RCA Model P46729BA Distorted Picture


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RCA Model P46729BA Distorted Picture

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jagged
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Aug 12, 2011, 6:12 PM

Post #1 of 19 (5904 views)
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RCA Model P46729BA Distorted Picture	Can't Post

I have an older RCA rear projection tv model #P46729BA, chassis #PTK169PCA. The picture gets distorted and rolls vertically every once in awhile. Is there any way to adjust this? I can adjust the convergence, but this still doesn't clear up the distortion. It seems to be worse when you first turn the set on. I have a few screen shots so you get a better idea of the problem, but can't see anyway to upload to the forum.

Thanx!

Ron.M
Veteran

Aug 12, 2011, 6:34 PM

Post #2 of 19 (5900 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;....

Quote

I have a few screen shots so you get a better idea of the problem, but can't see anyway to upload to the forum.

Try to "copy & paste" them..If that doesn't work , paste a link to them...
For example , upload the pix to photobucket or imageshack or ??? & they have links there you can post here for us to go & see...
IF you copy & paste the pix , use the "Preview Post" feature to check on their size...
That will show you what they will look like before you post them in your thread...
PLEASE do not post pix that we need an "IMAX" monitor to view them on... Unsure

...
If too large , go back & adjust them accordingly...THANKS....

GOOD LUCK.... Sly

.....

Later..Ron.M...... Cool

....
Veteran & Retired TV technician

jagged
New User

Aug 13, 2011, 2:31 AM

Post #3 of 19 (5891 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Here's the link. hope it helps. Copy and paste don't work.

http://s299.photobucket.com/...lariss_05/TV%20pics/

Ron.M
Veteran

Aug 13, 2011, 5:06 PM

Post #4 of 19 (5883 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;...

Thanks for the link....

Quote

Is there any way to adjust this?

NO , you have parts going/are bad...
You apparently have a bad cap(s) in the power supply...
We can go at this in 2 different ways...

But 1st;...

Questions;...

How much electronic/TV repair background experience do you have ???? ..(PLEASE be honest ...)

Does the problem slowly go away the longer the TV is on ????
In other words , does the pix get better as the set is on longer & gets warmer ???

Does it totally go away ???

You will need a DVM and an ESR Meter (BEST) & a can of electronic freeze spray ..(Just about as effective)...
Do you have any or part of this ^^???
IF needed can you get any or part of this ^^ ???

I will need answers to ALL the above....

Have a GREAT day.... Smile

....

THANKS.... Sly

....

Later...Ron.M..... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Aug 13, 2011, 5:07 PM)

jagged
New User

Aug 13, 2011, 9:46 PM

Post #5 of 19 (5875 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Thanx for your help! I have a small amount of experience in electronics. Some soldering of capacitors eprom chips and diodes in circuit boards. I do have a digital volt meter, but I don't have an equivilent series resistance meter. I can probably do a search for one and I should be able to get the can of freeze. The pic does improve the longer the set is on, but never totally goes away. The tv is here at my cottage and it only gets used 2 months every summer.It would be worth a try to fix it, the worst that could happen is I might have to get up early on a Saturday morning, because the dump is only open on Saturdays and it closes at noon*S*.

Ron.M
Veteran

Aug 14, 2011, 12:14 AM

Post #6 of 19 (5853 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;.....

THANKS for your honesty...

An ESR Meter would be a BIG help....
They aren't that expensive to buy , but if you are going to use it for this set only , it would be better if you could borrow one from a friend...
Possible ????
If not , we'll go to plan "B".... Wink

...

You will have to pull part way out & flip the "PTK169PCA" (May be called CTC169"xx" in the set) board over to work on it...
There is some wiring you will have to disconnect , pull the board out , reconnect the wiring to run some tests , then flip it over....
That said....

