Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

[Aiove]

Done a check over on all the boards, can't find any burn marks or colour change on any boards, no caps have bulged out(haven't actually tested any yet as i'm unsure how to) checked fuses

When it turns on there's a click from the relays on the psu, as when it's turned off, the chime plays for it turning on and then there's no picture or glow.

the logic board has an led that lights up for 5 seconds and then off for 2, according to this page,

http://www.tgohome.com/ServiceManual...shooting(map)_[SM].pdf

This means DRV_RESET but doesn't explain what that actually is..

I've tried testing voltages but either im doing something wrong or there's something broken because im getting 10 or so volts at Vs and .15volts at Va, both going down slowly. Seeing a lot of post about voltages going down is usually a stuffed cap.

What can i do to further test the tv?

thanks

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

Can you post a picture of the chassis and one of each board?

Link to file - the [SM] in the URL confuses this forum - so use this instead:
http://www.tgohome.com/ServiceManual...&Search=Submit

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

let me know if you need clearer pics and of what

https://www.dropbox.com/sh/4t8zukek0r36ef5/81EMZnn63s

there's still 2 or 3 uploading at the moment, will be done in a minute

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

Reading manuals on tgohome.com and one says if Va Vs are low remove both sus and see if the voltage rises

neither did on Vs or Va, both drastically reduce to nothing either all plugged in or one or the other unplugged

I'm starting to think it's the power supply, is there a simple way to test this?

and if it is the smps what can i do to isolate the faulty part? im not too sure how i can check for a faulty transistor or capacitor with a multimeter

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

You can load Vs with a 240V, 100W lightbulb. Are those still legal in Aus?

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

im not sure what you mean

will a lightbulb load cause the power supply to do something different?

does drv reset actually mean anything?

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

I don't know about DRV RESET.

The light bulb will provide a load on Vs so you can see if it remains high with just the lightbulb connected.

Note - this chassis will shut down if it does not detect Y-main/X-main are working, so you need to force VSON high or low (and PSON high or low), I think it's low on this chassis, to turn outputs on.

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

if i start the tv up with both boards unplugged and it acts the same, the fault isn't in those boards yeah?

also im not sure how i would "force vson"

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

There is a connector from the PSU to the control board right? Is there a pin marked VSON on either side?

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

yup, can see it

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

OK, and you see PSON?

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

yup, so jumper wire between those two pins? on which side?

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

Between PSON and GND, and also do VSON and GND.

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

so leave the connector on the psu and short the pins from the other side?

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

It should be disconnected from main board/control board and connected to PSU.

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

PSON shorted to ground,

No glow, no picture, plays start up chime
Vs constant 10volts, doesn't drop
Va 0.14 volts, doesn't drop

VSON shorted to ground

No glow, no picture, plays start up chime

Va, .12 volts
Vs, 10 volts

plugged power cable back in to main board and now there's no voltage

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

at Va or Vs*

[tom66]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

Sorry if I wasn't clear, you should do VSON and PSON at the same time, both are necessary. Do not expect to get a picture with main board connector unplugged -- screen -may- glow though depending on chassis design.

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

ah okay i'll try that

[Aiove]

Re: Samsung PS50C550 (S50FH-YB06) Sound but no picture (or glow)

everything except Va is the same, Va was at .20volts, don't think this means much since its meant to be 55volts....