GND 0
GND 0
STB 2.8
5V S 4.84
5V S 4.84
12V slow drop to 0.01
12V slow drop to 0.01
GND 0
BR1 slow drop to 0.01
SW slow drop to 0.01
GND 0
GND 0
5V_M slow drop to 0.01
5V_M slow drop to 0.01
The 12v starts out around 7.9 and then drops. The 5v_m starts out around 4.8 and drops
This is the first time it's been powered on in days and this time plugging it in with the resistors in there were a lot of speaker pops which at the same time resulted in the readings for the dropping voltages to spike up and fall with each pop.
I wasn't able to reproduce this effect.
So I've applied heat with a blowdryer to the area you pointed out. I tried pinpointing the flow to the different electrolyte caps in that area 4 or 5 times and got nothing. Then I decided to just hit the whole area circled and now I'm getting the spiking voltages.
Is it one of the blue capacitors or is it one of those short grey tower looking things?
I still can't pinpoint where the bad component is. Could it be a transistor?
I've been messing around with plugging/unplugging the set and taking readings. The last time I checked I was getting a clicking sound from the PS board and it's like I had heated up the main board.
There's a big resistor on the PS board that has over 15V on one side but 0V on the other. What's the wattage on that resistor?
Do you have anything to check capacitance with? May be worth a try looking at that big blue cap C842. Resistors you can check with the power supply disconnected and your DMM in Ohm mode. If any thing gives you something weird, it is always wise to lift a leg or take the component out of circuit and check it with the DMM.
And we still need to see how much DC voltage is on the big black filter cap.
Ok I unscrewed the PS board and propped it up with a book so I could get to those terminals. That big cap reads 416-417VDC.
What else should I be checking? I don't have a place where I can have this tv laid out and opened so everytime I get done checking something for you guys it wont be until the next day that I can get back to it.
I checked the resistors on the PS board and the big 1k resistor in the lower right corner is bad for sure.
Does anyone know the wattage on that one? 5w? 10w?
"That big cap reads 416-417VDC." Are you using new meter? That reading is on the high side.
I know that resistor is bad because it read out to 0.02 when set to read 1k ohms.
My meter is fine because I gave it to one of our electricians to re-calibrate and I verified VDC and VAC were matching what his read.
I did graduate from ITT Technical Institute with an Associates degree in Electronic Engineering so I do know how to use a DMM. However I did graduate back in 2002 so my knowledge is a little old and I don't remember a lot of it.
"I know that resistor is bad because it read out to 0.02 when set to read 1k ohms." You should read that resistance again with one leg of the resistor off the board, in my 40 Years I never seen MOX resistor goes shorted circuit. From 1000 Ohms to 0.02 Ohms?
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