Lets try this;..
For starters:...
(The board STAYS IN the set)....
The "169" board is on the left side of the chassis (Assuming you have removed the back cover)...
On the rear right side with a red wire coming from the top is a transformer...(that's called the "Flyback & WILL have ~30,000 volts on that red wire when the set is on & can hold that charge for a VERRRY long time even after the set is off & unplugged)
Right in front of the Flyback about the middle of the board is another smaller transformer...
A boxy looking thing...
That is the power supply transformer called "T4102"....
Around that transformer are various sized lytic caps....
For now , if you so choose , (With the TV OFF & UNPLUGGED) take a peek at the top side of that area & see if any of those caps have a swelling or a bulged top...
See if the labels on the caps are not shrunk up or split..
Especially at the top of the caps...
Do nothing else...
IF you did check the area , please post back with what you saw...
If not , let me know anyway how you feel about proceeding...
The problem you have is not a serious problem as far as cost goes , but can be a problem finding the bad parts....
It will take time & patience...
You still up for it ????

THANKS.... Sly

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Aug 14, 2011, 12:20 AM)

jagged
New User

Aug 14, 2011, 5:32 AM

Post #7 of 19 (5847 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Sounds ok to me. I've been looking at the back, and i can see how to remove the pressboard cover, the plastic cover that bulges out the back, needs a few tips. I know all about high voltages, and won't touch anything without proper instructions first. You never know, I might be able to find that meter on ebay for a cheap buck. I'm actually a retired cnc machinist, so if you ever need help on that end, I'd be happy to help.
Thanx again!

Ron.M
Veteran

Aug 14, 2011, 4:35 PM

Post #8 of 19 (5839 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;.....

Leave the plastic cover on...
That piece also holds the glass mirror assembly that you do not want to break...
IF there's a lot of missing screws , it would be a good idea to replace the missing ones...
There is some weight to that unit...

Quote

I might be able to find that meter on ebay for a cheap buck.

IF you do , 2 things...
1) Make SURE it's a working unit & please check with me before you bid...
2) Make sure the seller gives a warranty , has a high rating & is in the USA...

Looks like we both are retarded , oooops , retired...
What is a cnc machinist ???

Back to business;=>...
When you complete this , please post results...

Quote

Lets try this;..
For starters:...
(The board STAYS IN the set)....
The "169" board is on the left side of the chassis (Assuming you have removed the back cover)...
On the rear right side with a red wire coming from the top is a transformer...(that's called the "Flyback & WILL have ~30,000 volts on that red wire when the set is on & can hold that charge for a VERRRY long time even after the set is off & unplugged)
Right in front of the Flyback about the middle of the board is another smaller transformer...
A boxy looking thing...
That is the power supply transformer called "T4102"....
Around that transformer are various sized lytic caps....
For now , if you so choose , (With the TV OFF & UNPLUGGED) take a peek at the top side of that area & see if any of those caps have a swelling or a bulged top...
See if the labels on the caps are not shrunk up or split..
Especially at the top of the caps...
Do nothing else...
IF you did check the area , please post back with what you saw...
If not , let me know anyway how you feel about proceeding...
The problem you have is not a serious problem as far as cost goes , but can be a problem finding the bad parts....

Have a GREAT day.... Sly

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

jagged
New User

Aug 15, 2011, 9:27 PM

Post #9 of 19 (5829 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Hi Ron, thanx for the detailed reply. A CNC Machinist is a specialist that programs sets up and operates computer numerical controlled machine tools. As a Machinst Journeyman, that's what I have been doing for the last 31 years.
I took the set apart and I really couldn't see anything out of the ordinary. I took a bunch of pics, so maybe your trained eye can see something I can't. Once again, thanx for your help!
http://s299.photobucket.com/...lariss_05/TV%20pics/

Ron.M
Veteran

Aug 16, 2011, 12:26 AM

Post #10 of 19 (5819 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;...

With the exception of pix #4 (Too dark..) , ALL the rest are EXCELLENT pix....
THANK you........

Quote

I took the set apart and I really couldn't see anything out of the ordinary.

Neither could I ....
But , not always can a pix show you what you need to see...

On to plan "B"...
BTW...
NO plan "C" ...
I suggest you get a can (12 or 16 oz size) of electronic circuit freeze...
Get the type that has a trigger pull & NOT the center press button type...
Will explain later....
Shouldn't cost more than $6 ~ $8.00 USD....

