HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

[leo-saphira]

Hello all

Its been a while since I done some on board component repairs - (other than last weeks replacement of caps on sayno set) its been nearly 16 years since I was last in the trade, so time to have a tinker with a few to get them going again.

Picked up this HITACHI 32HXC01U set (Vestal board) for sum of £15 today - there is no LED back light on at all but you can make out the menus on the screen.

Inside it has a Vestal 17IPS19-5 V.1 061112 Board in it. Testing on the PL501 socket it showing no voltage

Can some nice folk reteach me again - to get this one going

Many Thanks

Mick

[leo-saphira]

Re: HITACHI 32HXC01U - No backlight

Image of the board:

[leo-saphira]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

and the rear photo

[budm]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

It looks like the same board as used in this TV:
https://www.badcaps.net/forum/showthread.php?t=34222

Can we see the whole back side of the TV so we can see how all the boards and the LED strings are connected together?
We will have to check the DCV on the bottom left section (3 diodes, 3 large caps and 2 small caps) which is the LED driver circuit. You can check the DVC on those caps, measure them between the two legs of the caps.

[tom66]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

A known fault on these is shorted diode and FET in boost stage causing 24V to drop out.
The set I had had a continuous flashing LED code, some might just not turn the backlight on (it depends on the design, if the main board uses 24V or not)

[satinser]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

I have exactly the same problem with no backlight. In your last post Tom you pointed out it was a common fault with a diode and FET failing in boost stage causing 24volt to drop out. Any chance you could elaborate on the circuit ref numbers of the components you were referring too.

[satinser]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Still got problems with this TV. No backlight. Would really appreciate if you could advise which diode and FET you were referring too. Apologies for raising this matter up again.

[tom66]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Still got problems with this TV. No backlight. Would really appreciate if you could advise which diode and FET you were referring too. Apologies for raising this matter up again.

It's on the power board near the LED conn - can't recall refdes # but it's SMD, on the bottom side, the diode is on the top. Note the schematic is wrong about the FET part (that got me first time) it specifies a 30V part when the actual part is 60V rated. I used a spare 80V through hole FET from a Sharp inverter, it worked this PSU has options for a through hole FET too.

[leo-saphira]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Hi Tom - got this out again - have been busy - had swapped over the psu and the main board from another set like this and still produces the same fault where the back light doesn't come on - so its the leds inside the panel itself.

[brianbelfast]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Did you ever sort this one out ? Did it turn out to be the leds as you said ? I've one just arrived with the same problem. Supply to the leds fires up for a split second to around 80v when you bring it out of standby but slowly falls gradually again. Picture can be seen on the screen. Just no backlight.

[brianbelfast]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Ok turns out that the symptom I am getting is the LCD driver IC sensing that the LED array in the screen is open circuit and shutting down. Now to dismantle the lcd panel and see why.

[ColonelPorter]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Hi folks,
I have a backlight out on this same set.
A look at the array of leds shows no fancy circuitry, so I'm assuming I can apply 24v across the backlight connector to check for correct illumination.
If it's the Vestel PSU board is there a recommended sequence for component replacement.
The set is like new - just out of warranty!
Any help much appreciated.

Colonel P.

[ReeceyBurger123]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

You wont be able to fire the leds on with 24v they need about 48v for one of them strips. You can however check for S/C across the leds. Can you see any that look burnt through the optic ?
Also does the Psu have the 24v working if so probably is leds ?

[brianbelfast]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Metered them individually. One shorted and one Open circuit. Lit the rest of them individually with 5v supply and resistor. Now I'm trying to find a source for suitable replacements.

Any idea of the specs ? They look like 7000k or higher in colour by the look of them

[ColonelPorter]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Folks,

Plugged an array of 12, 2V LEDs into backlight cable. Does anyone have a schematic to check the voltage for me?

LEDs flash on and then voltage decays from about 40-0V (DMM)

Not sure I'm any wiser yet. I'm going to try and power up backlight with a PWM supply and see if they light.

If all else fails I'll just try some strip leds and an external supply. Trawled the web for a supplier - there's a USA company doing CCFLs and LEDs but not for this model.

There seems to be a number of variants of this board too.

Cheers

[ColonelPorter]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

DMM says array is o/c....

post somewhere said driver IC monitors array and shuts down if s/c o/c...

That would suggest array voltage can only be checked with working array connected???

[Alexhargreaves]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Hi All,

I hope this thread is still active as have the same problem.

My spare TV is a Hitachi 32HXC01U and the backlight recently failed. Everything else seems fine - it happily goes into standby, the audio is still working, and a picture is visible when I manually illuminat the screen, so I assume there is just a problem backlight.

I popped it open yesterday to see what was going on and the board is the same as above - Vestal 17IPS19-5 V.1 061112 - looks the same as the above picture as well.

I assumed it was a problem, with the LED driver however after reading the thread, I guess it could be something more serious. Is there an easy way I can check what the exact problem is?

Sorry if that is a bit of a stupid question, although I am reasonably confident with electronics, I have never tried to repair a TV before, so don't really know where to start...

Cheers,

Alex

[Anor1412]

Re: HITACHI 32HXC01U - No backlight - Vestal 17IPS19-5 V.1 061112

Hi having same issue as person above. Still fairly new to self repairs outside of work but promised my Mrs I'd have a try and repairing. On a novice level could anyone explain to me how I would fix this problem. You can see the menu when you shine a torch on the screen. Any help would be great guys thanks