HiSense 65H6510G no boot

[howardc64]

TV standby light flash once after plug-in AC power. Then silent. No backlight, no LCD image on flash light test, no SPDIF light.



All PSU voltages to main looks good (12v, 20v (label says 18v but is 20), standby voltage) Probing main board shows what appears to be a DCDC converter (MSH6103A can't find datasheet) providing 5v, 3.3v and 1v. 5v present to the standby light power switch board.



These HiSense TVs appears to have lots of firmware corruptions that takes out the main board either through smartTV use or firmware update. Used main board prices are quite high probably due to so many main boards failing from poor firmware. Since I only get 1 blink on the standby light, probably even basic boot firmware has corrupted (>1 blinks will indicate some failure status)

Main SOC is a MStar msd6886NQHT (MStar bought out by MediaTek in 2019 according to Phillips lawsuit docs in US ITC court filing link p48 )

Found this 2018 service guide for MSD5886 showing UART access to the TV to flash various boot/firmware bits

https://www.manualslib.com/manual/16...roduct-MSD6886

p28 shows a serial port connection to the earphone port. My TV has both an earphone and service port (also earphone plug shape) right next to it. Service port plug solder points appears to show its just a TRS 3.5mm plug port



https://www.headphonesty.com/2019/04...uctor_plug_TRS

Looks pretty easy to make the DB9 to TRS 3.5mm cable (pin 2/3/5) and can buy these off the shelf programming cables

https://www.youtube.com/watch?v=4riU...elliteTrackers

Then its onto finding software and this TV's boot/firmware bits.

Flashing in boot/firmware via serial ports is pretty standard Android flashing process. Recently did this on my Chinese Android HeadUnit for the car. Just need the cable, Flashing firmware (usually from main SOC maker) and trigger SOC to reset.

Anyone has experience with this? Also probably unlikely to get boot/firmware bits from HiSense so probably need a flash in a raw dump?

I'll try heating the main SOC slightly to see if any help but given the % of firmware failures on this TV, corruption boot/firmware seems the most likely candidate.

[Diah]

Re: HiSense 65H6510G no boot

you are diving at wrong ocean...
lets go back to original issue while all in original connecting.. give read of the socket which goes to main-boards and LED socket high and low at first start

[howardc64]

Re: HiSense 65H6510G no boot

you are diving at wrong ocean...
lets go back to original issue while all in original connecting.. give read of the socket which goes to main-boards and LED socket high and low at first start

Don't know if BSW is turning backlight on but < 1v after plugging in AC and no change pressing power switch on TV. Anyway, none of the main connector voltages change pressing power button on the TV (not remote)

Shopjimmy shows 10 strips of 6 LEDs so LED tester shows 10v below 90v assuming 3v LEDs.

https://www.shopjimmy.com/hisense-lb...ght-strips-10/

googling HiSense standby light blinking codes shows 2 blinks = bad LED. Anyway, I have no standby light at all (briefly flash after plugging in AC) So most signs seems to point to dead main

[Diah]

Re: HiSense 65H6510G no boot

you are still diving at wrong ocean
if you work on what SJ write and advertised then no need to post over here.... they sell parts not to diagnose issue..
yours photo remark voltage i cant understand from it any point.. as its out of my poor English knowledge.. sorry

[howardc64]

Re: HiSense 65H6510G no boot

yours photo remark voltage[/URL] i cant understand from it any point.. as its out of my poor English knowledge.. sorry

4 pins on PSU LED connector. Presumably 2 serial circuits.

blue
white
red
black

volt meter ground probe on chassis

blue = 195v
white = 124v
red = 195v
black = 124v

meter + on blue, meter - on white = 0v
meter + on red, meter - on black = 0v

These voltage reading starts when plugging in AC cord and never change with pressing TV power button.