While we're waiting on that....
In your pix below;....
Immediately in front right side of the flyback next to a large black cased lytic cap is a diode...
On the board near it should be marked CR4116....
Get out your handy dandy meter , set it to read ~140 volts + DC ..
Hook up your negative lead to the tuner coax fitting or the tuner case...
Use care if you use the tuner case so that you do not stick the meter lead thru the holes in the
tuner case & short out something inside the tuner...
Hook up the positive lead to the band end of that diode...
Keep ALL leads AWAY from the sides & top etc of the flyback...
Voltage DOES seep thru the insulation of the flyback..
Your meter can be damaged....So use care..
Turn on the TV & read volts...
Turn off TV , disconnect meter leads...
Post reading...

BTW;...
I can not cut down on the size of your pix with this limp-along dependable old computer...
When my good one is working again I will try to make it smaller....
Sorry it's so big.... Unsure

....

I would like to see some REALLY GREAT pix of the set's problem from a cold start...
The ones you had up before were a bit hard to make out the pix problem....
Then leave the set on for a long time till it gets it's best & take a REALLY GREAT pix of that...
Check for pix clarity & focus before you post...THANKS... Smile

....

Have a GREAT evening.... Sly

......

Later....Ron.M.... Cool

....
Veteran & Retired TV technician

jagged
New User

Aug 16, 2011, 1:51 AM

Post #11 of 19 (5814 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Hi, I'll make the pics a little smaller next time. I was trying to get as much detail as possible. Trying to jam my wife's little Canon digital camera in there, it was hard to get the focus just right. I put the TV back together again, cause that's all we have up here in Northern Ontario, and actually the picture seems a little better. I will take the pics you want tomorrow, then test the diode and I'm sure the Radio Shack in Kapuskasing should have the spray. I just made a fresh picked rasberry pie and it should be baked in about 45 min., I'll save you a slice.
Thanx!

Ron.M
Veteran

Aug 16, 2011, 3:01 AM

Post #12 of 19 (5810 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;....

The pix size is NOT your fault....
Do NOT change the size...
It has to do with photobucket & this website.......
It happens when I copy & paste...
I will try to figure that out on my good computer...
Do not change the way you are taking the pix...
This last batch is GREAT !!!!

Quote

then test the diode

You are NOT testing the diode !!!!
You ARE reading the voltage that it is producing along with other parts....

Quote

Northern Ontario

Is that anything like North Dakota & South Dakota ????
I didn't realize you had a "South Ontario" .... Wink

....
JUuuust kidding.... Smile

.....

Quote

I just made a fresh picked rasberry pie and it should be baked in about 45 min., I'll save you a slice.

Smells good....
I'll take it !!!!

See ya tommorrow.....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

jagged
New User

Aug 16, 2011, 3:37 AM

Post #13 of 19 (5809 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

In Reply To

Quote

then test the diode

You are NOT testing the diode !!!!
You ARE reading the voltage that it is producing along with other parts....

Quote

Northern Ontario

Is that anything like North Dakota & South Dakota ????
I didn't realize you had a "South Ontario" .... Wink

....
JUuuust kidding..

Actually it isn't anything like N+S Dakota. Ontario is the largest province in Canada and mostly everything is the same, but there is a division between Northern and Southern ON, in a few ways. Because it's generally more isolated and a lot colder up here, the government has given some incentives to move here. License plate stickers are 35 bucks per year here, but 76 in the south. Property taxes are given a northern tax deduction, heating and electricity gets deductions too. Unfortunately I live in Southern ON, and just cottage here, so I get nothing, except great fishing and fresh berries to make a pie! Talk to you tomorrow, John

jagged
New User

Aug 18, 2011, 8:34 PM

Post #14 of 19 (5794 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Hi, sorry I was so long getting back, but the parts came for my outboard, so I fixed that and the weather is too nice for tv anyways. I took a series of pics of the tv as it warmed up, but never had a chance to meter the diode. Couldn't find anywhere that had the spray in our local hick town, so I guess since I've only got 10 days left up here, it will probably have to wait till next year. The tv is to big and heavy to transport, could i take the board with me and test it at home? or maybe ship it to you for a price?
http://s299.photobucket.com/...lariss_05/TV%20pics/

Ron.M
Veteran

Aug 19, 2011, 12:21 AM

Post #15 of 19 (5768 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;....

