Need guidance on SMPS repair

[BFriedl]

From thread "Need guidance on SMPS repair"

Looks to me like power supply is working fine. Low voltage supply does not
regulate all voltages. As long as they're that close, it should work. If TV
still won't power up, you've got either a bad vertical IC, and possibly some
bad caps in it's circuit, or possibly a bad dynamic focus IC on convergence
board. To check for bad focus IC, unplug the PA connector and see if it will
start. To check the vertical IC (LA7838), either replace it or check pin1
(should be 9 to 12v), pin 8 (28v), pin 13 (28v), and pin 12 (13.5-14.5v). Pin
12 is the output, and may not show much for a second or two. If the set isn't
making ANY High Voltage, the Horiz Output may have been blown by

runaway 130v.


When turned on before I started troubleshooting, I got no HV and no
sound. All I heard was a click sound of main relay turning on. First
thing to go were some inductors on the convergance board. So perhaps it
is the bad dynamic focus IC? Should I try powering this set on without
convergance board in set? Or are there some caps on the vert board that
need checking first?
TIA,
Brian

Here is a repost of March, 2002:

"I was having wiring problems in my house for"
"about 2 months and it recently tripped the"
"circuit breaker. When the power was fixed, I"
"powered up my TV (was on this same circuit)"
"some smoke started to billow out of the front"
"grille below the screen. I took off the black"
"cover and found the convergance board with some"
"fried inductors on it."
""
"Could this have been caused by my power problems,"
"slowly eating away at it with the constant sags"
"and surges?? Or did the ps go bad?"
"Brian"

--
BFriedl
A+ Certified Technician
AIM: UACybercat
** Bear Down Arizona! **
******* Go Cats! *******

 

[BWL]

Yeah, unplug the convergence board power leads; set will start up without it.
If one or more of the inductors smoked, the IC connected to them is definitely
bad. Sounds like you got one hell of a surge!