To get to one of the other values from 500 the three playfield reels need to line up in specific ways as described by this part of the schematic:
Klondike 3000 pt relay (resized).jpg
For example the paths to the 3000 point relay are shown in red. To get the 3000 point relay to fire the left reel must be in positions 4, 6, 8 or 10 (unless the Bar relay is on), the center reel must be in positions 3 or 5 and the right reel must be in positions 3 or 5. If you're always at 500 I'd examine the playfield reels. There will be wipers and contact boards that may need a good cleaning.

/Mark

The best cleaner in this case would probably be a metal polish for the circuit board and contact ring, but that would probably require disassembly of the reel. I think this is the reel used in Klondike although the circuit board will have a different pattern:
Williams 1970 catalog score reel (resized).jpg
Another possibility is that there's a bad joint or connection or contact ring on one of the score reels so that there's never a good path through it. One way to find something like that is to shut off the power and clip one multimeter probe onto the 3000 point relay coil solder lug with the green-white wire and the other probe to the yellow-blue wire between the left and center reels. Set the meter on the lowest resistance setting and manually advance the right reel. You should find several positions where the resistance through the reel drops to an ohm or less. Repeat that test for the other wires between the two reels (yellow-red, yellow-orange, yellow-green). And then test the other two reels the same way. Each time you should find a few paths through the reel you're testing.

Hello, Mark and mrbanjo,

i have the same problem on my Williams jackpot of 71.

is mijn pinball met de zelfde techbiek uitgevoerd??