SONY KDL-32NL140 no power light

[budm]

Re: SONY KDL-32NL140 no power light

The readings look bad, especially this one:
Diode mode
Pin 1 =
Pin 2 = Black or Red
Pin 3 = Red or Black
Pin 4 =

reading = 0.l

That would have caused the main ac fuse to blow since pin 2 and 3 are the AC input pins.
Please pull the bridge off the board and test it again.

This one is also wrong:
Pin 1 = Black
Pin 2 =
Pin 3 =
Pin 4 = Red

reading = .478

[zogthegreat]

Re: SONY KDL-32NL140 no power light

OK, after trying to desolder without desoldering wick , I finally got it off.

Here are my results, I tested in diode mode on my tester:



Red lead to pin:

Pin 1 = .0L
Pin 2 = .0L
Pin 3 = .0L
Pin 4 = .924

Black lead to pin:

Pin 1 = .923
Pin 2 = .0L
Pin 3 = .0L
Pin 4 = .0L

[budm]

Re: SONY KDL-32NL140 no power light

OK, after trying to desolder without desoldering wick , I finally got it off.

Here are my results, I tested in diode mode on my tester:



Red lead to pin:

Pin 1 = .0L
Pin 2 = .0L
Pin 3 = .0L
Pin 4 = .924

Black lead to pin:

Pin 1 = .923
Pin 2 = .0L
Pin 3 = .0L
Pin 4 = .0L

I do not understand your readings, it has 4 diodes inside so what you are reporting does not make sense to me.

[zogthegreat]

Re: SONY KDL-32NL140 no power light



Sorry, does this make more sense?

Pin 1 = .0L - Red to pin 1 - Black to pin 4
Pin 2 = .0L - Red to pin 2 - Black to pin 3
Pin 3 = .0L - Red to pin 3 - Black to pin 2
Pin 4 = .924 - Red to pin 4 - Black to pin 1

The only time I got any reading was when I touch the black lead to pin 4 and the red lead to pin 1. Reversing the leads, (Red to pin 1 - Black to pin 4), I get nothing.

[budm]

Re: SONY KDL-32NL140 no power light

As shown in my diagram, you can see 4 diodes so you should be able to measure each diode inside the bridge.
I.E. diode mode
Testing diode D2: Blk on 1, Red on 2 = 0.6
Testing diode D1: Blk on 1, Red on 3 = 0.6
Testing diode D4: Blk on 2, Red on 4 = 0.6
Testing diode D3: Blk on 3, Red on 4 = 0.6

[zogthegreat]

Re: SONY KDL-32NL140 no power light

Hers what I get:

Testing diode D2: Blk on 1, Red on 2 = 0.502
Testing diode D1: Blk on 1, Red on 3 = 0.503
Testing diode D4: Blk on 2, Red on 4 = 0.500
Testing diode D3: Blk on 3, Red on 4 = 0.497

[budm]

Re: SONY KDL-32NL140 no power light

They are good. Now measure the two inner pads (pin 2 and pin 3) on the board (diode is still off the board) to see if it still show 0.1

[zogthegreat]

Re: SONY KDL-32NL140 no power light

I get .0L off the two inner pins on the board, no matter which way I put the probes.

[budm]

Re: SONY KDL-32NL140 no power light

Well, I do not know how you get this reading before then:
Diode mode
Pin 1 =
Pin 2 = Black or Red
Pin 3 = Red or Black
Pin 4 =

reading = 0.l
Put the bridge back in place and then measure the DCV between the two legs of the main filter cap again. It should show 160~170VDC.

[zogthegreat]

Re: SONY KDL-32NL140 no power light

When I measure between the filter, (red arrows), I'm still getting 0.25vdc

[/QUOTE]

Well, I do not know how you get this reading before then:
Diode mode
Pin 1 =
Pin 2 = Black or Red
Pin 3 = Red or Black
Pin 4 =

reading = 0.l

I not sure either. I'm trying to be as methodological as possible in my measurement. I have test my meter against several batteries and my coach's 12vdc and 120vac systems and it seems to be accurate.

[budm]

Re: SONY KDL-32NL140 no power light

There are two diodes that you need to check (I doubt that both of them are bad but check them any way).
Then check the resistance between:
A & B =
A & C =
D & F =
E & F =
G & H =

Something is not testing right.

