samsung 27" blanks out

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  #1  
Old 10-31-02, 08:28 AM
NormyJr
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samsung 27" blanks out

samsung TC2750S
mfg June 1991
SN 3AAA600
The TV blanks out on me more and more.
When it blanks out the power LED goes out.
It sounds like the High Voltage turns off.
There is a faint blue line across the center of the tube. Sound goes off too. After a while it will usually come back on.
I replaced the HVPS a few years ago because it was arcing. I resoldered it, checked for obvious solder joints, did a static tests of diodes,resistors and caps. It sounds like it is going into shutdown mode. Can you give me any hints on components to look at and circuits, also a place to find a schematic? Thanks, NormyJr
 
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  #2  
Old 11-03-02, 03:12 PM
FREDDYG_001
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RreTech Tip as follows:


1) Dead with squeal from smps./Bad solder joint on pin#9 of the smps transformer.

2)Power-Acts like shutdown./Relay(RI-801) unlatching when hot.

3)Dead-Was intermittent./Solder bad at Tp800 smps transformer and other joints in area.

4)Dead-Relay clicks./Check Dp406 in horizontal driver circuit. 12volt supply at the cathode would drop to zero upon power up.

5)Dead-Relay clicks only./ Qp802 (Ksc2328a).

6)Dead./Resolder all pins of switch-mode transformer (smps).



Fred

 
  #3  
Old 11-05-02, 07:02 AM
NormyJr
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I think I found it...

Thanks for the tips Freddy, I think I found the cause of the shutdown. By tapping on caps I found it would shutdown when I tapped on CA28 (2200mf). I replaced it and so far, so good. Now the not so good news....The TV is hooked to cable and some of the channels come in really poor quality (particularly the lower channels 2-8), most are very good. By poor quality I mean some have horizontal lines of distortion, some are fuzzy. Wish I could explain it better. This is definately a different problem from the shutdown problem as it was doing this before the shutdown problem started. Also there is a vertical line about 1.5" from the left side of the tube that looks like noise. This vertical line is present on all channels. Any ideas on this one? Thanks ! Hey at least I have TV now!
 
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