Samsung Plasma HP-R5052 Won't fully come out of standby

[2dbit]

So, with this tv, I suspect the SMPS has an issue, but I could be wrong. Still learning!

When the power button is pressed, I get a lot of relay clicks on the board, and VA comes to life, but VS and all subsequent voltages don't really come around. (VS hovers around 300mV, I say hovers because it tends to drift as low as 100mV and as high as 400)

The voltages measured on the board are as follows:

(Measured on connector CN804-1)
STD-5V is 5.15v
PS-ON while in standby measures 3.716 to ground, but when the power button is pressed, drops to 6.1mV. This to me sounds like the logic board is happy and is telling the SMPS to fully turn on?

I did see VCA and VCS voltages pulsing, but I am not clear as to what those should be doing, so I am not sure if there is a defect there.

(Measured on CN810)
STD5V measures at 5.15v
VS-ON - 3.339
PS-ON is 3.72v until power button is pressed, then drops to 6mV.

I have tried individually unplugging each board testing and plugging back in, No effect.

I'm to the point where I think I need to unplug absolutely every board from the SMPS and trigger it on. It would seem that all that's required is a jumper from PS-ON to RTN. I have seen where people use a 100ohm resistor. Not sure if that's necessary or not. Haven't done anything yet, so I'll see what this community has to say first!

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

Ok, so the problem was isolated to two blown mosfets on the powersupply board. Well, two shorted Fets, and a blown fuse. Thinking that was it (I have no schematic so when everything around it appeared to be normal I assumed they were the only failure) I ordered two new Fets and a couple of fuses. Put it all together with the output connector removed to protect all downstream boards incase of failure(thank god I did that)and BAM, a few seconds after power application the fuse blew so hard it separated its own case, blowing the top half of the SMD fuse past my head...scary as hell.

Realizing that I'm already out ~$20 in parts on this thing, when I found a "new" power supply on fleabay, I figured it was just easier than dealing with this one. I received the power supply and this thing is far from new. Aside from a thousand telltale signs that this thing has been previously installed in a TV, it had no ESD packaging. It was wrapped in bubble wrap that had packing peanuts static clinging all over when removed from the Zappos box.

Ok, so I give the seller an A+ for effort. It was very well protected within its box from any sort of impact that could occur during shipment. But an F for ESD protection and an D- for product description (hey at least it was the right part).

ANYWAYS. Back to the point. Installed same as the other and powered on. Turns on just fine and puts all the right voltages out. So, I figured ok...lets do this.

Hooked it all up and well...there's at least an image on the screen. Next post will contain pictures of what the new issue is.

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

Here's the current problem with the TV.

It powers up, but the blue screen has white (with some color) snow at the top and bottom. Here's a picture of the blue screen with menu pulled up:





Here's a pic of a Solid black screen (ignore the diagonal shadows cast from a nearby object on the screen)





Here's the signal pattern of scrolling gradient:

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

Bueller...

[tom66]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

Check panel voltages: Vs, Vset and Ve, are OK and measure at stickered ratings.

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

Check panel voltages: Vs, Vset and Ve, are OK and measure at stickered ratings.

I checked and double checked. All voltages are 0.2v or less from sticker

[tom66]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

OK, see if you can find Yfr and Yrr control on Y-main. Try adjusting it. What happens?

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

I will have to do that when I get home. I have a digital oscilloscope, its only 60Mhz, so its under the 200 mark that would be ideal, if I mess with those pots, how can I ensure I get them back to where they belong if they're not the issue?

[anotherdude]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

I will have to do that when I get home. I have a digital oscilloscope, its only 60Mhz, so its under the 200 mark that would be ideal, if I mess with those pots, how can I ensure I get them back to where they belong if they're not the issue?

they are usually marked with a pen to show were they where

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

OK, will report back

[tom66]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

I will have to do that when I get home. I have a digital oscilloscope, its only 60Mhz, so its under the 200 mark that would be ideal, if I mess with those pots, how can I ensure I get them back to where they belong if they're not the issue?

I have used a 20MHz scope to check plasma waveforms, no problem. I always set the pots by eye - looking at the panel for minimum maldischarge point.

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

Ok, so rotating the two pots... the bottom pot (they're not marked) would cause the image to only get worse (fuschia), rotating the top pot, only once rotated to the extreme, would get rid of almost all the snow, but the image is something terrible at that point. On a black screen, the menu is mostly just white. While at minimal snow, rotating the other pot would only add fuschia to the picture.

[2dbit]

Re: Samsung Plasma HP-R5052 Won't fully come out of standby

could it be possible dirty power? Suppose I could always scope it...