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Old May 17, 2010, 12:59 PM
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Is it easy to change out the inverters?
I have a Samsung Syncmaster 205bw monitor that is really getting dark and wonder if putting in a new inverter will fix it.
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Old Oct 19, 2010, 07:54 PM
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Originally Posted by holdentogether View Post
Ok I also have the nasty Dafron V144-001 inverter board in my 30" LCD TV I see a lot of other people are having problems with these.

I didnt fix it but I fooled it and It was easy. On the 20 pin oz960 which is a ccfl controller I noticed that pin 10 was rising and staying well above 2.75v thresehold,( more like 3.75v) this will allow the Backlight to start up for a second or two then turn off. The reason for this is pin 9 is low allowing the oz960 to not monitor overcurrent on start up. then as pin 9 rises in voltage pin 10 should be falling in voltage, but mine doesnt. So an easy fix is to put a LED from pin 10 to ground This holds pin 10 to around 2.4v, normal operating voltage.

Let me know if it works for you

Doing this is at your own risk I believe a common fault with these is the Transformers but I tested mine and they seem ok well close enough he he

Cheers and good luck
Justin

This fix work great for me! A simple LED at PIN10 (+) to the ground and voilą!
My sceptre X30SV now working again since 1 day. All the transformers was in the range arround 950 ohms. Inverter board cost arround 120$, that's the money i saved with your fix. Wow, Thanks a lot!

Did you ever think to spead it on others forums? (fixya)
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Old Nov 03, 2010, 02:08 PM
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Squematic

Hi, I looking for the squematic to repair inverter Darfon V144 48 V1448.001/F,

somebody can to tell me where can i get?

Thanks a lot.
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Old Apr 28, 2011, 12:40 PM
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Originally Posted by holdentogether View Post
Ok I also have the nasty Dafron V144-001 inverter board in my 30" LCD TV I see a lot of other people are having problems with these.

I didnt fix it but I fooled it and It was easy. On the 20 pin oz960 which is a ccfl controller I noticed that pin 10 was rising and staying well above 2.75v thresehold,( more like 3.75v) this will allow the Backlight to start up for a second or two then turn off. The reason for this is pin 9 is low allowing the oz960 to not monitor overcurrent on start up. then as pin 9 rises in voltage pin 10 should be falling in voltage, but mine doesnt. So an easy fix is to put a LED from pin 10 to ground This holds pin 10 to around 2.4v, normal operating voltage.

Let me know if it works for you

Doing this is at your own risk I believe a common fault with these is the Transformers but I tested mine and they seem ok well close enough he he

Cheers and good luck
Justin
This is in reference to a very earlier post, but I wonder what will happen if I identify and isolate the faulty transformer on the circuitry, would there still be an over current or voltage - requiring limitation by the OZ960 or 964 on my lg inverter board.
Thanks for all the useful information on board it helps to move on despite the breakdowns. Cheers.
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Old Jun 27, 2011, 12:05 PM
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Felt like sharing!

This seems to be the ultimate DIY inverter repair thread, so I thought my experiences were best recorded here possibly to be of use to others.

My lcd model is an HP HSTND-3l02 aka lc3040n 30 inch. I found it in the rain, disassembled, on the side of the road. Someone had obviously taken a crack at DIY themselves before brashly throwing it away (no doubt in anger... the working parts are worth good money!).

At first the unit would not turn on at all, no lights, just hissing when plugged in. I assumed the power supply was shot and immediately ordered a replacement. A day or two of drying later and the power supply had revived! I canceled the power supply order and realized that although the power supply appeared to be working, the screen would only stay on for 3-5 minutes then only turn on for a few seconds or so until I let the components cool down. Google pointed to the inverter board.

My lcd like many others has the infamous Darfon v 144.001 board and $150 for a replacement (lcdparts.com) is simply RIDICULOUS!!!!! I had to fix the board on my own, so I disassembled and broke out my multimeter. In the end, all the probing told me mostly nothing, except that the testable components appeared the same, and nothing was visibly messed up. Only one of the cctv tubes would flicker before the screen would go totally black. I knew which one it was, and therefore which transformer circuit was the problem. I observed while the screen failed and saw arcing on the primary transformer lead!!! There was grit and visible "gunk" on the transformers and their leads, which I cleaned off. This helped but did not entirely solve the problem. The arc simply got smaller... There was a slight "burr" or groove which was enabling the arcing. I then filed that down with a tiny round file I had and now the problem is gone.

This is my first crack at an LCD. The sum-up seems that grit/dirt and oxidation can accumulate on the inverter high voltage parts over time, and that occasionally cleaning/filing these anomalies will restore current flow where it is supposed to go. I got lucky! Hopefully you will to!

