2 seconds until black - please help before I blow something up!

[frosty3907]

Howdy all,

Have a backlight assembly with inverters from a monitor I've long since lost the other parts for but I"m trying to get the backlights going properly to turn it into a coffee table

I'm powering via a 24v 9A adapter (was from the monitor originally I believe) - applying 3.7v to on/off pin via a liion18650 causes the backlights to all light up for two seconds, then off.

I located the protection IC OZ9982GN shown in close up photo attached, couldn't find a useful data sheet on it, tried pulling pin 1 up and applying 5v but that didn't help. Next thing I was going to try doing was shorting the ceramic caps around it.

All bulbs look fine and resistance from the transformers measures uniform.

Any help mucho appreciated!

Thanks!

[kasfamily]

Re: 2 seconds until black - please help before I blow something up!

Please show PDF OZ9982GN

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

I couldn't find one.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

I did find this though
http://histar.en.seekic.com/product/.../OZ9982GN.html

If it helps?

[budm]

Re: 2 seconds until black - please help before I blow something up!

So are you supplying both master and salve boards with 24V? I see the slave has no 24V the connector that looks like it was removed.
https://www.badcaps.net/forum/attach...2&d=1410769778
The master also does not have the FFC (Flat Flexible Cable) between the master and slave connected either.
https://www.badcaps.net/forum/attach...1&d=1410769778

There are two brown connectors on the master inverter, do both of them have FFC connected to them?

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

Hi, I was previously trying with 24v to both boards with the exact same results. Also had the FFC connected, was just removed for the photos.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

Although I should note that I don't have the original logic or power boards installed anymore. I have the master and slave inverter and the t-con board.
I don't think I have the other boards anymore.

[budm]

Re: 2 seconds until black - please help before I blow something up!

Ah, so you have PS_ON for forcing on, and the BL_ON for the backlights. How about the dimming control line, some will need this signal? I cannot see well if it has both PWM Dimming (Variable PW from 10%~90% @ around 200Hz) and Analog dimming (0~5V). You can look up the panel spec sheet to get the details.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

Yes there are no control signals being sent.. The FCC cable connectors are marked:

NA2
GND
NB2
GND
VSENS
STATUS
FBML
STB
FBS
A-DIM
24V-ON


DIM-SEL
NC
PWM-SYNC
SELECTION

the on/off I'm using is on the 24v connector though.

I don't remember what panel it was..
The inverter is pw-cw42bo(or 0)-m(t) rev 0.7

lc420wx5

[budm]

Re: 2 seconds until black - please help before I blow something up!

See post 11.

[budm]

Re: 2 seconds until black - please help before I blow something up!

OK found the spec sheet (not sure if it is exact match or not), have to read the details later.
BTW, the inveter board P/N's are 6632L-0371E (MASTER), 6632L-0372E (SLAVE)
http://www.shopjimmy.com/lg-6632l-03...ter-master.htm
http://www.shopjimmy.com/lg-6632l-03...rter-slave.htm

See page 11.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

This looks super useful but I'm not seeing anything immediately wrong or explaining the shut down?

E: also thanks for your help so far

[budm]

Re: 2 seconds until black - please help before I blow something up!

Look at pin 14 STATUS to see if it is >3V (normal), or <0.7V for abnormal condition.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

3.09v

[budm]

Re: 2 seconds until black - please help before I blow something up!

Boy, that does not make since it does not sense any error to cause the status pin to go low but yet the backlights will not stay on. I think we may be missing something some where. Before you trying to convert this into a light table, did the backlights stay on?

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

Last time I used this screen was many years ago, it worked fine but I cracked the LCD while moving, I've since kept it in storage with the intent of using the backlights for something.

[budm]

Re: 2 seconds until black - please help before I blow something up!

OK, so I think it wants the signal, which one I am not sure at this point as to what it is.
BTW, that 24VDC power supply you are using, can you monitor its output voltage when the lamps flash on for 2 seconds to see if it dips down below 24V? You may have to try a couple of times if your meter is not fast enough to catch the drops.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

Drops to around 18v at the instant it turns on but immediately goes back to 23.5v for the two seconds and after.

Pretty sure it's the same adapter that came with the monitor so it should be in spec.

[frosty3907]

Re: 2 seconds until black - please help before I blow something up!

Is there any point replacing the large caps? Think they're 35v 470uf - I have three 50v 470uf laying around but not four, is mixing different voltage caps a bad idea?

[budm]

Re: 2 seconds until black - please help before I blow something up!

If your slow meter can see 18V, it is more likely to be even lower, the spec for the panel is 22.8V,page 7