Question about Akai PT4298HD Rear Projection Television

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Coolant leak and possibly short fuse problem on CRT RPTV

After doing the optical focus, I stupidly took the cover of the blue CRT off, forgetting about the coolant. Well, by the next day, a little had seeped out because I didn't screw it back down tightly enough (rectified), this dripped onto the convergence board, shorting it out I assume.

I cleaned all of the coolant (none had dripped farther than the convergence board, and there wasn't lots of it around). I have a new convergence board on the way, but I'm working about fuse problems on the power supply. I've tried unplugging the convergence board's power and turning the tv on, I still get no sound or picture and the blinking timer light up front.

But I don't even know what to look for on the power supply board. Are these fuses like on your car that can be unplugged, or switches like in a house? Will I need to do some soldering? I'm prepared to buy a solder, multimeter, service manual, etc. to try to fix this, as it's all cheaper than buying a replacement. If I need to take the power supply out to do some soldering, what should I be careful about? Will the PS just unscrew like the convergence board? I know tvs can hold deadly electrical charges, so I'm worried about that.

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Where ca i find a gasket for crt tube on assambly unit i got a pitch in the gasket ball i was told to use high temp b26 silicone over to glue the small hole i´m having hard time to find this gasket anybody knows

Posted on Nov 14, 2008

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Well I have work on many set, but I must say I have not work on an Akai but I think this set is much like the Apex and the PS may have a fusible resistor open. Second I have changed many of CRT fluids, but I have found that changing the gasket will cause leaks to cease. If you get the power supply out check the resistors and fuses. This sounds like your problem, but first I would make sure leak is taken care of, because if not you've wasted a good convergence board.

Posted on Mar 19, 2008

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1 Answer

Pro-710 clean front screen and crt


If the pic on your CRT RPTV is bleary, its front viewscreen is not the problem, and no, your set is not worn out even tho it really looks that way.
The solution is that the internal optics need to be cleaned, due to the high voltage inherent in CRT use. Remember how your old, thick computer monitor would get incredibly dusty on its face? That's because of the HV ionizing all nearby particulates and charging them with static cling. They then drift to and deposit themselves directly upon the closest smooth surface - in the case of CRT computer monitors, the face of the monitor. In the case of CRT RPTVs, the mirror and lenses. In other words, at certain very critical points on your 28 surface optical chain that comprises the CRT RPTV's projection light path.
Optics cleaning should happen once a year without fail, otherwise you're really not getting your money's worth out of your multi-thousand dollar set. And CRT HD ready RPTVs are classics, with 20 year service lives.
On some units only 4 surfaces need to be cleaned, like Mit. On others, like Pioneer, 10 of the 28 surfaces need to be cleaned.
But be very careful, these lens surfaces are made of very soft, vulnerable plastic, and are very easily scratched or - even worse - scuffed, which is thousands to tiny scratches at once. The mirrors in HDready sets are front surface or mylar - you are not cleaning glass at any point, with these sets.
As such you need to be painfully careful, as damage is immediate and permanent. I recommend contacting me directly before doing any optics cleaning on any projection set, esp. CRT RPTVs.
But oh, what a difference a day makes! This can all be done in a day, after which your CRT RPTV will look like a new TV again!
Mr Bob510-278-4247bob@imageperfection.com
As such them 4_26_2012_8_26_17_pm.jpg4_26_2012_8_26_33_pm.jpg

Jan 14, 2012 | Pioneer PRO-710HD 64" Rear Projection...

1 Answer

Our rca hdtv monitor will work for approximately 15 mins before turning itself off then on and off again two more times. also the left side of the screen is starting to show a little more blue than usual....


pidksmith,

If you see something leaking from the blue tube it is probably coolant. You will need to find the leak and repair it and fill it with the proper amount and type of coolant. Projection TVs with CRTs have to have coolant covering the face of the CRT or they will overheat. Sometimes they can develope a leak. You will need to unplug the unit and remove the rear lower cover. Looking at the blue CRT from the top you should see 4 screws holding the lense on to the crt. Do not remove any other screws or you will change the mechanical focus. Remove the lense and look for the leak. If it can be fixed use good epoxy to seal it. Order a bottle of CRT coolant from http://www.mcmelectronics.com . There should be a filling port on the top of the crt. Fill the chamber to the required level, close, reassemble and you should be back in buisness. If the leak cannot be fixed you would have to replace the crt. I have a tip for that at http://www.fixya.com/support/r4573850-change_crt_in_projection_tv which explains how to do this.

Thanks for using FixYa and for the great rating.

hardrocko

Mar 21, 2011 | RCA D52W20 52" Rear Projection HDTV-Ready...

1 Answer

Lost focus.looks 3d. red double. cant focus on red convergence.


This is a very common failure on Projection TV2_bing.gif sets.


  • 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.
Here are some photos of convergence problems.1d5e2cf.jpg


ff5b9f6.jpg
7deade1.jpg

Here is a quick test....

Using your original remote go-to the settings menu then goto the convergence section.

Try to adjust the red and then the blue convergence.

You should be able to move RED and BLUE in all directions - up, down, left, and right.

If you can't move them in all directions your convergence chips are bad and should be replaced. This is a common problem.

