This TV had hiccups though all of the usual things checked OK. I was suspicious of a little three terminal device that a lot of sets use, but I didn't have one on hand to try. This device comes in various voltage ratings, is connected from the main (140 volt in this case) rail to deck, and it's third terminal's output is fed through an optocoupler back into the primary chopper circuit to provide information which allows regulation of the power supply to 140 volts.. The devices are available in voltages from 90 to 140. Mine was SE140N. Or at least it could have been, and that's what I replaced it with to fix the set. The one used in this set was actually a thick film assembly marked DP142, but it can be replaced by an SE140, it even shows the option in the service manual. But it was faulty, and I don't yet know how to check them, except in a 140 volt circuit. So it can be hard to find the fault, although it is a common problem.
Topic: NEC CP-785A Chassis with Hiccups (Read 4542 times)