HiSense 55H6570F

[papillon]

Looking for help in figuring out how to narrow down the source of the problem for a HiSense 55H6570F with an integrated multi-function board*

When plugged in, the power LED blinks a fraction of a second. The TV cannot be powered on, no activity on the LCD. The LCD was removed and the LEDs were tested individually: all are working fine.

The output of the transformer is 95.5v. The positive lead out of the LED driver (LEDP) outputs ~191.2v while the negative terminal (LEDN) starts at the same value and gradually drops to 97.2v after a few moments

The connector (top right on image) has a pin at 5v and another one at 3.3v

No visible signes of failure (burnt components, blown caps, etc) on the board

What else can I test to determine what's wrong with this board?
thanks for your insight!

[howardc64]

Re: HiSense 55H6570F

I have about the same problem also on a HiSense TV. Your board is more integrated than mine (PSU+main+T-Con all in one)

https://www.badcaps.net/forum/showpo...14&postcount=1

I think the blink once standby light after plugging in AC (same as mine) basically says main board CPU isn't booting very far to turn it on.

Slowly debugging mine, a couple of power rails that CPU is suppose to turn on isn't on so something is causing the CPU processing to not function properly

If you know how to figure out where to probe voltages (heat sink probably have to come off, easy), can see if USB 5v is on (my USB port that does firmware updates has no power), 1.5v for DRAM, 1v for CPU etc.. T-Con section is probably dead like mine.

[papillon]

Re: HiSense 55H6570F

If you know how to figure out where to probe voltages (heat sink probably have to come off, easy), can see if USB 5v is on (my USB port that does firmware updates has no power), 1.5v for DRAM, 1v for CPU etc.. T-Con section is probably dead like mine.

Thanks for your input.
I noticed in your post that you tried re heating the board/CPU. Did that help at all?

I noticed a lot of heat coming from the array of resistors below the LED connector, so I'll start to probe around there. What kind of voltages are you getting (if any) from the LED driver?

[Diah]

Re: HiSense 55H6570F

yours TV MB are the worse one. its not only all in one.. but its design MB all in one... one CPU drive TV and its GPU. its similar to 15$ TV box only the out put they deliver it to panel t-con.
try to capture start log via UART first to know which part are not in tact RAM / EMMC or the master CPU

[howardc64]

Re: HiSense 55H6570F

Thanks for your input.
I noticed in your post that you tried re heating the board/CPU. Did that help at all?

I noticed a lot of heat coming from the array of resistors below the LED connector, so I'll start to probe around there. What kind of voltages are you getting (if any) from the LED driver?

posted LED voltages in post #5/#7. They look strange but don't really know the HiSense design. Post #3 also details jumping the signal pin that turns backlight on and got my backlight to flash on/off quickly.

heated the SOC (with heatsink off) slightly, no difference.

Just updated post #24 which details tracing through various power rails on the main board. Quite a bit of effort if you want follow that path.

[papillon]

Re: HiSense 55H6570F

Just updated post #24 which details tracing through various power rails on the main board. Quite a bit of effort if you want follow that path.

Was just reading your latest comment and considering that hisense is not making the firmware readily available, I am concluding that getting a replacement board is likely the only practical option at this time. thanks for sharing your findings

[howardc64]

Re: HiSense 55H6570F

Was just reading your latest comment and considering that hisense is not making the firmware readily available, I am concluding that getting a replacement board is likely the only practical option at this time. thanks for sharing your findings

yeah, don't know if you want to make a USB<->3.5mm jack serial dongle like I did in post #28. Would provide a lot more insight on main board's boot activities. Dongle is $3 on amazon ( link ) and just just find and cut a 3.5mm audio jack + soldering 3 lines. I showed pic of my old one ( just found it today) but the new amazon one came today and easier to use.

Looks like board for your TV is crazy expensive and out of stock like mine. Probably lots of these HiSense TV boards dying severely limiting the supply.