#UPDATE#

Ok, so I didn't think I would REALLY get out that easy! A day or so after writing this, the problems re-emerged, but thankfully just a repeat of the same issue and not something new. The arcs were much smaller this time, but on the same lead. Occasionally the screen would die without any visible arcs at all, but the rattlesnake sound was still there, use your ears! So seeing as the problem was one of a bad solder joint (which I knew by comparing multimeter readings on all the transformers and capacitors and also by considering the last fix described above was temporarily successful), I broke out the heat gun (soldering irons and I don't see eye to eye) applied pressure to the corner of the transformer nearest the faulty arcing lead and re-melted the solder (660F ~30sec NEVER APPLY HEATGUN HEAT WITHOUT CONSTANT MOTION!). I am happy to report that at the time being everything is working! My new theory is this has to do not with oxidation and detritus (although that certainly sped up the process), but rather out-gassing of flux from the solder accelerated by the heat of the transformers, oh and poor solder/soldering to begin with! As the flux boils away tiny pockets of air are created that can interfere/break the solder joint. Obviously if the solder were used correctly to hold two leads directly against one another, even if that solder became full of microscopic air holes, it would continue to do it's job of holding the two conductive metals together. If you have tested the transformers and capacitors and they appear to be good, try looking for a bad joint, the HV parts will hiss and arc in that case and should be pretty easy to spot. If I were at my wits end I would try baking the whole inverter board. If it is a solder joint causing the problem, this will likely fix it. If you are seriously considering doing that check youtube first on xbox360/ps3 reflow in the oven. I hope this helps someone!

Update#2

Same problems appeared again! The permanent solution seems pretty clear, remove the crappy solder completely and replace it. Break out your soldering iron and fix it right. I hope this isn't against the rules, but I found I site detailing the fix to exactly this problem. Although he is replacing a transformer, he mentions at the end of the article that the other transformers had similar troubles after his successful replacement of one of them, and that re-soldering has fixed the problem presumably for the life of the set.

http://www.threewestcreative.com/389...ight-inverter/

Update#3

I had fiddled with the power cable to the inverter board so many times that I had convinced myself it was part of the problem. Although continuity checked out, I set out to fix what wasn't broken anyway. If you have a similar inverter problem, you may notice that adjusting that power cable may get your inverter board to power on again, sometimes staying on and appearing "fixed" for some time. This may lead you to theorize some bizzare air gap transformer increasing the voltage causing increased arcing and decreased amperage, and concluding that the fault lay in the cable that connected the psu and inverter. You would likely be wrong, as I was wrong.

Ultimately I fixed this tv by following the instructions in the link I left in the "UPDATE#2" section above. De-soldering braid, some solder, and an iron is all you need. In my case the bad joint was obvious. Although comparing multimeter readings across the transformers is mostly effective to find the bad egg, in my case it absolutely was not. I was wondering why a transformer of this kind would ever go bad.... crazy metal fatigue caused by electron flow? Transformers are magical, but they are also simple and not prone to many failures. I bet 9 out of 10 times these transformers are absolutely fine, they just need to be desoldered and resoldered. Good news for us! Also I SUCK at soldering and this was a piece of cake. Just remember that the solder will magically be attracted towards the soldering iron, so put the iron right behind where you want the solder to end up and it will go there. Thanks to everyone who contributed to this thread, and the gentleman whose testimonial and tutorial got me to put it all together.
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Old Aug 28, 2011, 11:03 PM
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WhaT TYPE OF led

hI i WIRED THE LED TO TERMINAL 10 AND Ground TO TERMINAL 6. The screen went on momentarily and then went black. What type of LED should I use. I used one I had laying around but it didn't work. Please help
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Old Sep 20, 2011, 01:13 PM
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Originally Posted by chumbini View Post
hI i WIRED THE LED TO TERMINAL 10 AND Ground TO TERMINAL 6. The screen went on momentarily and then went black. What type of LED should I use. I used one I had laying around but it didn't work. Please help
I just used a 47ohm 1/2watt resistor, that held pin 10 to 1.88volts.

I started with a 100ohm res but that only held pin 10 to 3.11volts, so it still shut off the backlight.

A res with a value between 47 and 100 ohms that would hold the voltage of pin 10 to about 2.44 volts would probably be better (?).

It has been running for about 40 min now to test, hopefully it will last awhile during normal use.

I still need to replace one of the transformers on the inverter board and one of the CCFL bulbs.

Anyway, here are the links I plan to use to order the parts I need:

http://www.ccflwarehouse.com/30x65fuspcc.html

http://www.tvparts-online.com/index....products_id=65

Anyone know if these are the correct parts that will work with the LT30HV? (Hopefully before I go and order them in the next few days )

Later,
Jay
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Old Oct 24, 2011, 10:53 AM
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My story of this board.

