Originally posted by J.Scott Better yet, invest in a small (cheap) Sekonic light meter. Keep it in your camera bag at all times.
+1 regarding the light meter. KEH has a couple of selenium Sekonics in EX condition for under $30 USD.
Comparison to another camera is a good idea. Use a blank white wall with even lighting at about 10 feet and with focus set to infinity. If possible, use the same lens for both cameras and the same exposure mode. Check at the extremes and mid-point for ASA/ISO settings as well as the full range of lens apertures. Do not compare to a Pentax dSLR metering in green button mode.
My suggestion regarding the repair place was in the interest in getting a diagnosis along with a bid. They have a standardized light source. Actual choice of a repairman is another matter. Conventional wisdom is to send your Pentax to Eric, but no sense doing so if there is nothing that needs fixing.
Steve
(Has a Gossen Luna Lux due to arrive any day now...)