Hitachi 40HXC06U (17IPS19-4)

[speedypro]

Got here another cheap tv in for repair. On inspection, I have notices the fuse in the lead was blown, fuse on main power board was blown (burnt) and two short diodes. Those diodes where RL207 (1000v 2A). I have replaced this with 1000v 3a. The Tv now has power. Pressed the power button: red light flashes, then blue etc then goes back to red. Is it because I used a higher rated diode or something else is still damaged? All other transistors tested ok.

Pics:



Red circle shows where the original diodes (RL207 @ 1000v 2a)

Yellow is the replacement fuse.

Back:



Red in the above is the replacement diodes (IN5408 @ 1000v 3a) Pins too big to goes in from the top so I have placed them at the back.

[CapLeaker]

Re: Hitachi 40HXC06U (17IPS19-4)

No... that has nothing to do with the higher rated diode. There is something else bad. You have to test the PSU and see what is actually happening.
Does the PFC work? Are all the secondary voltages up etc.
Since it is a Vestel piece of junk, I would surely look at the rectifier diodes at the secondary.

[speedypro]

Re: Hitachi 40HXC06U (17IPS19-4)

No... that has nothing to do with the higher rated diode. There is something else bad. You have to test the PSU and see what is actually happening.
Does the PFC work? Are all the secondary voltages up etc.
Since it is a Vestel piece of junk, I would surely look at the rectifier diodes at the secondary.

Thanks. How to the PFC? Im also an electrican and PFC means Perspective Fault Current lol.

[CapLeaker]

Re: Hitachi 40HXC06U (17IPS19-4)

PFC here is Power Factor Correction. If the PFC works, you should have more than 360V DC on the main filter cap on the primary side of the PSU. Be careful around the primary side of the PSU. You may force the PSU on with all boards disconnected and see what that does.

[budm]

Re: Hitachi 40HXC06U (17IPS19-4)

This power supply/LED driver board does not have PFC.
Can you retake the pictures (of top and bottom side again? The pictures are cutoff so it does not show the whole board so that makes it hard for me to trace out the board.

[speedypro]

Re: Hitachi 40HXC06U (17IPS19-4)

[budm]

Re: Hitachi 40HXC06U (17IPS19-4)

Bottom side picture too please.

[speedypro]

Re: Hitachi 40HXC06U (17IPS19-4)

[budm]

Re: Hitachi 40HXC06U (17IPS19-4)

The 3A rating for those two main AC rectifiers are fine and are working because the standby power supply is working and feeding the Voltage to run the main board otherwise you will not have any indicator lights.
The problem right now is that the connector between the min board and the power supply board do not have any labels for each pins to tell us the function of each pin. We need to find out if the main board is sending the PS-ON to turn on the rest of the power supply or not, same for the BL-ON to turn on the backlights circuit.
Please also upload the pictures of the whole back side of the TV so I can see how all the boards are connected together.

[speedypro]

Re: Hitachi 40HXC06U (17IPS19-4)

Thanks, budm.

I've left work so tomorrow I'll upload more pictures.

[speedypro]

Re: Hitachi 40HXC06U (17IPS19-4)

Sorry for the delay. Here are two more pictures:

[neodark]

Re: Hitachi 40HXC06U (17IPS19-4)

interesting

[ReeceyBurger123]

Re: Hitachi 40HXC06U (17IPS19-4)

Cause of this is 12v output diode shorting, sometimes it will pull too much current through the transistor. Short that out which then blows the controller for it, blows the rectifier diodes and the fuse.