LED tester + on blue and - on white light up LED and reads 79.2v
LED tester + on red and - on black light up LED and reads 79.2v

I only use shopjimmy reference to see # of LEDs. Of course it may not be exact to whats in the TV. To see whats in the TV require a lot more disassembly.

[Diah]

Re: HiSense 65H6510G no boot

disconnect the MB from socket XP810 and tested the voltage you have on it and on the LED BL socket with references to TV chassis

[howardc64]

Re: HiSense 65H6510G no boot

disconnect the MB from socket XP810 and tested the voltage you have on it and on the LED BL socket with references to TV chassis

XP810 disconnected from main

BSW BRI 0v
18/12v = 20v
all 12v = 9.4v

BL Connector (volt meter - on chassis)

Connected to backlight

blue and red = 190v when plug in AC and continuously dropping
white and black = 120v when plug in AC and continuously dropping

Disconnected from backlight

blue and red = 190v when plug in AC and continuously dropping
white and black = < 10v and continuously dropping

[Diah]

Re: HiSense 65H6510G no boot

if you are sure MB disconnected and this is the value u have,,, then you have one Optokoppler between primary and secondary PWB defect

[nomoresonys]

Re: HiSense 65H6510G no boot

Maybe try the powerboard as stand alone and see if you get steady voltages and backlights on.

[howardc64]

Re: HiSense 65H6510G no boot

if you are sure MB disconnected and this is the value u have,,, then you have one Optokoppler between primary and secondary PWB defect

I only see 1 optocoupler on bottom of PSU (right of center). The diode side measures good (1325 in forward bias, 0 in reverse ) Don't know how to check emitter collector side in circuit.

Maybe try the powerboard as stand alone and see if you get steady voltages and backlights on.

PSU doesn't light up backlight with main disconnected. Anyway, there is clear evidence main is dead. Here is latest summary

I believe the boot sequence is as follows

- PSU generate 12v to main and 20v (not sure what this is for, maybe tcon or audio amp? I have seen LG tcon's PMIC generate 20v+ VGH from 12v)
- If main boots properly, it will turn on standby light and power on IR. If TV is requested to power on, main will tell PSU to turn on backlight along with supplying analog or PWM dimming signals. PSU on this board shows ANA signal at a minimum (I've seen ANA and PWM dimming on a 55 Samsung but not sure HiSense have both)
- BSW (Backlight Switch?) between PSU and main is likely the signal main uses to tell PSU to turn on backlight. Goes to about 0.8v when AC is plugged in. I jumped this line with 3.3v standby (generated by main's DCDC power tree) and saw backlight flash on briefly. I'm guessing probably need to supply proper ANA signal (maybe jump 3.3v also) to keep it staying on.

- Main's DCDC power rails use PSU's 12v to converts to all the necessary voltages to drive its components starting with the computing system (CPU=1v, DDR3=1.5v, eMMC=3.3v and 1.8v) just to be able to boot the computer. Other voltages like 5v exist for USB, IR, wifi, etc
-All of the main's computing system voltages are present checking around SOC/DDR3/eMMC. One of the 2 USB port has no 5V. Circuit trace (service manual has the circuit diagram) shows its enabled by the CPU so CPU didn't get that far.
- FLIR image of main shows one region of SOC and one side of eMMC warms up on plugging in AC. This likely shows everything is configured to start reading boot/system code from eMMC. The correct boot sequence on AC plug in would be to enable IR and turn on standby light at a minimum. But lacking standby light, 2nd USB port power, no SPDIF light etc... means SOC didn't get very far.

So main is dead and I suspect it is likely firmware. Main boards for this TV (3 years old) is out of stock everywhere @ $100. Many complaints of slow smarttv software and bricking from updating the TV. Anyhow, Hisense doesn't even provide USB recovery firmware without request. Not sure can get PC flashed tools and firmware.