Note: If you TV has as flash focus or magic focus button only try pressing the button. If it fails to fix the convergence your need to fix it. See below for a solution

47a7bc4.pngSOLUTION

You will need to replace the convergence chips and possibly some convergence resistors and pico fuses.

This is a a fairly easy DIY job if you know what you are doing or you can call in a pro.

If you want to do the repair yourself check the site www.TvRepairKits.com.

Their kits include a step by step instruction guide, original OEM Sanyo STK chips, convergence resistors, pico fuses, thermal paste, email/phone support, etc.

Problem #2 CRT Fluid is Cloudy

Projection 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 video.

Pic of a set that needs the fluid changed. Notice how dull the colors are and how white the screen looks. The screen may also look red, orange, dull, etc.

7c190d8.jpg

TV set after fluid change. Notice how bright the colors are now. Everthing looks crisp and sharp again.

a798d23.jpg



724bcba.pngSolution #2


What you will need to do is replace the coolant and clean the crt. You can get a repair kit from www.TvRepairKits.com that includes replacement coolant,step by step instructions, etc.

Jan 28, 2010 | Philips Magnavox 51MP392H Rear Projection...

1 Answer

Focus dial shorting to the chassis.


My friend it seems like it's about time for this set to retire there is a high voltage in a low-voltage flyback or line output transformer even if the TV is off and unplugged they can kill you if you have a voltage leak and you really want to keep this TV I would take it to a professional television repair shop they will have all the tools necessary to diagnose properly so please be careful when inside a CRT television good luck in your effort to repair the set

Jul 28, 2009 | Projection Televisions

1 Answer

Blue CRT issues?


Yes the puddle is related to the Blue CRT coolant leaking. You are most likely going to need a new Blue CRT drive circuit board and quite possibly a new Blue CRT if the CRT got too hot from not haveing a sufficent supply of coolant. You can get replacement CRT drives and CRts at the following link.
http://servicemanuals.vstore.ca/

Jan 15, 2009 | Samsung HCL4715W 47" Rear Projection...

1 Answer

Philip RPTV


There are a few malfunctions that can cause such.

ONE: Mirrors out of location. But it usually throws the picture off center, also. This can be caused if the set is dropped or kicked badly.

TWO: Out of focus. Can be caused by drift of the circuits or from a malfunction of the video drivers. You can check this by going to the crosshairs and see if the lines are sharp and narrow. If not, then the focus is off badly - most likely the blue gun. You may be able to set the focus and other levels for brightness and contrast and color to optimize this weakness as these are all somewhat interrelated, especially in the extreme settings. You can make adjustments for these above what is available from the OSD by getting into the service mode. See this web site for instructions on how to enter it. http://www.fixyourowntv.com/servicemenu.php

THREE: Worst case is the blue gun or projection tube is failing and needs replaced - which I don't recommend due to the very high cost of doing so.

FOUR: And it is possible the blue gun/tube has been knocked out of alignment by dropping or moving the set.

I favor the focus adjustment as the first remedy to try. You can do that yourself. But if it turns out the mirror is out of location or the blue gun is defective you will need a technician for help on those items.

Nov 13, 2008 | Projection Televisions

1 Answer

Philips magnavox 9p6040 projection tv


no the coolant needs to filled all the way, you did right. try focusing the blue tube with the blue focus control, and you may have to run a multi point convergence adjustment through the picture settings menu.

Jun 20, 2008 | Philips 9P5534C 55" Rear Projection...

2 Answers

Tv w/ "loose magnifier"


If the lens came loose the CRT would leak its coolant all over the chassis. Sounds as if the Blue CRT may have a short and thats why its not working. If thats the case your looking at about 300.00 for a replacement tube if you install it about 600 if a shop does it.

May 21, 2008 | Sony KP-65WV700 65" Rear Projection HDTV

3 Answers

Red lines and shadows, convergence wont work


Your TV most likely has one or more possible problems.

Problem #1: Convergence Chip Failure ( common problem )

Here are some of the most common symptoms and example photos of a convergence problem
  • 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.
701cb04.jpg
77ea520.jpg
f0900cb.jpg
Here is a quick test....

Using your original remote go-to the tv settings then goto the convergence section.

Try to adjust the red and then the blue convergence.



You should be able to move them up, down, left, and right.

If you can't move them in all directions your convergence chips are bad and should be replaced. This is a common problem.

2c07611.pngSolution #1

You need to replace the convergence chips and convergence resistors. Check the site www.TvRepairKits.com. They have put together a kits for most models. If you don't see a kit for your set send them a quick note and they will put one together for you. Their kits include a photo instruction guide, original OEM Sanyo STK chips, convergence resistors, pico fuses, etc.


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

2c07611.pngSolution #2


What you will need to do is replace the coolant and clean the crt. You can get a repair kit from www.TvRepairKits.com that includes replacement coolant, photos. instructions, etc.

Feb 02, 2008 | JVC AV-48WP30 48" Rear Projection...

2 Answers

Kp-57ws500


Do either the red or the green crts come up at all?? If not the heaters in the blue crt could be bad - loading down the HV and the shutdown circuit turns the set off.. Only repair for that is to replace the blue crt, but I would have it tested first.. In the shop here we use a B&K467 to test for shorts and emission leaks but that's old school.. B&K has since come out with far superior crt tester/rejuvenators..
Bill

Dec 09, 2007 | Sony KP-57WS500 57" Rear Projection...

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