Question about Akai PT4298HD Rear Projection Television

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Akai large screen T.V. color problems

Just yesterday our TV started having troubles, almost like tracers of some sort. For instance, when there is a face on the screen, next to it will be an outline of that face in blue. When the kids played video games the same thing happened. There is double of everything but it's only an outline, located an inch or two over from the origional picture and in blue. Does this mean my color os going out? Is there anything I can do to check it before having to pay to take it in. I'm not a TV mechanic in annnny way. Thanks a bunch!

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  • Anonymous Mar 01, 2008

    me yoo

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I have a similar problem with my AKAI 42 inch plasma, now my whole tv is purple. all you can do is contact akai warranty and have a service provider come out. but let me tell you, it is not an easy process if the service provider cannot help you. after the service provider told me that my tv was a goner. it took me two months to get a box to then send the tv back to an akai service center. now i have to wait a month or so, before i get it back. i wish you good luck.

Posted on Mar 03, 2008

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94 mercury tracer no spark


Crank sensor or coil. Rare instances, could be the ECM or wiring.

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My name is Rohan , Im an Electronic Technician, I have a LG 34 LH 20 inch LCD...


This is the basic guide that can be applied to most LCD flat panel TV.
By Bud Martin
First, try unplugging it from the outlet for about an hour to see if the TV will reset itself since the minute the TV is plugged into the wall, the power supply and processor will be running 24/7 and the EPROM can get corrupted by spikes and surges. Try using good quality surge suppressor to see if it will help if it happen often.
Look for burnt brown hot spots on the circuit boards, capacitors with leaking/bulging top or seals. Loose wires and connectors. Blown fuses.
Notes: We are dealing with high voltage that can kill you! so if you are not sure what you are doing, please have it fixed by the pro that has proper tools and safety equipment. Try to use GFI outlet and isolation transformer when work around the TV set and DO NOT DEFEAT THE GROUND PIN OF THE OUTLET/POWER CORD.

1) The power supply module (There are 4 regulated output voltages:- Standby 5vdc, switched 5vdc, 12~16vdc, and 24vdc).

The power supply converts the 120/230vac 50/60Hz into DC, then the high frequency (50~100kHz) switching circuits convert it back to AC but at high frequency which allows the power supply to use smaller and much lighter weight transformers (Ferrite core instead of heavy iron core), then this high frequency AC voltage is fed to the rectifier Diodes to get the DC output and filtered by DC filter capacitors that must have low ESR (Equivalent Series Resistance), if general purpose electrolytic caps are use, they will fail within a year or less due to high ESR.

The power supply has Standby 5vdc (5VSB, this is a MUST have before anything else will work, when this voltage is not present, there will be no any indicator light on the front panel) which is always on the minute the TV is plugged into the AC outlet, so it is on 24/7 and that is why the power supply will fail even though you may use the a TV not very often. It will see all the voltage spikes and surges 24/7.
This 5vdc is used to power the Processor and the Infrared remote receiver module which will be waiting for the command from the remote control or from the power switch, when the Power on command is received, the Processor will send the turn on signal (3.3~5vdc) to the power supply module (PSON pin) to the switch on the main 5vdc for the rest of the logic and Tuner circuits, 12~16vdc for the sound amplifiers (mostly Class D amplifier for efficiency and small size) and for the T-CON board (interface board between the LCD panel, some T-CON uses 5vdc, and the Logic board), and 24vdc for the Back lights inverter board (if there is no 24vdc then no back light).
Common failures:
Blown main AC fuse due to shorted out Diodes, transistors.
Bad capacitors leaking or bulging tops:
Shorted Diodes, transistors in the DC output side.

Testing the power supply output with dummy load:
24vdc testing: Disconnect the wires that go to the inverter board first. You can use two #1157 (using both Lo & Hi filaments by paralleling them at the base) car light bulbs connected in series so they can handle the 24vdc, this will put light load (about 70w) on the 24vdc output, the voltage out should be steady at 24vdc (+/-2v), if not, the power supply has regulation problem.
12vdc testing: disconnect the 12vdc TV load from the power supply board and attach one #1157 (using just the Hi filament), the 12vdc output should stay at 12v (+/-1v), if not, the power supply has regulation problem.

You should see the lamps go on when the TV power switch is ON and go OFF when the TV is powered OFF.

