Hitachi LE65K6R9 has menu image but no backlights

[brucetv]

I did the flashlight test and when I press menu I can see the menu image but the backlights are not coming on. The power supply voltages look good at:
5VSB 5.155DCV
STB 4.544DCV
GND
GND
+5V 5.154DCV
GND
GND
12V 12.20DCV
12V 12.20DCV
What is the proper way to check this type of power supply for proper voltages for the led's? It's a power supply/inverter type and I noticed on CON2 it says GND ADJ BK with only ADJ and BK wired. Is that for checking Backlight voltages? Also CON4 has a GND V+. Should there be a voltage there in standby and startup? And it has 4 separate + - for I guess possibly 4 arrays to the backlights on CN 234 and 6. I have a Fluke 115 so do I use the negative probe on - and the positive probe on the + on each of the 4 to check to see what voltage it shows on each of the 4 to see if one has a super high or super low voltage compared to the other's to determine a possible short on one of the led's? And where on earth is the best place for Hitachi parts in the USA? It's not even a year old....what a shame I'm not the original owner and have a warranty. Thanks for the help forum.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

ADJ is the dimming command signal from the main board.
BK is the same as BL-ON, Backlights On, command signal from the main board, >2.5V = ON for the typical Voltage level, <1V = OFF.
So what DCV do you have on those pins?
We also need good clear straight shot pictures of the bottom side of the power supply/LED driver board to see how the backlights LEDs strings are connected together.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Thanks for the info BUDM
with the ground on chassis I get
ADJ 5.020
BK 4.734

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

Thanks for the info BUDM
with the ground on chassis I get
ADJ 5.020
BK 4.734

So you do have correct Voltages.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Here are some additional closeup pics

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

Second request.
I need good clear straight shot pictures of the bottom side of the board to be able to trace out the circuits.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

It seems all my voltages at the power supply are good and I get the same voltages at the main board connector so I know my cables are good but I'm wondering if there is a shorted led causing the backlights to come on. Can I put the negative and positive leads on those CON 2, 3,4, and 6 where those red and white wires go through the panel to the backlights and check to see if I have consistent voltages? Seems like I read somewhere in the forum that if you see one a lot lower or higher it can indicate a shorted led.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

It seems all my voltages at the power supply are good and I get the same voltages at the main board connector so I know my cables are good but I'm wondering if there is a shorted led causing the backlights to come on. Can I put the negative and positive leads on those CON 2, 3,4, and 6 where those red and white wires go through the panel to the backlights and check to see if I have consistent voltages? Seems like I read somewhere in the forum that if you see one a lot lower or higher it can indicate a shorted led.

OK, so I am not going to see the pictures of the bottom side of the board after two requests to be able to tell how the LED strings are being driven and how they are connected together.
Sorry, I am moving on other thread,

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Sorry it's a little late but I had to charge the batteries back up in the camera. Here is the pics of the underside of the Power Supply.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Here is another closer pic of the led strip connections underneath.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

TV is off, then leave the black probe on point 'E' and then put red probe on point 'A' and then turn on the TV to see how high the Voltage goes up to.
Turn TV off then move the red probe to point 'B', turn TV on and take the reading.
Do the same for point 'C', point 'D'.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

ok...I'll have those readings for you shortly. Thanks for the help.

[Alastair E]

Re: Hitachi LE65K6R9 has menu image but no backlights

EEe gads--What crap are Hitachi rebadging Now! (Beginning of the end for Hitachi in 1983 when they started rebadging Salora crud and carried on with Vestel turds today...

Looks like those cheapo Chinese cruddy things popular in smaller sizes sold here from supermarkets by oddball makes like UMC! All Utter Trash!...

Prolly a few LED's gone short and one (or two) gone open...

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

EEe gads--What crap are Hitachi rebadging Now! (Beginning of the end for Hitachi in 1983 when they started rebadging Salora crud and carried on with Vestel turds today...

Looks like those cheapo Chinese cruddy things popular in smaller sizes sold here from supermarkets by oddball makes like UMC! All Utter Trash!...

Prolly a few LED's gone short and one (or two) gone open...

Yep, HITACHI in name only. Will not be surprised if it has bad LEDs.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

A is 0.74DCV
B is 0.00DCV
C is 0.78DCV
D is 0.00DCV

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

A is 0.74DCV
B is 0.00DCV
C is 0.78DCV
D is 0.00DCV

Well, that means the LED power supply is not working at all, more in-depth troubleshooting will be required which means you have to trace out the circuits on the board.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

BTW, are you getting about 380~400VDC measured between the two legs of the main filter cap when the TV is on?

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

As soon as I took the back panel off the first thing that came to my mind was that this chassis looks familiar so it's definitely rebranded. HKC(Shen Zhen) panel and HKC power supply and AUO Main with a no name huge tcon. Made in China. The main looks similar to Hisense Mains. So, in this case possible shorts on 2 out of 4 strips? By the way, thanks BudM for taking the time to show me how to test the led's on this model. It was manufactured 11/15 and we are starting to see a lot of LG LN Series coming in with bad led's, just a shame to see such a quick failure rate.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

You can disconnect all the LED connectors to see if you get the DCV on 'A' and 'C'. I had a couple of HISEN TVs that the LED wire assemblies were shorted (nicks in the wires) to the the chassis inside the panel.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Wow, only 161DCV, maybe there is hope. Bad power supply then?