[freakaftr8]

Re: SONY KDL-32NL140 no power light

I wonder if that diode could be open inline with the one side going to the main filter. I can't read the number but it's definitely a three-digit its right above the filter cap on the right side

Lol Budm you beat me to it!

[budm]

Re: SONY KDL-32NL140 no power light

There are two of them so both of them (one of them is fed through the PFC Inductor) will have to be bad.

[zogthegreat]

Re: SONY KDL-32NL140 no power light

There are two diodes that you need to check (I doubt that both of them are bad but check them any way).
Then check the resistance between:
A & B =
A & C =
D & F =
E & F =
G & H =

Something is not testing right.

Sorry, but I'm not understanding, which two diodes do I need to check? Is the two marked with the red arrows?

Do I check the resistance between the other ones with or with out power?

Thanks!

[freakaftr8]

Re: SONY KDL-32NL140 no power light

The ones he has marked as diodes and red letters B to D and C to E. Test these in diode mode on your meter. You should read almost infinite or O.L. on one side and have a reading on the other

[budm]

Re: SONY KDL-32NL140 no power light

'Do I check the resistance between the other ones with or with out power?;' I am surprised that you ask if the power is needed to be applied or not when making the resistance measurement. Did you do the diode test with power applied too?
And those resistance testing between the points are needed to find out if you do have connections all the way to the filter cap. At this point it looks to be measurement errors to me.

This may explain why you get these readings on post 20:

Pin 1 =
Pin 2 = Black or Red
Pin 3 = Red or Black
Pin 4 =

reading = 0.l

[zogthegreat]

Re: SONY KDL-32NL140 no power light

'Do I check the resistance between the other ones with or with out power?;' I am surprised that you ask if the power is needed to be applied or not when making the resistance measurement. Did you do the diode test with power applied too?
And those resistance testing between the points are needed to find out if you do have connections all the way to the filter cap. At this point it looks to be measurement errors to me.

This may explain why you get these readings on post 20:

Pin 1 =
Pin 2 = Black or Red
Pin 3 = Red or Black
Pin 4 =

reading = 0.l

Hi budm,

No, there was no AC power when I did the diode test.

Here are the results from my latest test:

A & B = 00.9
A & C = 00.9
D & F = 00.9
E & F = 00.9
G & H = 00.9

I used the resistance setting on my meter to do the test, no AC power.

Just to clarify, I am a total noob to this. Although my son has a degree in Electronic Technology, and a BA in Computer Engineering, my talents lie elsewhere. Whereas changing a bad cap or two to fix a monitor is relatively simple, this is much more advance for me and I am trying to learn to the best of my abilities. Hence me asking what the best way to perform the test. I just wanted you to know what my level of "expertise" in this area is, i.e. minimal at best. That's why I try to do as many test as possible so that you guys here on the forum will have as much data as possible to work with.

[budm]

Re: SONY KDL-32NL140 no power light

Hi budm,

No, there was no AC power when I did the diode test.

Here are the results from my latest test:

A & B = 00.9
A & C = 00.9
D & F = 00.9
E & F = 00.9
G & H = 00.9

I used the resistance setting on my meter to do the test, no AC power.

Just to clarify, I am a total noob to this. Although my son has a degree in Electronic Technology, and a BA in Computer Engineering, my talents lie elsewhere. Whereas changing a bad cap or two to fix a monitor is relatively simple, this is much more advance for me and I am trying to learn to the best of my abilities. Hence me asking what the best way to perform the test. I just wanted you to know what my level of "expertise" in this area is, i.e. minimal at best. That's why I try to do as many test as possible so that you guys here on the forum will have as much data as possible to work with.

OK, so you do have continuities on those connections, then you need to test those two diodes in the red circles I have marked.

[zogthegreat]

Re: SONY KDL-32NL140 no power light

you need to test those two diodes in the red circles I have marked.

Opps! Sorry, I forgot to give you that info. I get .391 off of both of them. Diode mode, no power.

[budm]

Re: SONY KDL-32NL140 no power light

Opps! Sorry, I forgot to give you that info. I get .391 off of both of them. Diode mode, no power.

Well, the whole thing does not make any sense right now since you do have 120VAC feeding the two AC input pins of the bridge rectifier, and you do have two good diodes and good connections all the way to the main filter cap but yet you do not get any DCV on the main cap.