2) Main Logic board (It has Processor, Tuner, Sound Processor, Sources selector, Power amplifiers for speakers, interface port to the T-CON board for pictures).
This logic board sends out the turn on signals (3.3~5vdc) to turn on the rest of the Power supply module (Switched main 5vdc, 12~16vdc, and 24vdc), Inverter backlight ON (if no back light on command then there is no back lights),
Logic board supplies 5 or 12vdc to T-CON board B+ pin through switched transistor if T-CON board does not get the voltage from the logic board, you will get white/gray glowing screen without pictures.
Back lights Dimming (PWM) control signal.

3) Back lights Inverter board. Its job is to provide the drive voltage for the CCFL (Cold Cathode Fluorescent Lamp) to give white light for the screen.
This board is fed by the switched 24vdc (VBL) from the power supply module, it also get the Back lights on (BL on) control signal and the Dimming (Dim/PWM/) signal from the logic board. So for it to work, it needs 24vdc and the BL_ON signal.
Common failures:
Blown surface mounted fuses due to shorted transistors/ICs, Transformers.
Bad capacitors.

4) The T-CON (Timing Control or LCD controller) board (on the LCD panel assembly). It transfer the universal image signal of TTL and LVDS signal to specific TFT (Thin Film Transistor) LCD.
This is the interface board that talks to the Logic board and the LCD panel to produce pictures on the screen. White/gray glowing screen when it fails or not getting the voltage from the logic board (the 5 or 12vdc is supplied by switched transistor on the logic board). Notes: T-CON board is mounted under the metal cover shield.
Common failures:
Scrambled pictures, Lines, multiple pictures, color smears/blotches, rolling pictures after warm up.
Blown surface mounted fuse.
No pictures, very dark screen almost like there is no backlights.

5) LCD panel assembly to display pictures. The LCD pixels will block or unblock the back lights from the back of the panel to the front of the panel. This is the most expensive part of the TV, it will be more than the TV is worth.

As you can see, you must have all the above Voltages and signals for the TV to work properly. This may help you narrowing down the bad modules instead of buying the wrong module just to find out later that it did not solve the problem. Hope this will help you out.

Sound problem:
Let verify first to narrow down to where the problem can be. First, check the on screen sound set up menu to make sure the speakers are not set to OFF. If the setting is OK, then attach the powered PC speakers to the Audio Line out RCA jacks to see if you can get the sound there, if you do, then the problem can be in the power amp circuits, if you do not get the sound at RCA jacks, then the problem can be in the sound processor circuit. To get the sound repair, it can be from $150 and up, so if you can put up with using the good set of Powered PC speakers which actually give better sound than the tiny speakers inside the TV, I would keep using it that way, you may want to find out if the on screen sound setup will allow you to set the audio line out to be VARIABLE which means the sound output feeding the PC speakers can be varied using the TV remote control, then all you have to do is to set the PC volume to about half way up and set the TV volume to what ever you want.

Inverter board connector: you can also see the Fuse 4A/160V
http://i.fixya.nethttp://i.fixya.net13ca788.jpg
Power supply connector:
http://i.fixya.nethttp://i.fixya.net78e0d9a.jpg

http://i.fixya.nethttp://i.fixya.net2fc510f.jpg
T-CON board: (metal cover shielding is removed to show the bd.)
http://i.fixya.nethttp://i.fixya.net0b5367e.jpg
Inverter board:
http://i.fixya.nethttp://i.fixya.netaf0a695.jpg
Logic board:
http://i.fixya.nethttp://i.fixya.net4bd108e.jpg
T-CON board is dead, no power or blown fuse on the board, screen turns WHITE, must see it in darkened room, otherwise you may mistaken it for failed backlight.
http://i.fixya.nethttp://i.fixya.net3a91b68.jpg
Bad T-CON board after warm up, you get lines, multiple pictures, strange colors blotches, etc.
http://i.fixya.nethttp://i.fixya.netd3cf194.jpg
Bad caps (leaking/bulging tops). Make sure to replace bad cap with good cap such as PANASONIC FM or FC series , they are Low ESR (Equivalent Series Resistance) which is a must for switch mode power supply, and 105c rating. Do not use generic electrolytic caps.
http://en.wikipedia.org/wiki/Capacitor_plague

http://i.fixya.nethttp://i.fixya.netbe827ec.jpg
Bad T-CON board or power supply problem

http://i.fixya.nethttp://i.fixya.net034e1db.jpg

24vdc power supply output testing using two 12vdc car lamps in series.

http://i.fixya.nethttp://i.fixya.net4f2929c.jpg
Bad LCD panel, vertical 1~2 pixel wide lines
http://i.fixya.nethttp://i.fixya.net28e50c1.jpg
Failed TV and Monitors: http://s807.photobucket.com/albums/yy352/budm

Free service manuals: www.elektrotanya.com

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Cannot connect to facebook as of yesterday. States website not available. All other sites no problem.


face book is a site that over the past month or more has been having all sorts of problems
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Vizio 47" screen won't stay on


Your Vizio TV may be exhibiting symptoms of power supply trouble even though it is quite new.

