the USB cable
• Try various other USB cables that are working on other devices
• power off/on
• use various pieces of software: Preview, Printer/Scanner app in Settings, VueScan Pro
• Test on the same computer using Parallels + Windows 10: scanner is recognised, I can choose to assign it to OSX or Windows and the HP ScanjetPro software works most of the time. But even under Windows the software sometimes says "I can't communicate with the scanner"

Can someone help to get this working properly?

Albert 

[Middachten · Accepted solution]

I haven't been able to get help on this.

The best the HP support line could come up with is: "it works under Windows so you Mac must be broken"

I've decided to return it. Which is a shame because this was the only machine that combined a duplex sheet-feeder scanner with a decent enough flatbed scanner for scanning photos 😞