[TechAssist] update2: RCA P60752EB, PTK169PEC intermittant video:goes black, has sound

  • From: Phil Bader <tjanphyl@xxxxxxxxxxxxxxx>
  • To: techassist@xxxxxxxxxxxxx
  • Date: Fri, 22 Apr 2005 09:51:51 -0400

I went back and saw the cracked corner of main board and traces  around 
location A-26. I repaired two traces but I still have this 
vertical-video flashing.
Note: I hooked up my VP301 pattern gen to  the set's composite "video 
in-1" and my pattern shows the disturbance. S-video input shows it as 
well but not quite as bad. Funny, but this set has a video output jack 
"video select out". I attached an RCA cable from that to my composite 
monitor. Picture is unaffected and good at all times from this output! 
So, wherever this jack pulls the video from the TV must be before the 
trouble. I am concentrating on vertical at this point. (help!)
Phil Bader

Phil Bader wrote:

>I pulled the chunk and benched it.Slid the main board out and 
>over,studied the bottom under high magnification. I found no cracks 
>mentioned or bad traces so far. What I did find was at the junction 
>where the yellow yoke wire solders to the board,( location terminal ID 
>"E502" ) and R523, a distinct ring crack all around both wire and 
>resistor . Had to use good light and my nerdy magnifier hood with both 
>lenses down! Tho I never actually saw a vertical collapse during the 
>effect, I bet  what I saw with the video flashing was the TV 
>safety-blanking the video as this connection arced.  Make sense? Will 
>let you know.
>Phil Bader
>
>Phil Bader wrote:
>
>  
>
>>Customer said this intermittant problem happens more now:
>>Sound stays OK.
>>I've seen it: Video intermittantly sort of streaks, then goes, leaving a 
>>black screen. Not the HV,it stays... this is definately just the 
>>composite video picture. I'm testing this on the cable tuner input now, 
>>not sure if it happens on any other inputs (just got here).
>>I'm a tech from the 1970's and this looks like the symptom where a 
>>breakdown switch is dirty and you moved it causing the video to jump 
>>out, or a video peaking coil is opening. Kind of a static lines to the 
>>right across the screen then black.Any histories on video loss like this 
>>on these? (intermittants like these are difficult to nail down)
>>Phil Bader
>>
>> 
>>
>>    
>>
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