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Akai 32" wide screen lcd tv/dvd combo LCT3201AD


This may be an instance were the idea was great but the execution wasn't thought out. I've heard of several related problems that may be related. Both the TV and the DVD player tend to produce heat, not in great abundance, but together a sizable amount of heat. The power supply may have been ample for the TV at first but with the addition of the DVD player was not able to handle the extra load. If still under warranty you're all set. If not you might call Akai and see what they might be able to do for you.

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1 Answer

I have a Vizio 42 in LCD, model VO420E. The TV makes a loud screeching noise, the screen goes crazy and then shuts off and starts again. There sometimes is a pop. Other times the TV just makes the POP...


Hi well what's happening is that the "Protection circuitry" in the SMPSU has/is detecting a potentially catastrophic fault, and to stop a fire AND EXPLOSION OR INDEED BOTH, IS ATTEMPTING TO SHUT THE SET DOWN FOR SAFETY REASONS, HOWEVER AFTER IT SHUTS DOWN, THE "FAULT" APPEARS TO "GO" AND THEN THE SMPSU STARTS UP AGAIN , ONLY TO DETECT THE FAULT AND SO ON... USUALLY ENDLESSLY OR UNTIL COMPLETE FAILURE OCCURS.
What to do, well in all reality DIY is NOT feasible unless one has LOTS of experience, test gear, tools, isolation transformer, and a service manual. So, contact the local or head office from VIZO, ask them for a referral to an authorised service center, hopefully a local one? in any event, make face to face contact here and ONLY ask first for a "Quote" as to prospective costings and go from there, this way at least you can make up your mind as to repair or replace?

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1 Answer

When I leave my TV plugged in too long the color goes out and everything is red. What causes this?


Depending on the age of the TV it sounds like its over heating after being on for a certain amount of time. If you can hear the tv start to make different noises/get louder over time then it would confirm the over heating. If it is over heating you can attempt to remove the back panel, or place the tv in a more ventilated area, or even place a little fan blowing into the back of it. A lot of large TV's can have over heating problems due to the large screen.

Hope this helped.

Feb 07, 2011 | Akai PT5492S 54" Rear Projection...

1 Answer

I have a large sony hd read projection / a few days ago - i started getting faint green lines that are arched - higher in the center - symmetrical, an about 1.5 inches apart - a few times , the tv has...


All projection TV sets have two very common problems. One is convergence ( 3D/Warped video) the other is CRT fluid ( Dull Video). Here are more details and solutions for both.

Common Problem #1) Convergence has gone out

Projection TV sets need to have all three colors - RED - BLUE - GREEN - lined up correctly on the screen in order for the video to look normal. When its out of alignment the video will look 3D, wavy, distorted, etc. Most of the time you just need to adjust your convergence in the TV menu. If you cannot adjust it in the menu - then your convergence is broken and needs to be repaired.

This is a very common failure on these projection sets and a fairly simple DIY fix. All projection sets including Samsung, RCA, Sony, Philip Magnavox, Panasonic, Pioneer, Akai, GE, JVC, Toshiba, and others at some point will have the same problem.

Common Symptoms include....

  • Screen looks 3D
  • Colors don't line up
  • One or more colors can't be adjusted when using the convergence menu.
  • Screen is bowed or warped.
  • TV shuts off after powering on. Power light will blink. TV may also make a chirping noise.
Here are some pics of convergence problems.


7859b01.jpg

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Common Problem #2) CRT Fluid is Cloudy

Projection TV tubes have a liquid coolant that is used to keep them from overheating. After many years the coolant in the blue and green tubes will become cloudy and cause the screen to look dull, red/orange, etc. You may even see halos around images.

Picture of a set that needs the fluid changed.

578ba6c.jpg
TV set after fluid change

65af323.jpg

69189a5.pngSOLUTION

You can see some more examples and find a fix using this link on Fixya http://www.fixya.com/support/r2861467-solution_video_looking_whiteish_dull

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2 Answers

I have 55" akai rear


You are going to have to look for open PICO fuses along with bad bias resistors close to the ic's. You should have close to +27 and -27 volts of B+ on the chips to start with. That will ensure the fuses are good. Then trouble shoot the convergence circuit from there.

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