Lg 47lh55-ua

[me2space]

Re: Lg 47lh55-ua

Thanks Marty. The connection is nice and snug, but after some testing I found the black lead to be bad. With another lead I now get 0 when I touch them together and it does not jump around at all.

I retested all 3 fuses and the all read 0. What else can I check, regulators or voltages?

[me2space]

Re: Lg 47lh55-ua

The only other thing I can think of doing before I give up is to measure some voltages on the power supply board, P200 looks promising and it even has a table for reference. It can be seen on the pic with all the wires on the right hand side of the photo.

I have not been able to locate a service manual for this model, so I'm flying a bit blind. Can anyone confirm that this is the next logical step? Anything else I should check before connecting it to power?

The only thing I know thus far is that the 3 fuses I found are fine, and that there are no bulging capacitors.

Thanks again for any advice

[selldoor]

Re: Lg 47lh55-ua

Ok - pictures are not brilliant for troubleshooting they need to be like these
Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

You are right the next step is to test the voltages on the connector- please list them with the detail off the board

Pin 1 NC
PIN2 Power on
PIN3/4 GND
and so on show the voltage shown and what your test shows.

Do the test first with the set just plugged in but not on
then do it again after you press the on button.

Then for pin 2 - power on do it again as you press the on /off button - you may need a helper.

Whilst these are low voltage take care as there are high voltages on the board - Do NOT touch heatsinks - they can be live.

[me2space]

Re: Lg 47lh55-ua

Ok - pictures are not brilliant for troubleshooting they need to be like these
Examples of what is needed

https://www.badcaps.net/forum/attach...7&d=1280167246

https://www.badcaps.net/forum/attach...6&d=1280167246

https://www.badcaps.net/forum/attach...4&d=1280167246

You are right the next step is to test the voltages on the connector- please list them with the detail off the board

Pin 1 NC
PIN2 Power on
PIN3/4 GND
and so on show the voltage shown and what your test shows.

Do the test first with the set just plugged in but not on
then do it again after you press the on button.

Then for pin 2 - power on do it again as you press the on /off button - you may need a helper.

Whilst these are low voltage take care as there are high voltages on the board - Do NOT touch heatsinks - they can be live.

I'll try to do better with the photos, although I only have a 7.1 MPixel camera and it's set to the highest resolution. Hopefully this other photo is a little better for readability.

Just to be clear for the measurements. I'm going to unplug the P201 connector in order to take the measurements. In order to measure pins 7/8 I should measure across them but to measure pin 2 I should use the grounding pins?

On a side note, I keep hearing a click when I turn the tv power on and off coming from the power supply board. It sounds like a relay but much softer than I remember them being. This is probably normal?

This information is really helpful, thanks again..

[selldoor]

Re: Lg 47lh55-ua

7MP is more than enough - good lighting is the key.

You have to have all the connectors connected to do the tests as the power supply needs to receive signals from the main board to fully switch on.
Sometimes you can get the probes in at the side of the connector block or some people use a needle and insert it inso the top alongside the connector pins then touch the probe on that.

Use a ground screw tag on the corner of the board for gnd may be safest.

You dont measure across pins test each one separately against ground.

[me2space]

Re: Lg 47lh55-ua

The needles work like a charm! This is what I got.

[selldoor]

Re: Lg 47lh55-ua

Well didnt expect that then - Highest voltage should be 20? possible slightly over.
I think its back to the meter - test should be done on next highest scale to what you expect so for all except the 20v one you need to be on 20 VDC and for the 20 next up 200VDC?
Post a pic of the front of your meter. and check the leads are still ok.
Try it out on a 1.5v battery.

[me2space]

Re: Lg 47lh55-ua

Well didnt expect that then - Highest voltage should be 20? possible slightly over.
I think its back to the meter - test should be done on next highest scale to what you expect so for all except the 20v one you need to be on 20 VDC and for the 20 next up 200VDC?
Post a pic of the front of your meter. and check the leads are still ok.
Try it out on a 1.5v battery.

Ok, once again... my fault. I was not able to fix my multimeter as I don't have spare leads. I borrowed an analog multimeter and I overestimated my ability to read it correctly. Based on what you told me regarding the max voltage I should be getting I readjusted the values.

For the 12 volt measurement I was not sure which scale to use so I provided both cases it could be. How I miss my digital meter!

I'm also adding the multimeter I'm using so you can see what I'm working with. I was hoping to find a manual online, but again, it's either too old or too basic to have a manual... I guess.

[me2space]

Re: Lg 47lh55-ua

A service manual that should work for this model is
LG 47LD950C-UA CHASSIS LA92Y

Unfortunately, I can't seem to find it for free anywhere. I have checked the recommended sites...

http://www.tgohome.com/ServiceManuals/
http://elektrotanya.com

Any other good ones I should check? Google is only getting me manuals for purchase.