troubleshooting a tv power supply

loosewire

Joined Apr 25, 2008
1,686
This photo trouble shooting with red lines
will grow Into other things,this Is a first
with excellent photo's and Indicators
good job guys.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
soldered in the one cap.
ok. ic has 12 DCV at pin 2.
pin1=0
pin3=0
pin4=0

other side starting from bottom
pin5=0
pin6=0
pin7=0
pin8=0

probably not good right?

with continuity test of analog meter. cap beeps both ways. i'll take my meter into sears around 3 o clock. don't think they are going to replace a $200 Fluke DMM without a reciept. Mom lost it. Was birthday gift. Not even 3 months old. :(

DSP? you used that before. what is that? digital signal processing?
 
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R!f@@

Joined Apr 2, 2009
10,004
soldered in the one cap.
ok. ic has 12 DCV at pin 2.
pin1=0
pin3=0
pin4=0

other side starting from bottom
pin5=0
pin6=0
pin7=0
pin8=0

probably not good right?
This is bad thing and a good thing



DSP? you used that before. what is that? digital signal processing?
Yup... just a short version, for all the analog and digital signal processors
 

R!f@@

Joined Apr 2, 2009
10,004
Bad thing is that it's a SMD we are dealing with. ( not to me but to you, the more fault I see the happier I get, so it's always a good thing to me)

Good thing is we have found a fault.
Now the problem is to measure the resistance from the pin 3 of that IC to ground.
Give me the exact DC resistance you get, power should be off, caps discharged, Keep the meter connected for a while to see if it changes, I need you to have the probes touching the IC lead for atleast more than 5 sec.
 

Thread Starter

johndoe45

Joined Jan 30, 2010
364
at pin 3 to the rectangle box you told me to ground to if that is what you were talking about when you said ground.

at x100 ohms. it is at like 22 mark
 

R!f@@

Joined Apr 2, 2009
10,004
OK time to solder the inductor and cap.
see the PIC.
I inductor track seems damaged, so you need to make sure the IC pin3 has a connection to the inductor..
Remember what you did with the fuse. Just like that.
After soldering use the meter and check pin 3 and inductor has 0Ω.

Time for voltage measurement. I am editing another pic for that.
 

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R!f@@

Joined Apr 2, 2009
10,004
Power up the TV and measure the DC voltage as in the PIC
Before giving power check the resistance between the collector and pin 7 as shown in the pic
 

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