So to summarize, main has the 12v source from PSU and DCDC generates all voltages for the SOC, DDR3, eMMC but no evidence its booting very far. Don't think I want to invest $100+ on a replacement main so will see if can gather enough SOC tools to see if can at least get a terminal prompt over the service port (3.5mm jack for serial UART signal)

[dan8139]

Re: HiSense 65H6510G no boot

I hate situations like this. It's the way of the world sadly.
Can you scope something on the ARM chip to at least see if it's alive (clock etc)?
Wish you luck.
Did you say earlier the 12v rail was at 9.4v?
Why is the 12v at 9.4v?

[howardc64]

Re: HiSense 65H6510G no boot

I hate situations like this. It's the way of the world sadly.
Can you scope something on the ARM chip to at least see if it's alive (clock etc)?
Wish you luck.

Unfortunately no scope or logic analyzer. That would be helpful of course. But I suppose seeing heat signature in one spot in the SOC and one side of eMMC indicate there is clock (or a short of course but my probe found none)

And been fixing lots of easy fixes (change LED backlight, blown PSU caps, shorted panel edge driver caps and flex etc) Finally hit a couple of hard ones like this haha.

Did you say earlier the 12v rail was at 9.4v?
Why is the 12v at 9.4v?

Yes, PSU has a couple of mysteries and I know nothing about power electronics

Just doubled checked and it will read 12.5v (solid and steady) when main is connected. When main is not connected, Connecting AC and multimeter will read 9.5-12+v (depending on how long leave AC disconnected, seems to get higher voltage if disconnected longer) and quickly drop to settle in at 9.4v. Traced it back to the 2 rectifier that generates 20v and 12v. Will read 12v at rectifier output when main disconnected (can no load cause this?) Here is pic and data sheet for the 6 cold side rectifiers



https://datasheetspdf.com/pdf/108335.../2CZ20100A9S/1
https://datasheetspdf.com/pdf/100455...tor/10F40HF3/1

Also many TV PSU will light up LEDs when main is disconnected. I guess must be default behavior without main. Don't have a reference on this HiSense. Great if someone can chime in if HiSense (ideally this model) does the same.

[howardc64]

Re: HiSense 65H6510G no boot

UPDATE

The PSU does make a faint noise differently with main connected and disconnected. Furthermore, one periodic noise correlates with voltage drops.

Main Connected

- Every ~30s will hear a faint 1/2s squeal sound near the big transformer (haven't isolate it exactly where from) when this sound occurs, all DC voltages will drop momentarily. 195v will drop about 10v on digital volt meter. Even main side's 1v CPU supply voltage will drop a tiny amount (few 100th of a volt on the meter)

Main disconnected

- No periodic squeal but a faint clicking sound that speeds up after plugging in AC which seem to gradually become steady clicking frequency.

So I guess PSU could still be suspect as without a scope, can't see how clean the DC voltages are going to main.

[Diah]

Re: HiSense 65H6510G no boot

i need to correct my post #8
i just learned yours TV Android. so the PWB will be in high always for warm start 12 / 20 V.
so the boot loop caused by MB either emmc or CPU / RAM BGA or could be Firmware too since its android... try to contact Hisense and ask them for Firmware if you couldnt find in net

[nomoresonys]

Re: HiSense 65H6510G no boot

Check all solder joints with microscope, and give m the wiggle test which works good to find one that looks good but isn't.

[howardc64]

Re: HiSense 65H6510G no boot

i need to correct my post #8
i just learned yours TV Android. so the PWB will be in high always for warm start 12 / 20 V.

Yes its Android TV. Can you explain what "PWB will be in high mean"? Does it mean backlight voltage will not be final?

