Tv lcd akai

Hello to all from Tom Arnold, WA6OVP

Subject: Repair of computer monitors or flat panel TV’s.

History:
Recently my wife's 27-inch AKAI (LCT21AS) 27-inch flat panel HDTV with DVD player quit working. Years ago, when I had an analog computer monitor quit operating; Joe Fadden WA6DDF had mentioned to me, that often computer monitor problems were caused by the monitor's power supply. Joe also said these power supply problems were often caused by failed electrolytic capacitors. Joe said he was able to fix many computer monitors by just changing all of the power supply electrolytic capacitors. Rather the fix that failed monitor, I just a bought a new one.

Symptoms:
The inoperative HDTV had been bought at COSTCO and had already been returned once to a COSTCO repair center for repairs. Cost to ship and insure the HDTV was 67 dollars. We received back a new HDTV set. Turn around time was over a month, with many long distance telephone calls being required. The new HDTV worked for about three months after it was received. When the returned HDTV failed, it trapped a DVD disc that had been left in the HDTV DVD player. The new HDTV failure symptoms were the same as the original HDTV failure. The red led indication would not change to green when the remotes power on button was pushed. There was no picture and no sound. The remote is required to operate the TV set.

Economics:
My wife's HDTV with internal DVD player was very expensive. Worse yet, the trapped DVD disc was the movie Flash Gorden Space Soldiers 1936. A local TV shop wanted 85 dollars to look at the failed HDTV; repairs were 75 dollars labor an hour plus parts. I quickly figured out that if I could fix the problem it would save a lot of time and money.

Internet Search:
I checked the Internet to determine if other AKAI owners had similar problems with their HDTV sets. There were lots of AKAI 27 inch and 32 inch HDTV set owners listing problems. Without exception all of the complaints concerned the HDTV power supply PC board and failed electrolytic capacitors.

General Internet Consensus:
Most of the AKAI HDTV sets worked just great and that many had been sold worldwide. There were some AKAI HDTV sets that did have power supply problems. Most of the AKAI HDTV set owners were not very pleased with either AKAI or the COSTCO response to the inoperative HDTV power supply problem.

Trouble Shooting:
All electrical power was removed from the HDTV set. The HDTV was placed face down on a workbench with a piece of cardboard to protect the display screen. The HDTV back panel cover was removed. There were many screws of several different sizes. The power supply PC board was separate from the rest of the set's components and was easily identified. The power supply PC board contained several different individual different voltage power supplies. Three electrolytic capacitors located on the PC board had obviously failed. The tops of these three capacitors were puffed out. Often when electrolytic capacitors fail they get over heated and the top of the capacitor is puffed out displaying an over pressurized appearance. The power supplies on the PC board were of the switching type. Switching type power supplies are also used in computer monitors to save money and weight.

Power Supply PC Board Removal:
The power supply PC board was mounted to the HDTV back panel with several screws. These screws were removed. There also several multi-pin connectors attached to the PC board. These connectors were numbered with a black felt marker to ensure correct reinstallation. The connectors were Hot-glued in place. A sharp knife was used to remove the hot glue. The connectors were removed.

Repair:
The three suspect failed capacitors were easily removed. The three capacitors were each 1000 ufd and rated at 16 working volts. The other power supply PC board electrolytic capacitors were visibly checked. Three new capacitors were installed, they were rated at 1000 ufd at 25 working volts. On the PC board the three electrolytic capacitors were in just one of the power supply circuits and were identified as EC18, EC19, and EC20.

The New Electrolytic capacitors:
These were low impedance / high reliability radial lead polarized aluminum capacitors, they have a plus and minus connection pins. Correct installation of any polarized capacitor is required. The three new electrolytic capacitors were specifically designed and rated for service in switching type power supply circuits. Switching type power supply electrolytic capacitors need to be both very robust and designed for use in high frequency circuits. General-purpose aluminum electrolytic capacitors should not be used in switching type power supplies, if capacitors designed for switching power supplies can be obtained.

Final Repair Steps:
The PC board was reinstalled without the electrical connectors to the PC board being hot glued. The HDTV back panel cover was refastened. Watched episodes one through five of Space Soldiers. It was well worth the time and three electrolytic capacitors to fix the problem. The repairs saved a lot of time and money. The repair was very simple and not the least challenging. It took longer to remove and then reinstall the HDTV back cover panel than it took to replace the three failed capacitors.


Safety:
These types of repairs should not be attempted without a complete understanding of the dangers involved with working on electrical equipment, especially working around power supplies and charged capacitors. Proper desoldiering and soldiering techniques need to be used.

Conclusions:
Flat screen computer monitors and TV sets do fail. Repairs of electronic equipment can be very expensive. When your computer monitor or flat screen TV does fail, you might consider a visible inspection of the equipments power supply. A simple repair might save you a lot of time and money.

Exactly right! TARNOLDSR's solution worked for me too. I replaced the 3 capacitors and the TV turns on again!

Thanks TARNOLDSR!

The solution of replacing capacitors works. These are just a bit more details, there are a total of 17 capacitors on the power board, when I looked at mine 6 had visible signs of failure. Also note that the capacitors can fail without the puffing of the tops. One had blown out the bottom and the top looked fine only because the capacitor was now angled and not straight up was there any visible indication it was gone. So, don't assume that capacitors are only bad if they show the puffed end.
From my perspective the capacitors are cheap and considering there are only 17 I decided to replace them all with premium quality capacitors. It will cost a little more (closer to $1 a piece instead of $0.50 for the cheap ones). So considering you have the TV apart you might as well swap all of them out and do so with better quality parts.
To assist those that are going to have to order the parts, the following is a list of the 17 capacitors you will need.
3 1000uF 16V High Temp Radial Capacitor
2 470uF 16V High Temp Radial Capacitor
2 470uF 35V High Temp Radial Capacitor 6 1000uF 35V High Temp Radial Capacitor 2 470uF 25V High Temp Radial Capacitor
2 1000uF 25V High Temp Radial Capacitor
That way you can get all the parts on hand before you bother opening up the TV set.
For those having trouble finding the parts, you can use Amazon.com and you will find them. Radio Shacks are not really a good source anymore as too many of them are dropping their support for parts and focusing on cell phone sales.
Also, for those that aren't as familiar with desoldering and soldering. Remember to get the right equipment, a desoldering iron or at the very least a desoldering pump is critical... also make sure you clean off the circuit board before you solder in the new parts, failure to do so will make it difficult to solder the new part in properly and a poorly attached new part will be just as pointless as the old broken part was.

I just wanted to say that tarnoldsr's response was absoltely on the money. I has the EXACT same problem and followed his advice and OMG... after I put it all back together and 1/2 expecting it not to work...BAM! it works like a dream now. Check the capacitors. If you replace them MAKE SURE that you put the longer capacitor lead into the + (positive) port, and the shorter lead and side with the - mark into the negative port. Failure to do so could do anything from shorting out the board for good, tripping a circuit breaker...or even worse. Good luck!

I cant thank you enough. i spent less than 8.50 on new parts at radio shack and i was totally amazed that it worked. so simple that even a caveman can do it.

Where did you guys find the caps? I could not find them at radioshack?

Genius!! Thanks Tarnoldsr, your solution worked! Easy AND cheap fix! You Rock!