Hitachi LE65K6R9 has menu image but no backlights

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

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

Is that the reading when PS-ON is present?

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

Need to get the P/N of the 8-pin SMD next to the PFC INDUCTOR L8 to find out if it is getting the VCC to run or not.
https://www.badcaps.net/forum/attach...9&d=1473343187

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Still no voltages on those two pins with the red and white led connectors disconected. We are a cell phone/gadget repair shop and we love to learn new things and learn from this forum about Tv repair in our spare time. So we are trying to learn how to diagnose Tv's and do more component level repair we have learned here.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Yes, I get 165DCV with the Tv turned on

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

Need to get that P/N of the PFC IC per post 22.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

Need to check PFC diodes, and also good clear pictures of the area in red box top side and bottom side of the board.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

It looks like it's U4 but there is no part numbers on the top. Do I leave ground on chassis and check the legs for voltages with the tv on?

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

The two diodes D34 and D6 each read 0.410 and the 8 pin at U4 just has a lot of liquor with no numbers

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Here is a close up under the microscope for that 8 pin at U4. I scraped away some of the coating but still didn't see any numbers

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

Try Alcohol or Acetone on the Q-TIP to remove the stuff off the top of the IC.
The VCC will be read between the GND pin (or negative leg of the main filter cap in the primary side and the VCC pin, do not use chassis GND because you are working on the primary side, the Negative leg of the main filter cap is the GND ref. point for the meter.
We cannot do much unless we have the P/N of the IC, otherwise it will be a lot of board tracing.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

I'm looking at it under the microscope and can't see any numbers on that 8 pin on U4. I found a OEM board for $88.00 so I can order one and I'll probably look at that U4 to see if it has numbers so I can find out the specs on it before I install the new one. If I can get one from mouser or digikey I'd like to change that out to see if that is what kept the backlights from coming on. Thanks for your patience and sharing the knowledge. I almost forgot the importance of grounding on the filter cap vs chassis on the hot side so thanks for reminding me. When I got proper voltages on the connector I didn't think to check the voltages on the main filter cap especially when I could see a menu image. Thank you sir.

[budm]

Re: Hitachi LE65K6R9 has menu image but no backlights

BTW, ORION is the OEM of HITACHI, and a lot of other brands.
https://en.wikipedia.org/wiki/Orion_Electric

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Thanks for the info BudM. I didn't relize Orion made Tv's for so many brands which explains why I've probably seen this chassis before. I live near Wal Mart headquarters and they are spewing this crap out to their customers with no regard for quality. We are starting to see pre-mature backlight failures so with your help we are learning proper diagnostic procedures and learning how to trace the boards more in order to do more component level repairs vs board swapping for maximum profits. I'll update as soon as the new board comes in and hopefully I can find some numbers on the 8 pin ic to see what the specs are before I install it.

[brucetv]

Re: Hitachi LE65K6R9 has menu image but no backlights

Update. The new power supply came in and I looked at the U4 but once again it had a ton of protective coating and my isopropyl alcohol didn't budge it but did magnify it and it looked like a WM and 4 numbers. The Tv fired up nicely and I was glad to see that it was actually a bad component on the LED Driver/Power Supply vs bad led's. I wasn't in the mood to remove a 65" panel. I will examine the board and hope to find the shorted circuit and update when I get caught back up in the shop. Thanks Budm for all your help.