Quote:
Originally Posted by chumbini View Post
hI i WIRED THE LED TO TERMINAL 10 AND Ground TO TERMINAL 6. The screen went on momentarily and then went black. What type of LED should I use. I used one I had laying around but it didn't work. Please help
I also found my sceptre x30sv nagaIII on the side of the road in the rain. Was another failed attempt by a fellow DIY'er. I dried it out and inspected the entire tv. The power supply was new and several of the screws were missing.

After serching the net looking for causes of this tv to fail, I found this great forum. Of all things this thread helped me the most. I first found my original Darfon doard was just bad, it didnt even flash the backlight. After testing I was getting no power to the OZ960chip and all the fuses were ok. I really didnt want to search any longer for parts so I purchased a new board. $70 after shipping from TV PARTS Fast.

That board worked fine for about a week, then it started flashing the backlight. So instead of the hassle of trying to get a new board I went back to work. I tried the mod with the led. that didnt do it. As I was testing pin 17 the backlight remained on until I pulled the meter off. I know the meter uses trace power to test circuits, so I figured something was up with the voltage sniffing circuit. That sent me back to the backlight inverter transformers. There is was, one of the dang new transformers on the board went bad. It tested a third higher in resistance than any of the others. When I got the new board I had to power it up several times before the tv worked in the first place. So it could have been bad from the start. The best part is I have a whole bunch of those on my original board. The tv is back up and has been alive for over a week now and everything seems fine now. I hope that this can help somehow.
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Old Nov 24, 2011, 07:17 AM
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I do not know good English are from Romania and I have this problem myself. I read here is true, everything is going ok, but no one LED must be specified as Matt and not transparent to the newer generation does not work. Use LED mat (I used matte red LED) (LED + to pin 10) LED - ground. My TV is SINUDYNE Model 30x02. I stuck the pin 10 and ground LED and found the problem in the mid-see LCD shade blue background and a horizontal tube does not work, I opened a 4009A inverter winding is burned. I mounted inverter at the bottom of the LCD to not be visible shadow. Now I order that inverter 4009A and to try to see if they work without LED.
http://www.ebay.com/itm/4009A-LCD-In...-/150478476653

Thanks for all indications.
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Old Jul 27, 2012, 01:05 PM
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Originally Posted by arniewrx View Post
Hi, Just in case any of you are still stuck with no backlights..
Clearly you are more experienced than I in these matters but I thought I'd share how I fixed my inverter board.

I set my multimeter to 200k and put the probes each side of every transformer, measuring the top two pins and bottom two pins.

Every reading barring the bottom pair on the second transformer gave a reading of 1.0. The bottom pair on the second transformer gave 0.5 so I replaced it with another transformer a spare board I bought on eBay and it worked great.

Have I done this safely?

Regards
Phill.
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Old Dec 12, 2012, 10:31 AM
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Hi there,
I had the same issue on my TV an the desribed workaround works fine! I put the 47 Ohm resistor between pin 10 and ground, and the picture will be stable enduring.

My question nevertheless:
Is this solution finally useful rather what is the primordial failure in this case?

If not to do and the solution is right - so much better.

Thanks in advance.
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Old Feb 07, 2013, 07:47 PM
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Update

It has now been over a year and this tv is still kicking it. The OZ960 chip and mostly the transformers are the problem with this tv. I use this tv in my garage and the weather doesnt seem the bother it. High humidity.
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Old Aug 10, 2013, 11:26 AM
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Could anyone help with this inverter from a Dynex 46" TV?
It's a Darfon V291-5XX
4H+V2918.061 /B
It uses an OZ9937GN chip
link to pic http://www.ccfloffer.com/bookpic/01/4H_V2918.061_B1.jpg

The backlight comes on for 10 to 30 seconds then shuts off.
Power supply seems to be supplying proper voltage.
It could be one or more of the bulbs. If they're on the way out the inverter may not be sensing the correct voltage. They all do light for that 10 to 30 seconds.
It could be the inverter board. Maybe the OZ9937 chip?
It could also be the main logic board not sending the correct signal to keep the lights on. There are two wires going to the inverter that aren't power. Disconnecting them gives the same 10 to 30 second results. So either the signal isn't being sent or the sensing circuit isn't working on the inverter or the bulbs are bad.

Would anyone know if the inverter needs a signal to stay lit? Can it be bypassed? That might eliminate the main board.
Can the bulb sensing circuit be bypassed?

Any help would be appreciated.
Thanks
davidk
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