identity tv part

[budm]

Re: identity tv part

So the resistance reading between GND pin and the 5VSB pin is showing less than 1 OHM?

[nosugartonight]

Re: identity tv part

There is no short between cn201 and 5vsb. What I was doing is, in ohms' mode. Black lead to frame ground and touching red lead to legs of components " resistors, misfits ,capacitors, transforms cold side " shows grounded. That is not good right?!

[budm]

Re: identity tv part

There is no short between cn201 and 5vsb. What I was doing is, in ohms' mode. Black lead to frame ground and touching red lead to legs of components " resistors, misfits ,capacitors, transforms cold side " shows grounded. That is not good right?!

What do you mean 'shows grounded'? as I indicated, what is the resistance reading? The power supply outputs have loads connected between GND and the supply pins.
I.E if the 5VSB pin has 1000 Ohms resistor connected between GND and the 5VSB pin, then you will see 1000 Ohms after the filter caps are charged up by the meter. So does it means that it is bad? No.

[budm]

Re: identity tv part

Ok here what I have discovered. Before I removed the power board to take pics. There was no voltages on any pins . Everything on hot side shows voltages. I believe there all right. No voltages on cold side. But when I went to put the board back. I only used a couple of screw's. I rechecked the pins. To my surprise there are voltages on the pins. When I put the bottom right screw in. Lost all voltages on pins. Tracing from the 5v pins . Everything shows grounded. All the way up to pc702 which looks like a IC but only has 4 legs. . I will post a pic. I hope you understand what I'm saying

So what are the Voltages on the pins you are getting? 5VDC at the 5VSB pin?
The more details you give us the more help you will get in troubleshooting the problem.
Also when you use the chassis GND as the GND ref for your meter, if the Ground pads (where the board mounting holes are) are not properly mounted then you will not get the Voltage readings; the Cold side circuit GND is connected to the mounting holes of the board to make connections to the chassis.

[nosugartonight]

Re: identity tv part

Here is a pic so you can see what I have my meter set at. This is the voltages I get on pins . All 5vsb pins. All 12v pins,and the two 24v pins. If I put all the screw's in to hold the board. I lose voltages on all pins.

[budm]

Re: identity tv part

That is only 0.315V! So you are not really getting 5V as it should. To get proper Data at this point, you should use the GND pin of the connector for your meter.
So, whet is the resistance reading between GND pin of the connector and the 5VSB pin? We still need that data.
We need to get 5VSB power supply working FIRST.
Did you check the resistors that RJ suggested?

[nosugartonight]

Re: identity tv part

I'm not sure about checking resistance. That is checked in ohms,right? If so the meter does not stay constant. The reading keeps changing. Do you go by the first numbers shown. In mean time I will research how to check resistance. Thank you for your help ��

[budm]

Re: identity tv part

Set meter to Ohm mode (read your meter owner manual). Touch the two probes of the meter together, it should show < 1 Ohm, then use the meter to probe the resistor R901, R902 as RJ suggested.
You MUS NOT have TV plugged into the AC outlet when testing resistance.
Make sure to report EXACTLY as to what is shown on the meter display.
BTW, you have proper tools to do good soldering works especially the SMD device, right?

[nosugartonight]

Re: identity tv part

Yes proper tools. Will report back asap. Thank you ��

[nosugartonight]

Re: identity tv part

In ohms mode with leads together read's all 0's
R901 read's O.L R902 read's 1.2

[R_J]

Re: identity tv part

dc voltage from the main Capacitor C800 is feed through R901, through the transformer T901 and to Q901. I suspect Q901 is shorted, R901 acts like a fuse for the switching circuit

[nosugartonight]

Re: identity tv part

I think q901 is ok,out of circuit reads .492. That is acceptable correct?

[nosugartonight]

Re: identity tv part

.492

[nosugartonight]

Re: identity tv part

After resoldier Q901 reads .501 both measurements were in diode mode

[budm]

Re: identity tv part

Read the RESISTANCE between the Source pad and the Drain pad where the removed MOSFET legs were soldered to. Do the same resistance between the Source and the Drain of the removed MOSFET also.

[R_J]

Re: identity tv part

Check the parts around Q901 like zd901, d901, c901. also does R901 look like it is blown apart or does it just measure open? If the mosfet and other parts around it are ok, it is possible the resistor just went open, not likely but possible.

[nosugartonight]

Re: identity tv part

Resistance between source and drain 10.02. I will take it back out to give you those measurements R901 looks ok. Actually I have looked the board over really close,front and back and see no burned,blown components. I will recheck all the above.

[budm]

Re: identity tv part

"R901 read's O.L" It is blown open circuit!
"Resistance between source and drain 10.02." Ohms? K Ohms? M Ohms?
You still need to do this on those two solder pads on the board: my request "Read the RESISTANCE between the Source pad and the Drain pad where the removed MOSFET legs were soldered to."

[nosugartonight]

Re: identity tv part

Will do. And post measurements. Again I want to thank you for your help. Continue tomorrow ��

[nosugartonight]

Re: identity tv part

R901 is blown rechecked after taking out of circuit. Q901 I believe is shorted now. After I took it back out,it reads OL from source to emitter and 13.30ohms source to drain. This is a PNP? If so I believe I'm checking it right. It was reading.492k in diode mode. Now in diode mode only reads .501k on drain, O.L on emitter. The resistance between pads source to drain 10.56ohms. Think I over heated Q901 or maybe static electricity from me. So what's next.