BUSH LED40127FHDCNTD, flashing LED'S

[finntricky]

just got hold of this and was told working but the screen is flashing,
great, i thought,dead led causing the problem, well it turns out after removing the screen it is bottom lit with LED'S, i've put a video up on youtube https://www.youtube.com/watch?v=P_y-TTOpEU4
so you can see what happens,
checked the normal diodes and mosfet, but all are fine, anyone got any ideas,
voltage from the power board to LED's seem stable ?

[flocko]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Check the 4 string driver IC MP3394S and 14N25 fet on rear of the power board. most common parts that fail on the LED side of this board

[budm]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Any pictures of the bottom side of the power supply-LED driver board?
I am not sure if this SCH is the exact match of your board or not

[finntricky]

Re: BUSH LED40127FHDCNTD, flashing LED'S

bottom of board as asked for.
fet test ok, no shorts, but the big IC, if thats the one your talking about, then i have no idea how to test.

[dick_barton]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Data sheet may be able to help you diagnose the chip.

[budm]

Re: BUSH LED40127FHDCNTD, flashing LED'S

So the Boosted Voltage at the LED connector PL500 pin 1 and 5 steady?
And the Dimming control signal at connector PL201 pin 2 is also steady? Same for BL_ON/OFF pin 1? Same for +24V?

[finntricky]

Re: BUSH LED40127FHDCNTD, flashing LED'S

right, just been messing with the picture settings in the menu, i have stopped it from flashing, i have turned ECO OFF and GAME mode on, this is the only setting that the LED's are not flashing, maybe this will give a better idea as to where the problem is, any other picture mode on the tv is flashing and darker with ECO OFF

[budm]

Re: BUSH LED40127FHDCNTD, flashing LED'S

So if you reduce the backlights level to as low as possible, the LEDs will stop flashing in any mode?

[finntricky]

Re: BUSH LED40127FHDCNTD, flashing LED'S

cant find a backlight level ajustment ?

[ReeceyBurger123]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Intermittent Led within the strip not fucking easy to find Does the Bl go completely out after a min or two ?

[budm]

Re: BUSH LED40127FHDCNTD, flashing LED'S



It says OPTION so not sure what it really means for this model, is it greyed out?

[vinceroger69]

Re: BUSH LED40127FHDCNTD, flashing LED'S

ignore my bush uses a diffrent main board

[ReeceyBurger123]

Re: BUSH LED40127FHDCNTD, flashing LED'S

This is a Vestel set so there is. Set the picture to "dynamic" then yoh can set the Bl to "low" doing this will turn off any other adjustments for the Bl on these sets.

[finntricky]

Re: BUSH LED40127FHDCNTD, flashing LED'S

its ok, got it, because it was on game, the backlight was on auto, and could not be changed,
so this is what i now have, with backlights on full, i have 3 modes that are fine, GAME, SPORT, DYNAMIC,
other modes still flash,
setting the backlight to any lower setting it all goes back to flashing, so where is the problem,? Mainboard ? or the IC on the power board ?

[finntricky]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Intermittent Led within the strip not fucking easy to find Does the Bl go completely out after a min or two ?

no, just keeps flashing,

[ReeceyBurger123]

Re: BUSH LED40127FHDCNTD, flashing LED'S

I would say the Ic that sends the Pwm signals to the Led boost mosfet is failing. Its on the power board and im also sure its a common failure on these boards too. Wait and see what others think.

[budm]

Re: BUSH LED40127FHDCNTD, flashing LED'S

I already asked about the dimming signal on post #6 but no response.

[jczarniak]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Hi,
I've got same television, where sound works fine, backlight is on but no picture.
Any ideas what's wrong?
Thank you.
Regards.

[vinceroger69]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Hi,
I've got same television, where sound works fine, backlight is on but no picture.
Any ideas what's wrong?
Thank you.
Regards.

what tests have you done have you checked the voltage to each side of the tcon fuse etc.

[ReeceyBurger123]

Re: BUSH LED40127FHDCNTD, flashing LED'S

Fin an update ?