Quote

but never had a chance to meter the diode.

Try to find the time to take a reading there...
It may give me a valueable clue...

Quote

could i take the board with me and test it at home?

Impossible !!!!....NO Offense , but HOW would you test it ???...

Quote

or maybe ship it to you for a price?

Impractical.....
& I do not have a shop anymore...
I have NO way to test the repair....

Quote

The tv is to big and heavy to transport,

My main TV is nearly the exact same TV as yours...
& yes it IS heavy....

I took a look at those pix....

GREAT pix !!!!....THANK you ........

I stand on my earlier suspicion , that you have a power supply problem....
That diode reading may clinch it for us...
It'll only take you a couple of mins to do....
You won't even have to pull the chassis out..... Wink

...
Then you will need the circuit freeze to nail down the bad caps...

Let me know....

Later...Ron.M..... Cool

....
Veteran & Retired TV technician

(This post was edited by Ron.M on Aug 19, 2011, 12:23 AM)

jagged
New User

Aug 20, 2011, 7:48 PM

Post #16 of 19 (5741 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

While we're waiting on that....
In your pix below;....
Immediately in front right side of the flyback next to a large black cased lytic cap is a diode...
On the board near it should be marked CR4116....
Get out your handy dandy meter , set it to read ~140 volts + DC ..
Hook up your negative lead to the tuner coax fitting or the tuner case...
Use care if you use the tuner case so that you do not stick the meter lead thru the holes in the
tuner case & short out something inside the tuner...
Hook up the positive lead to the band end of that diode...
Keep ALL leads AWAY from the sides & top etc of the flyback...
Voltage DOES seep thru the insulation of the flyback..
Your meter can be damaged....So use care..
Turn on the TV & read volts...
Turn off TV , disconnect meter leads...
Post reading...

Hi, I get 145.5 as soon as I plug the TV back in, then it goes to 143.4 when I turn the set on.

Thanx!
John

(This post was edited by jagged on Aug 20, 2011, 7:51 PM)

Ron.M
Veteran

Aug 20, 2011, 8:09 PM

Post #17 of 19 (5735 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;...

THANK you for taking the reading..... Smile

....
However , it provided no clues...
145.5 & 143.4 are normal....
Looks like we'll need the freeze....
I don't know if we'll have enough time to nail the problem this year...
I think you have less than a week left & I can't see a way to expedite the troubleshooting process at the rate we are communicating...

Any thoughts ????

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

jagged
New User

Aug 20, 2011, 10:18 PM

Post #18 of 19 (5733 views)
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Re: [Ron.M] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

Thanx for all your help! Well there's no way I would be able to get the can of freeze up here before we leave. I'll keep in touch with the forum, and we can save it till next July. Maybe during the upcoming year, I might run across the same TV at a yard sale or something, that works perfectly and I can strip it for parts.........*S*. We can live with the pic as it is anyways, the weather has been so nice up here, we don't watch it very much anyways.
Take Care and enjoy!
John G.

Ron.M
Veteran

Aug 20, 2011, 11:03 PM

Post #19 of 19 (5731 views)
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Re: [jagged] RCA Model P46729BA Distorted Picture [In reply to]	Can't Post

jagged;.....

Yeah , I was afraid time was getting short...
Figured you were out boating anyways...
Well , let me be the first to wish you & your loved ones , a Happy Labor Day , a Very Merry Christmas (Unless that doesn't apply) , a Very Happy , Healthy , Prosperous & Safe New Year , a Happy Valentines Day , (From someone else) , a Happy Fathers Day , (Unless you don't have kids) & on & on & on ... Wink

...
Enjoy the Fall , Winter , Spring & maybe we'll see you next July...
Till then , you are MOST welcome (Sorry we ran out of time)...

Best regards.... Sly

....

Stay warm.... Smile

....

Later...Ron.M.... Cool

....
Veteran & Retired TV technician

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