hitachi p50h401 ton or logic controller short

[awyatt2]

Re: hitachi p50h401 ton or logic controller short

diodes are RSX201L-30TE25CT-ND used a smd component id chart to decipher. 50 is diode number 80 is date code. no light on screen whatever the 85 vc and vs are missing if no power no light. already tried buffers, ysus and zsus. the signal to start the ps screen is held down according to service manual the screen wont light if the logic or digital board is out if i plug the digital unit up to a known good logic board it shuts down the set. if the main dig board dosent fix it the display is bad. so where i'm at is wating on these .70 diodes to arrive and hitachi wants 4.00 each for the same thing. i get sound and the channels and input change checked with antenna and dvd player,component and hdmi so at least the input board works.

[cadiman]

Re: hitachi p50h401 ton or logic controller short

You have your hands full with this one. As I said these can be very hard to troubleshoot.

These tvs are really bad when the power supply has issues it can take out other boards and other boards can take out the power supply and so on.

If you have audio and can change inputs that is great. I would say you have two faulty boards here from my experience with these tvs.

I would replace the two 3300/100v caps on the power supply for sure. They have been bad on all 4 of p50h401 tvs I have worked on.

[awyatt2]

Re: hitachi p50h401 ton or logic controller short

yes, they were high esr on this one too. first thing i did was reolace them. the tcon is ok, the ps will start i think when it get the startup signal from the main i hope. if not it will be a screen issue. i am trying to find a good digital board within reason. find plenty for 150.00 dont know if its worth the money because i wont know if it is the display without it.

[awyatt2]

Re: hitachi p50h401 ton or logic controller short

any way to test display to see if its shorted with a meter on this set? cheapest digital board is well over 100 and if the display is shorted it's not worth spending any money on

[awyatt2]

Re: hitachi p50h401 ton or logic controller short

update, i have totally checked power supply, working fine all voltages up and where they are supposed to be. the digital board seems to be at fault. anyone know of a way to get the screen to light as a test to see of it works before i spend 150 on a new digital board?the power supply required two return voltages of 5.1vdc to get vs and va up. they will hold with as low as .2 amp on the return signal line.