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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
Sony CRT TV flashing picture

 

 


nmags
New User

Dec 2, 2013, 12:41 AM

Post #1 of 17 (9240 views)
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Sony CRT TV flashing picture Can't Post

Hello I have a sony 29 inch trinitron tv which started to blink (picture, menu, and everything played on it) it's from 1996 and I would like to attempt to repair it by myself. Some say this problem has to be with the some of the capacitors or a cold joint solder. I would like to get some expert advice. Thanks

I think the model is KV29RS20



Ron.M
Veteran


Dec 2, 2013, 2:12 AM

Post #2 of 17 (9227 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

nmags;..

By "blinking" , do you mean going from a decent pix to a BLACK screen ???

This may be a simple adjustment....
A Sony TV this old (17 years) is due for a "G2 or Screen") adjustment...
IF you answer the folowing question , I'd be delighted to give you step by step info as to how to do it;=>....

""How much electronic/TV repair background experience do you have ????""

It's not hard to do...

When you post back , please include the model # of your TV...
Thanks...


Later...Ron.M....Cool...
Veteran & Retired TV technician


nmags
New User

Dec 2, 2013, 2:53 AM

Post #3 of 17 (9222 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

Ok I'm actually a noob in tv repair but i have some basic elctronic knowledge.

Some guy told me it could be the CRT itself and that it would have to be reactivated or something like that.

The tv model is KV29RS20

Edit: By "blinking" I mean that the image goes on and off constantly, so it's like you say a perfect image (colors, brightness, etc) and then pitch black for an instant, then perfect image again.

Also the soung never fades or mutes


(This post was edited by nmags on Dec 2, 2013, 3:13 AM)


jts1957
Veteran


Dec 2, 2013, 2:58 AM

Post #4 of 17 (9220 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

Rejuvenated. AA-2 Chassis Ron.


-------------------------
Location: Far, Far Away


Ron.M
Veteran


Dec 2, 2013, 7:43 PM

Post #5 of 17 (9198 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

  
Thanks jts1957..Smile..Smile..Smile...


nmags;....



Quote
Some guy told me it could be the CRT itself and that it would have to be reactivated or something like that.

It IS the CRT !!!..
jts1957 is right...
CRTs are never "reactivated" , they are rejuvenated when justified...
Sony CRTs as a rule , oftentimes do not fare well thru the rejuvenation process...
There are other steps that can be taken safely...

Here's what needs to be done;=>...
You'll have to remove the back cover...
On the main board is the "flyback"...
It usually sits on the rear of the board...
That is a HIGH voltage transformer that supplies the High voltage via a heavy red wire into the side of the CRT that gives you brightness..
On side of the flyback there is a small panel that will have 2 adjustments on it...
One is for "focus"...
Do NOT mess with this one !!!...
The other may be called "G2" or "screen"..
This is the one you need to adjust...
Now , this adjustment may have a small knob on it that you can turn OR have a hexagon shaped hole that looks like you'd adjust it with an "allen" wrench..
Do NOT use a "allen" wrench on this or any other adjustments in any TV..
Get a plastic adjustment tool if needed..
IF it has the knob , you should see a slot in the middle of the shaft..
You can safely use a small screwdriver to adjust this...
With the back cover off & the TV turned on with a video source , do the following;=>...
Give the TV a few minutes to fully warm up..
With the screwdriver turn the "G2" adjustment slightly clockwise till the blinking stops...
Do NOT turn it any further or you will create a problem with excess lines in the pix or the TV may shutdown..
Turn the TV off & let it cool all the way down..
(An hour or so should do it)..
Then turn it on & see how it works...
IF it still blinks , turn the "G2" a tad more till the blinking stops..
Keep in mind that IF you overadjust this control , you could cause a bigger problem..
Any glitches , post back with details..

Having fun yet...Wink..


Good Luck...Sly..

Later...Ron.M...Cool..
Veteran & Retired TV technician

(This post was edited by Ron.M on Dec 3, 2013, 1:34 AM)


jts1957
Veteran


Dec 2, 2013, 10:37 PM

Post #6 of 17 (9194 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post


Quote
Thanks jts1927...Unimpressed..Unimpressed..Unimpressed...


Who dat?


-------------------------
Location: Far, Far Away


Ron.M
Veteran


Dec 3, 2013, 1:38 AM

Post #7 of 17 (9184 views)
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Re: [jts1957] Sony CRT TV flashing picture [In reply to] Can't Post

jts1957;.....

My keyboard flipped upside down when I typed a "5" & that 2 is actually a 5 upside down...Wink...

