ps50q96hd no picture

[tom66]

Re: ps50q96hd no picture

tom the last person that messed with this has a 1000uf 35v this is one right nr ymain power connector and fuse


would this be bad

Well is it a low esr capacitor? Probably not the cause of the problem but difficult to tell. Btw, "SD" capacitor is NOT suitable!

[wreksta]

Re: ps50q96hd no picture

ok tom what shoud I cange it for whatsoriginal value infact do you know all the origina values of caps as I think this idiot has spooned it using what he could lol

[tom66]

Re: ps50q96hd no picture

I do not know the original value.

[wreksta]

Re: ps50q96hd no picture

tom tested the the green small fuse on xmain I get 206v both sides this is with set powered
y main I get 015von that little green fuse both sides could this fuse be my problem

[wreksta]

Re: ps50q96hd no picture

I went ahead and replaced that fuse now I have vscan up to -194 but when I plug control board flex ribbon back into the ymain I get green light on the ymain
so if I have the x and y al powered without the control boards flex cables I get correct voltages at vs and va and vscan voltage is right but why wont screen light up I cant go ahead to fault find if the panel don't fire can I?

or coud something else stop the panel lighting up

[tom66]

Re: ps50q96hd no picture

The LED will light up if the Y-main encounters a fault, when it does the control board shuts it down. Faults can occur due voltages being out of spec or a short being present on the board.

Voltage both sides of a fuse is fine, 15V is fine for the small fuse.

[wreksta]

Re: ps50q96hd no picture

so whereto look now tom

the way i get no led and on par voltages with panel sticker is both ribbon cables on lower of xmain and ymain disconnected

if i connect them up y main goes into protect mode with led what i can gather is the ymain ribbon cable connectes to control board and xmain to lower buffer boards

is this correct
please assist thanks

[tom66]

Re: ps50q96hd no picture

That is expected behaviour; there is a fault on your y-main board. Follow the mosfet testing tutorials previously linked. There is no silver bullet. Without testing everything you cannot locate the fault.

[wreksta]

Re: ps50q96hd no picture

mate like I said I need a dummies guide could you illustrate how to test them in circuit using one of my pictures I know its a lot to ask but mosfets have thrown me so until I learn I cant get better

and for clarification the ymain and top/bottom buffers these used to light screen with out functioning ymain no glow

[tom66]

Re: ps50q96hd no picture

No y-main = no glow and picture
No y-upper = upper half no glow no picture, bottom half picture maybe depends on design
No y-lower = lower half no glow no picture, top half picture maybe depends on design
No x-main = minimal or no glow, faint/distorted image only

I'm not sure how I can help you more than this guide; it's exactly what I would suggest. Simply follow the instructions. You can't go wrong:
http://www.4qdtec.com/mostest.html

A simple test across D-S can rule out 90% of MOSFET failures. Identify D-S by googling part number such as 98N30W and selecting the datasheet.

[matyka]

Re: ps50q96hd no picture

hello,I have the same tv and will not power on just cliking .
I have a good power supply ,if you cold start it have good readings.
The problem is when plug in only the main board and the CONTROL BOARD to the psu the tv just clicks ,is the main board faulty ?
Is this tv should start only with this 2 boards connected ?
thanks

[flocko]

Re: ps50q96hd no picture

Do not understand ,what do you mean cold start? what voltages are you seeing from the power board ?we need to know what do you have on the PSon from mainboard and what you have at VSon from the control board. The PSon from the main should be high (3v)when in standby, Then when you turn the set on with the remote or side button PSon will go low (0-1v) and should remain low, Vs on will be low in standby and high on start and remain high for your supply board to work

[matyka]

Re: ps50q96hd no picture

I mean turn on PSU without main board and control board by shorting 2 pins together .vsON/5vStB and psON/RTN I have good reading from both VA-63.2v and Vs-207v

After I try to connect the control board and main board to the PSU I hear the clicking and shuts off .

What is the next step please ?
Should the PSU start with only this 2 Boards connected to the power supply ?
and no x,y,buffer board connected ?

I am thinking the main board is faulty (already changed the ic 24C256BN )

[tom66]

Re: ps50q96hd no picture

Check 15V, 5V ,etc. as well when you jumper -- cold joints can cause these to go missing.

[matyka]

Re: ps50q96hd no picture

Just jumped again and you can see in the photos all have good readings including CN801 and CN807 connector .

What would be the next step please?

[flocko]

Re: ps50q96hd no picture

so tell us what are you getting on PSon + VSon that I ask you for with main and control connected ?

[matyka]

Re: ps50q96hd no picture

when I connect the main board and control board it start clicking and wont stay on.

[flocko]

Re: ps50q96hd no picture

Yes you have told us that but what voltages are you seeing for PSon +VSon ,we know now the power board is working so lets see what is not ,trying to see if its the main or control, board that's the problem, when you test give us the standby voltage and the voltages when you power on, it may only go up for a second or so then back to standby voltage

[matyka]

Re: ps50q96hd no picture

I have put back the power board ,connected the main and control board
the readings are :
standby :5.137v stay on all the time
PSon : 3.416v when clicks drops
VSon : 001.5mv no reading

[flocko]

Re: ps50q96hd no picture

so no VSon from control board try with just main board connected / I would expect the power supply relay to click and stay in but with only low volt outputs from it no VS