50PC1d power board

[tom66]

Re: 50PC1d power board

Sorry, miscommunication - the whole of the back of the PSU. Everything.

[caspermccormack]

Re: 50PC1d power board

PSU front


PSU rear

[tom66]

Re: 50PC1d power board

By the biggest capacitor on the board with the black cap (not the two next to each other), is there anything on the heatsink? If so, with the power off and board removed from the TV, check all the pins of the devices mounted on this heatsink using your meter on diode test. Try all combinations, note the pins down. There should only be two devices. If it makes it easier, post a closer up picture of the bottom side of this area so I can highlight things to test.

[caspermccormack]

Re: 50PC1d power board

There is two heatsinks beside that cap, I take it you are looking at the long one, it has 2 pin (red) mosfets? and 3 pin (green). Looks like there is some smudge of heat contact paste there too.

[tom66]

Re: 50PC1d power board

Yep, that's the one. Check all the devices there. I suspect one is shorted.

[caspermccormack]

Re: 50PC1d power board

Yep, that's the one. Check all the devices there. I suspect one is shorted.

So far I have checked the 2 pins, There are 5 on the heatsink, 4 give the same reading on diode test one way they climb to 3.2 before OL and reversed 0.3. The one that shows the difference reads 0.3 and 0.5 the other way.

I'll take a look at the 3pins now.

Nice one buddy.

[caspermccormack]

Re: 50PC1d power board

two of the 3 pins seem to be doing the same readings, and the other 1 has completey differrent reading but it is a different part number. If I knew what exactly what to look of on the multi meter it would be great help.

Again thanks Tom.

[tom66]

Re: 50PC1d power board

two of the 3 pins seem to be doing the same readings, and the other 1 has completey differrent reading but it is a different part number. If I knew what exactly what to look of on the multi meter it would be great help.

Again thanks Tom.

On diode test, a diode should show from 150 to 700, or 0.150 to 0.700.

If the diode shows <30 in any direction, or the same readings in both directions for any pair of pins, it is probably bad.

[caspermccormack]

Re: 50PC1d power board

I have the heatsink out with the diodes attached,

5x 2pins All show reading one way and .OL the other
1...0.409
2...0.383
3...0.383
4...0.372
5...0.372

3x 3pins

2 of which are the same part number (B0669 F30SC6)

Black probe on the centre pin, and red on either end pin show the same value.
0.124, 0.122 on one and the same test on the other 0.121, 0.121.
.OL on any other test.

the last 3 pin (BH06 FQPF 27P06) reads 0.528 red probe center and black on the right, all other ways .OL

Hope that makes sence??

[shepp]

Re: 50PC1d power board

#20 replace with same type 22n cap

then retest

[caspermccormack]

Re: 50PC1d power board

#20 replace with same type 22n cap

then retest

I'll check that out, cheers. Do the values of the diodes on my last post seem OK or do I need to change any of them??

[tom66]

Re: 50PC1d power board

The diodes seem okay. You are looking for <0.03.

Next resolder the diodes. Are there any small capacitors on the primary side of PSU?

[caspermccormack]

Re: 50PC1d power board

I replaced the blue 22u cap now I have 189v and 60v outputs from the board!!! deadly.
So now I have the screen on but its very fuzzy random pixels, is it a matter of tuning the set up now??

[caspermccormack]

Re: 50PC1d power board

So this is where I am now. Thanks for all the help!!! Any more info on what else now needs doing?

http://www.youtube.com/watch?v=UqutIxlStk8

[vinceroger69]

Re: 50PC1d power board

whats the picture like when you have the on screen menu on? is it worth trying a factory reset in the sevice menu?
To get to the service menu hold down the 'Menu' button on the TV and the remote control at the same time for about 3-5 seconds. The menu will then appear

[tom66]

Re: 50PC1d power board

It looks like a failed buffer (or buffers), but I'm not sure. Check the control cable from buffers to Y-sustain is properly seated, as well as the main connector.

[caspermccormack]

Re: 50PC1d power board

Vinceroger69, got the service menu up but could only see a fat white line from top to bottom on the lefthand side.

Tomm66, I was looking at voltages on the y board out, VSC check point was pulsing 1.0 to O.L. After the buffers disconnected it was 120v as it should. The -VY check point which is meant to be -200v is reading 200, unless I switch around the probes. Also there should be a readingof 18v from the IPM and I am getting 16.2. Is there a way to check the buffer boards?

[caspermccormack]

Re: 50PC1d power board


Troubleshooting guide

120 here when the buffers are disconnected

Can only read -200 if the probes are reversed on the check points

[tom66]

Re: 50PC1d power board

-Vy is normally negative, that's good.

The lack of Vsc suggests a failed buffer. Remove the buffer boards, then set your meter to the 2000 ohm or 2k ohm range. Check between each of the large contact pads and report the resistance. If this TV has separate buffers, try with one and then the other to see if you can get half a picture back, although that doesn't always work.

[caspermccormack]

Re: 50PC1d power board

Top buffer is showing O.L in either direction, and the bottom one is shown 29.7 and 30.0 the other on my multimeter.