Actually a minor "brain fart"....
It's been fixed...

Thanks...

Have a great evening & week...Sly...

Later..Ron.M...Cool..
Veteran & Retired TV technician


nmags
New User

Dec 4, 2013, 12:20 AM

Post #8 of 17 (9176 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

I'm really thankfull for the info. Actually yesterday I removed the back cover and found the "death HV"cable hahahah, gave me the creeps, but I was able to safely disscharge and observe the whole thing and locate the 2 bolts or adjustment screws so I'll be trying that flyback G2 adjustment tomorrow.

Also I am noticing that my TV is loosing focus, is there a way to repair it using that focus screw?

Tankyou very much


Ron.M
Veteran


Dec 5, 2013, 3:44 AM

Post #9 of 17 (9155 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

 
nmags;.....

Don't discharge the HV wire anymore...
Just stay away from it & you'll be OK...


Quote
observe the whole thing and locate the 2 bolts or adjustment screws so I'll be trying that flyback G2 adjustment tomorrow.

They're NOT bolts or adjustment screws !!!
They're adjustment controls...
(Variable resistors)


Quote
Also I am noticing that my TV is loosing focus, is there a way to repair it using that focus screw?

Yes , there is , but one thing at a time, OK ???



Later...Ron.M...Cool...
Veteran & Retired TV technician


nmags
New User

Dec 5, 2013, 10:50 PM

Post #10 of 17 (9141 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

All rigth ron, I managed to repair the flashing image adjusting the G2 control. (FYI in this thing those controls are metallic but everything went ok) Thank you! How should I adjust the focus control? Thanks

Edit: I'm noticing that the images are poor in blue or green color and the black looks very greenish.


(This post was edited by nmags on Dec 6, 2013, 1:16 AM)


Ron.M
Veteran


Dec 6, 2013, 1:48 AM

Post #11 of 17 (9120 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

 
nmags;....

Good , that's progress !!!...Smile...

What did the pix look like before it started blinking ???..



Later...Ron.M...Cool..
Veteran & Retired TV technician


nmags
New User

Dec 6, 2013, 2:05 AM

Post #12 of 17 (9117 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

It was actually ok, no greenish or reddish at all.


Ron.M
Veteran


Dec 6, 2013, 2:23 AM

Post #13 of 17 (9109 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

nmags;...

If you turned the "G2" up too much , that could be the reason for the discoloration...
Try backing down on the G2...
IF you get a good pix , then adjust the other control for focus...
(Either above or below "G2"..)
FYI:..These 2 controls are somewhat touchy in that it doesn't take much to get the desired results..
You just move them a TAD & you should get what you want...


Be back Fri AM...
Have a good evening...



Later...Ron.M...Cool..
Veteran & Retired TV technician

(This post was edited by Ron.M on Dec 6, 2013, 2:24 AM)


nmags
New User

Dec 6, 2013, 2:27 AM

Post #14 of 17 (9106 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

Alright Ron, i'm gonna check that setting and let you know. Thanks


nmags
New User

Dec 9, 2013, 4:04 PM

Post #15 of 17 (9072 views)
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Re: [nmags] Sony CRT TV flashing picture [In reply to] Can't Post

Ron, let me tell you everything went smooth, right now the image is crisp and the colors are vivid.

Thank you very much


danchilliwack
New User

Apr 29, 2015, 4:19 AM

Post #16 of 17 (8028 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

Ron
I just signed up to the forum to say thanks for your dec 2nd postings helping nmags with the flashing CRT problem on the Sony.
I've got a 16 or so year old sony trinitron wega 24" and over the past month it's been flashing and getting worse by the day.
Tonight I pulled it apart vacuumed out the heavier dust, blew out the lighter stuff and followed your instruction.
Betcha I only turned that screen knob 1/16 rev if that and when I looked at the screen, flashing gone.
Turned the focus knob about 1/8 rev to the right and things are looking better. And I thought I needed knew glasses...hah!
Anyway all is well for now. If it flashes again I'll give it another tad to the right.
In the end, if the tv dies, well at least I got to spend a little more time with the old fatso.
Thanks Ron
Stay sharp.
Smile


judoman
New User

Mar 20, 2020, 12:26 AM

Post #17 of 17 (4532 views)
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Re: [Ron.M] Sony CRT TV flashing picture [In reply to] Can't Post

I adjusted the “screen” nob. It stopped blinking. Working perfect for a few hours. Then it went totally black. Sound was on, but no picture.

 
 
 


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