FYI, I also learned 20V = VCC_A for the audio amp from the service manual schematic.

so the boot loop caused by MB either emmc or CPU / RAM BGA or could be Firmware too since its android... try to contact Hisense and ask them for Firmware if you couldnt find in net

I guess you are thinking the periodic ~30s PWB squeal / brief voltage drop is main board boot loop. Checked all signal from main->PWB and all are steady when this occurs

STB = 3.43v
BSW = 0.084v (I think this is backlight switch)
BRI = 0.084v (probably PWM dimming according to service manual schematic)
ANA = 0v (PWM2 in service manual schematic)

From PWB

VCC_A = 20v will drop momentarily when this occurs
12V = 12.5 steady when this occurs

Possible ~30s PWB squeal / voltage drop is caused by PWB? This does not occur with main disconnected but all the voltages aren't stable or don't look correct when main is disconnected anyways.

could be Firmware too since its android... try to contact Hisense and ask them for Firmware if you couldnt find in net

Contacted HiSense. My understanding from service manual is to first get mboot working to enable USB flash upgrade.

MSTV_Tool.exe and ID password to complete "deciphering" which seems to be "unlock ability to flashing eMMC"
ISP_Tool to flash mboot to eMMC
Correct TV bin file for USB upgrading

Seems like many firmware corruptions just require USB upgrade so mboot remains intact and main gets far enough to light up the screen with logo. If this one is firmware failure, then it would have also corrupted mboot.

Check all solder joints with microscope, and give m the wiggle test which works good to find one that looks good but isn't.

Will do, hard to untangle which is bad (PWB or main) so will proceed both for now.

[Diah]

Re: HiSense 65H6510G no boot

since its Android. there are no Mboot... will be bootloader... and if the bootloader not in tact then no more reboot or try to reboot.

suggested in your case remove any load from MB... BT or WIFI.... speaker ... BGA at the parts i mentioned before cause this too.... at the end all repair level just replace boards. if there are no Oscilloscope in hand.

[lotas]

Re: HiSense 65H6510G no boot

Try to find the TX and RX points on the board, connect the UART to USB adapter to them, run the terminal program and look at the terminal boot log, and you will see where the problem is. (The main thing is that UART is not disabled in the firmware itself).

[howardc64]

Re: HiSense 65H6510G no boot

since its Android. there are no Mboot... will be bootloader... and if the bootloader not in tact then no more reboot or try to reboot.

Thanks, will look for bootloader.

suggested in your case remove any load from MB... BT or WIFI.... speaker ... BGA at the parts i mentioned before cause this too.... at the end all repair level just replace boards. if there are no Oscilloscope in hand.

Tried removing all connectors (panel, wifi, speaker, with and without IR+power button) and unfortunately no sign of booting (no SPDIF, CPU enabled USB port power)

And yes, without scope, hard to make much progress other than board swap. Given the availability and cost of the boards > $100, most owners encountering are just trashing the TVs

Try to find the TX and RX points on the board, connect the UART to USB adapter to them, run the terminal program and look at the terminal boot log, and you will see where the problem is. (The main thing is that UART is not disabled in the firmware itself).

Yes, TV has 3.5mm audio jack for service port that is UART. Searching for my USB UART dongle or order one or find old DB9 computer and build a cable. Then I'll have more insight on CPU activity/any logs.

Since there are so many firmware failures on these HiSense Android TVs, am motivated to see if can succeed firmware reinstall to publish procedure and help save more of these hisense TVs

[howardc64]

Re: HiSense 65H6510G no boot

Anyone knows necessary spec for the HW UART connection to this TV?

Service Manual for 2018 HiSense (link in post #1, this TV is 2020 but use same main SOC) shows a HiSense serial board RSAG7.820.2335T with USB to PC and DB9->3.5mm jack to service port.

Same 2018 service manual shows UART circuit diagram which connects directly to main SOC (probably 3.3v GPIO?). I'm guessing the proper signaling probably requires 3.3v RX/TX. I measured the service port directly and see 3.3v



Finally, has anyone used a cheap USB<->Serial TTL dongle based on FT232RL or CH340G to connect to UART on these HiSense TV's service ports? Both of these have changeable RX/TX voltage from 5 to 3.3v.

Just want to make sure I gather the correct USB to UART HW.

Thanks