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Electronics => Repair => Topic started by: Gominalo on November 07, 2024, 04:21:20 pm

Title: Industrial LCD display
Post by: Gominalo on November 07, 2024, 04:21:20 pm
Hi all,

I am facing to a LCD display that died suddently during weekend. I've been checking voltages and they seem to be okay, next step i think will be T-CON pcb.
Can anyone guide me through troubleshooting? (Signals to be checked, power-up sequence...)
The display is used for a semiconductor wafer prober, see photos.

Thank you.
Title: Re: Industrial LCD display
Post by: BennoG on November 07, 2024, 05:48:21 pm
usually the backlight breaks down on this type of units.
If you shine a bright light on the front can you see the image a little ?
Benno
Title: Re: Industrial LCD display
Post by: coromonadalix on November 07, 2024, 05:53:50 pm
the backlight board as 4 outputs on it, or 2 in parallel ? 

check if you see markings on it, who would help you   for voltages and control pins


t-con is not for backlight ...


do i see tdk  something  on the ccfl  board   can you show us photos or write the numbers
Title: Re: Industrial LCD display
Post by: Gominalo on November 07, 2024, 06:24:58 pm
usually the backlight breaks down on this type of units.
If you shine a bright light on the front can you see the image a little ?
Benno

That has been checked by another person and told me that there's no image but i'll check by myself.
Thank you.
Title: Re: Industrial LCD display
Post by: Gominalo on November 07, 2024, 06:27:36 pm
the backlight board as 4 outputs on it, or 2 in parallel ? 

check if you see markings on it, who would help you   for voltages and control pins


t-con is not for backlight ...


do i see tdk  something  on the ccfl  board   can you show us photos or write the numbers

I supose that like others ccfl there are two tubes in series per side of the LCD that's why i have 4 connectors.

TDK S/N is: PCU-P235B

Thank you.
Title: Re: Industrial LCD display
Post by: dietert1 on November 07, 2024, 07:06:07 pm
Roughly a year ago i converted two old Samsung computer displays from CCFL to LED, using a kit (probably Chinese origin). After one of the displays got ready and was working well i ordered another kit and did the second one. One has to take apart the display anyway in order to fix the backlight, and the LED solution is much better: less energy consumption and less heat. Hope it will last some more years.

Regards, Dieter
Title: Re: Industrial LCD display
Post by: Gominalo on November 08, 2024, 09:26:50 am
I've identified a bad smd component, i think it is a diode.
Before it there's only one thing, the connector wich supplies 12v directly to it, the diode is not conducting anymore. Can anyone help me identifying?
It is located in the high voltage pcb for the ccfl backlight.

Thanks.
Title: Re: Industrial LCD display
Post by: inse on November 08, 2024, 10:55:42 am
“50“ is possibly a fuse, measure resistance across the capacitor below, it might give a hint why it blew (if it’s a fuse)
Title: Re: Industrial LCD display
Post by: coromonadalix on November 08, 2024, 09:18:00 pm
50 would be an inductance  way thicker than  the 202 resistor near it

give us the chip marking near them,  search datasheet   could give you something to work with