Hisense 32K20DW missing LED voltages and 6 blinks

[ReeceyBurger123]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

150v is for the 40" size, Tv, this is the 32" so it will be 90v at start then 70 running.

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

No, no flash from the backlights. I can, barely, see the "Highsense" emblem with a flashlight.

Has anyone tried wiring up a test backlight LED string? From other posts it looks like if even one LED fails open, the TV senses no current and shuts down.

There is ~85V on the high pin LP, and less than 24 VDC on the LN pin. When I unplug the LED string LN goes to 0.

[ReeceyBurger123]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

So wait do you get brief Led voltage of about 90v ?

[budm]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

'When I unplug the LED string LN goes to 0'

How about LP without LED connected?
If the meter is fast enough:
85V- 24V = 61V Total Vf.
61V/3V = about 20 LEDs, does not sound right for 32 inch panel, may be some of the LEDs are shorted which may have cause the original MOSFET to be bad in the first place.
What is the panel model number?

[CapLeaker]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

You can capture this what budm asked easily with the min/max function of you DMM (if yours has that).

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

Are LED strips from a 40" Hisense the same length, so compatible to use in this 32"? I have a chance to buy a non-working 40".

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

I finally got up the nerve to open the panel and test the backlight strips. Two test fine on all LEDs with diode check. The third has two dead LEDs. I see a few incompatible strips on ebay. Where can I buy the little square diodes? Do you pros have a part number?
The identical strips have several numbers. I've gotten hits for keywords E227809C but not for HE32VLEAK14010503847 , 1130209 or 89ma062L-B1.

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

Persistence paid off!
I replaced the open LEDs with 3 types before I got one in that does not die instantly. And only 1mm thick like the originals. The panel has been all lit up for 15 minutes so far; I'm going for an hour before I put it back together.
In case anyone reading wants to try this repair, the led ic's that work are Digikey 1516-1050-1-ND AKA Brightek QBHP686-IWK-CW. An entire 3mm by 2.5mm by 1mm thick.

[vinceroger69]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

Thanks for the update and glad the tvs repaired also with the new led fitted and the tv back together can you notice any diffrence in colour/brightness of the new led when watching the tv?

[budm]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

http://www.digikey.com/product-searc...1516-1050-1-ND

https://cdn.badcaps-static.com/pdfs/...28bd5c6399.pdf
Only 75mA max current, I hope you will keep an eye on them.

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

What is the least maximum current I should look for? I have 61 VDC lighting 18 LEDs.

[budm]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

300mA or higher.

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

K, thanks!
I ordered these:
MXA7-PW65-H001 Lumilite from Digikey. The 'working' replacements worked about an hour before one went out.

To Vince_Rodgers, The two replacements looked slightly yellower without any diffuser, essentially the same. I won't reassemble the panel until the LED strip works for an hour or more.

[ReeceyBurger123]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

Awesomeness

[budm]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

BTW, you should also turn down the backlights level down to as low as possible.

[steves7839]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

Here's a pic of the exposed LED strips powering 300mA smd LEDs. If these stay on a full hour I will put the panel back together. The color is a bit yellower than the originals, similar to the earlier replacements that lasted about an hour. But the LED is described by its manufacturer as "Luxeon Cool White 6500K 2SMD". Perhaps a better match would be obtained with daylight color, 7000K or so. I hope the filter panel will absorb the color difference.
No more fault codes, at least!

[rylos]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

The LEDS I've used in several LG & Vizio sets are # LATWT470RELZK, 400 ma., cool white. Several places sell them an Ali Express. I bought a lot of 500 for about $23. They were a drop-in replacement. Procedure I use is remove the light diffuser domes, being careful to number each one for location & orientation (if you don't get them back on just right, the backlighting will be blotchy). Remove original LED (I replace the entire set, in case others are getting close to failure), scrape coating off board next to the end that's more accesible (between two posts) heat both ends alternately with soldering iron while prying at LED with small screwdriver, LED will probably break apart into 2 pieces. Remove solder from board pads with soder-wick. Put a small amount of solder on the smaller pad. smaer a small amount of rosin flux on LED terminals. Melt the solder blob on the smaller pad while placing LED into position. Check for short, in case LED not positioned quite right. The diode test function on a DVM will probably make the LED glow slightly. If no short, then flow a bit of solder at the other terminal, making use of the scraped-off area of pad to halp conduct heat, the solder will wick into place under the larger LED terminal. Check again for short / light up LED. After all LEDs replaced, glue diffuser domes back on, taking care to position them as original. I use JB weld in a syringe, use new batch of glue every 15 minutes or so to maintain stickyness.

[smalltownguy]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

The LEDS I've used in several LG & Vizio sets are # LATWT470RELZK, 400 ma., cool white. Several places sell them an Ali Express. I bought a lot of 500 for about $23. They were a drop-in replacement. Procedure I use is remove the light diffuser domes, being careful to number each one for location & orientation (if you don't get them back on just right, the backlighting will be blotchy). Remove original LED (I replace the entire set, in case others are getting close to failure), scrape coating off board next to the end that's more accesible (between two posts) heat both ends alternately with soldering iron while prying at LED with small screwdriver, LED will probably break apart into 2 pieces. Remove solder from board pads with soder-wick. Put a small amount of solder on the smaller pad. smaer a small amount of rosin flux on LED terminals. Melt the solder blob on the smaller pad while placing LED into position. Check for short, in case LED not positioned quite right. The diode test function on a DVM will probably make the LED glow slightly. If no short, then flow a bit of solder at the other terminal, making use of the scraped-off area of pad to halp conduct heat, the solder will wick into place under the larger LED terminal. Check again for short / light up LED. After all LEDs replaced, glue diffuser domes back on, taking care to position them as original. I use JB weld in a syringe, use new batch of glue every 15 minutes or so to maintain stickyness.

Rylos, would you be willing to send me a handful of those LEDs? I'm in the middle of repairing a 32" Insignia TV that has a shorted LED and I'm not finding any local supplies of LED's easily. Unless you can point me to something maybe on DigiKey or Mouser?

[budm]

Re: Hisense 32K20DW missing LED voltages and 6 blinks

You have to make sure if the large solder pad of the original LED is Cathode or Anode which you have to match that with the replacement LED. otherwise the heat will not be dissipated properly to the strip.

https://www.badcaps.net/forum/showpo...&postcount=282