****After many hours of studying the circuit and with the help of
everyone here, the ps problem has been SOLVED.
It was R907 o/c, part of the current sense circuit of UC3842.
Many thanks to everyone involved in this project.



Jim Yanik wrote:
BigTom wrote in :


how can i fix a ticking smps on a mitac L1450PD
it uses a UC3842 controller CNX82A optocoupler and TL431A shunt.
there are four lines on this monitor, 150v 87v 24v 6.3v all reading low.
how do i find the line causing the problem?



ticking indicates the PS is trying to start,but tripping a protective
current limit.

I'd check for shorted diodes on the secondaries and use an ESR meter to
check the electrolytics.