Re: Dell ST2410b Backlight Shuts Off
Hi Niek,
This symptom you have described is usually the capacitors. I believe the only proper way to measure the capacitors is with an ESR meter. Degradation on capacitors aren't necessarily visually apparent. The most common visual indicator of bad capacitors are the bulging on the tops.
Really, all other tests bypassing the capacitors in my opinion is a waste of time. First make sure the capacitors are good (or replace them). If that doesn't fix it then other avenues could be explored...
Hope that hel...
uengin
Member
Last Activity: 05-30-2015, 05:17 AM
Joined: 01-30-2014
Location: Brisbane
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Re: Dell ST2410b Backlight Shuts Off
Does anyone have any ideas on where I might be able get the ribbon cable I posted just before?
Label: P-TWO AWM 20696 E221612-S 80C 30V VW-1
It's 30 lines/"pins"
ThanksLeave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Sorry guys, work, life etc getting in the way...
Anyhow, even though the soldering looks bad (with the board being browned and all) I think it might not be my current problem after all. It seems like somewhere between me ordering the inverter IC and soldering it on, the LCD (LVDS?) ribbon cable has ripped. Which would probably explain the symptoms I am getting for the time being.
Now need to find and order that!...Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
I'm ashamed of the desoldering to be honest. I'll manage a shot and upload it.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Hey people,
Chips came. I got impatient with the SMD work, ran it a bit too hot... Board browned out and I heard crackling sounds while desoldering. When I replaced it with the new chip and powered it on: power LED started to blink. GRRRR.
I've ran out of patience but does anyone still think it's work trying to save this board?
By the way I have 4 extra OZ9933 chips. I'll sell it out for about $5 each if anybody is interested?Leave a comment:
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Re: LG Flatron L194WT inverter board; light flicker
Ok, so there is a DIM line. Question is is it active high or active low? Pulling it high seems to me it will make it dim out? No?...Leave a comment:
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Re: LG Flatron L194WT inverter board; light flicker
Ok, here's the photos. I don't know if it's the lighting or what, had so much trouble getting focussed images. Probably because I'm using a Nikon, I much prefer the Canons... Anyway, that's another story....Leave a comment:
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Re: LG Flatron L194WT inverter board; light flicker
yeah, photos coming soon
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LG Flatron L194WT inverter board; light flicker
Hello everyone,
Here I have the board only from a an LG Flatron L194WT. When a friend gave this to me because it was playing up and I didn't have time to fix it nor did I want it taking up space, so I just took the inverter board and tossed it out. So, for a learning experience I'd like to fix it.
Tied BL_ON high to 5V rail. Hook it up to known good CCFLs. CCFL light flickers and slightly fainted. Capacitors are SAMXON, no bulging evident but not always have to bulging. Voltage rails are all good.
I know I can test component, but I don't want to start... -
Re: Advice/suggestions on a "dead" Samsung 2693HM
There's not a whole lot you can do with (or rather lack of) your resources and equipment.
But, seriously, you shouldn't just dump it, consider giving it away as selldoor suggested as a lot of good parts are just going to be landfill.
Good luck with the intermittent faults there, in my experience they usually get worse not better.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Davi.p, you, budm and others who have contributed have been most helpful. Your suggestions, experience or otherwise have been an experience for me therefore I really appreciate it. Thank you all.
As for the final result, I have ordered several OZ9933GN ICs (just incase the first one I put in goes bad because of another fault in the cirsuit that we have not identified yet). I am waiting for the ICs to arrive and will let you know when the replacement is done and what the results are.
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Re: Dell ST2410b Backlight Shuts Off
Ok, I'll check if the ENA pin on the chip is high, if so, inverter IC needs replacement.
I'd like to thank everyone that contributed and gave their suggestions. I think I am going to love this forum and hope I can contribute to the members here and give assistance to others as well as I get more and more experienced.Last edited by uengin; 02-10-2014, 04:44 PM.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Could you correct me if I am wrong; The inverter IC is supposed to take care of oscillating the gates on the mosfets to switch them on and off causing change in currents in the primary coil of the CCFL transformer thereby creating high voltages on the secondary of the same transformer, lighting up the CCFL's?
So I tested those pins, and they are all in a "high" state. About 3 volts to be exact. All pins, 6, 8, 9, and 10.
I wanted to make sure that the input pin PWM was indeed receiving a PWM, and it is....Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Ok, I was impatient and tested the voltage across the primary of the CCFL transformers with a multimeter, then hooked up my scope. 0V and no activity, respectively.
Tested pin 11 got 5V.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Ahaa! The Asus VE205 has the identical inverter and power board as the Dell. That'll be handy to know when chasing down parts, ey? Thanks again for the selldoor.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
That'll be very helpful, thanks. At least there's some labels to those pins....Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Sorry, what did you mean by "Put it of 7V and go for sure.."?
I have removed that zener diode and hooked it all up. There's a full image on the LCD. BL_ON about 2.5V but still no light. So I disconnected the the BL_ON from the Video board and routed 3.2V from the Power line in to the BL_ON for the slim chance that it may require TTL logic levels. Still no light.
Should I check the waveform being fed in to the output transformers to make sure there is activity on the output stage? Do you know what...Last edited by uengin; 02-09-2014, 05:51 PM.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
The datasheet is hard to come by. I've found out its O2micro. It's an OZ9933GN. Any ideas where to find the datasheet?Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
Ok Guys, I think you might be spot on the ball with the Zener. [LIST]Removed JW13 and measured the capacitor voltage: 5V more or less.[/LIST][LIST]Just to rule it out or rule it in, I removed the zener and tested the voltage across the 10ohm resistor; it had (I think) 0.8V drop across it[/LIST]
Do I have to replace the zener? Do you think it failed as a result of another failure in the circuit? How do I know the specs to replace the zener with? It was reverse biased (it seems) so the reverse bias break down voltage is important,...Last edited by uengin; 02-09-2014, 01:23 AM.Leave a comment:
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Re: Dell ST2410b Backlight Shuts Off
budm, the resistor is the one I specified in a previous post, quoted below....Leave a comment:
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