Originally posted by Steven7 Regards the trigger voltage, I can't recall the exact value but it is between 8.5 and 10v. I've had no problems using this on a K10d. The 6-volt 'limit' is very conservative.
Same here. My Vivitar 3500 and 283 both measure 9.4V. I've been using them with my K10D without any problem. I've read somewhere (the source seems to be credible) that the limit of the current batch of Pentax DSLRs is 25V.
Originally posted by Steven7 The pre-flash you are getting is the red-eye reduction, and of course the flash can't recharge quick enough to re-trigger.
I think you got it. I didn't think of the silly red-eye reduction setting, simply because I've never used it, even with P&S. It is too annoying.
In light of this, I don't think the OP needs to do any modification to the flash. My Vivitar 3500 is dedicated to Minolta (DM/M on the module) so I did remove the dedicated data pin. But the OP has the Pentax module (DM/P) so it's OK there.