For anybody interested in making this DP501 divide by sixteen prescaler work,
here's my best fix:
The best match is to a DC509/510 or DC5009/5010 counter which has a single rear pin designated as PreSCALE-NOT (meaning active LOW). This changes the internal count by having the microprocessor multiply the count value by 16, and gives a usable direct reading result. To make that work, add these two wires between the two modules:
Pin 14B to Pin 14B (Prescale-NOT)
Pin 15A to Pin 15A (Logic ground) (to insure clean operation between modules)
-->>>this is symmetrical, either unit can be in either slot.
I used a TM502A and tacked some wires on, but any TM500 frame bigger than a TM501 will work. This combination can also be achieved with a DC503A, but it's messy, with more lines. I didn't bother, as I had an un-tasked DC509 that wanted to be used in this way. Any other Tek counter will require a calculator to get usable results.
Documentation for this is very modest, I had to go to Hakan for the final confirmation. I found the 14B line in the DC509 manual, but had no idea where it went on the DP501. he cleared that up for me.
Too bad the connectors don't line up and are too far apart to connect cleanly with just some adaptors. A short BNC jumper cable is needed to tie the counter input and prescale output together at the front. A very complex and costly way to get this level of counting today, but I had the stuff, so the goal was to get it running correctly. wahoo, baby...
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.