B9180 carriage jam

Hi

I have a HP Photosmart Pro B9180 printer. It's about 18 months old, but
hasn't been used much.

Its developed a fault. When the printhead carriage moves to the right hand
side, it makes a loud noise, as if something has jammed, and the printer
comes up with the following error message:

"Service stall. Press OK to continue"

After pressing OK, it makes a loud clicking noise, and comes up with the
following error message:

"Carriage stall. Clear carriage obstruction and press OK to continue".

I've looked inside and I can't find any kind of obstruction. The carriage
bar is clean.

The problem only seems to occur when the carriage has moved over to the
right, but that area seems to be clean and free of obstructions.

I wish I'd bought that extended warranty now!

Any ideas?

Thanks

Pete