My pentax 3.0 digital camera is not picking up reds properly. a few years old and well used - worth repairing?

pics seem to be short of red - seen initially on lcd before shot - and verifiable by taking pics of range of colours

You MIGHT have a color balance option somewhere in your menu system. Look around for this. If you don't, I'd agree with cwolfsheep's suggestion to just buy a new camera. The A530 is nice, but the A630 is nicer...

Choose from among these:

http://www.dpreview.com/reviews/compare_...

Most digital cameras can be found online now for $100-150 at the 4.0-6.0 range. I'm having good luck with a Canon A520.

It is time to put the poor thing out of its misery.
Or convert everything to b&w.
The good news: Digital cameras have improved oodles in the last few years. Your new model will undoubtably have more features, more pixels, and will take better pictures faster than the old. And will probably cost less to boot!