17pw15-9 Wharfedale 37" LCD

[Loz2212]

Hi guys,

Having an ongoing nightmare with this tv... Basically it starts crackling from the speakers and the PSU (assuming a transformer?) and will occasionally turn itself off and flicker on and off.. I changed every possible part on the PSU as advised by other posts on here... Occasionally it would behave for a while and then start again... Ended up ordering a new PSU which improved the symptoms but now they're back.

Seen people mention about PFC fault but I've changed the PSU. I've measured voltage across the main cap which is perfect and other times it sends my meter mad and turns the TV off. By pushing and moving the PSU and main board it alleviates the symptoms for a short while until they return.

Any ideas?

Thank you.
Loz.

[dick_barton]

Re: 17pw15-9 Wharfedale 37" LCD

What model is it. How long did it behave itself with the replacement PSU. Do you have any photo's of the boards?

[ReeceyBurger123]

Re: 17pw15-9 Wharfedale 37" LCD

What voltage do you get across the mains cap ? It should be measured in 600v dc mode, I have serviced alot of these supplies the replacement is probably bad as well.

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

Thanks for the replies. Model is LCD3710HDAF. Pictures are actually on my previous posts on this subject haha.

https://www.badcaps.net/forum/showthread.php?t=52422

Reecey I hope you can be my saviour again... 392 VDC but it turns the tv off when I do it. Takes a few attempts which is bizarre. It's like it can't correct the slight drain of my meter and cuts out.

After fitting the new PSU it worked for about a week but it did that before anyway. I'm no stranger to buying already broken boards so more than happy to consider that however the fault Is still exactly the same.

Thanks guys.

[dick_barton]

Re: 17pw15-9 Wharfedale 37" LCD

I can see no reason why attempting to connect your multimeter probes across the two pins of the cap should reset the set other than a possible fracture in the connection between the pcb pad and the capacitor pins which is disturbed when you attempt to probe the pins.

However you say it's a different power supply so I can't see that being the problem. Have you checked the solder joints on the mainboard connector that's connected to the power supply or checked that none of the pins of the mainboard connector are damaged in any way.


Edit
Looking at the picture of the power supply is the bottom of the board well clear of the chassis or does it have a plastic protection film under it to insulate it from the metal chassis.

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

Main board hasn't been removed at all but I'm assuming that's the next step. Very bizarre. I take it this isn't a known problem with this power supply? Lol.

[dick_barton]

Re: 17pw15-9 Wharfedale 37" LCD

I recognise the power supply and 99% of the time the only problem I've ever had with them has been bad capacitors.

[ReeceyBurger123]

Re: 17pw15-9 Wharfedale 37" LCD

Plenty of known issues with these supplies, my first step would be to check what the 24v rail does when it messes up.

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

Cheers Reece. No labels on the board so assuming 24v is to the inverters? Measured it and it's sat at bang on 23.5v but that's without it playing up. I'll message with the results when it next happens.

[ReeceyBurger123]

Re: 17pw15-9 Wharfedale 37" LCD

Ok mate try heating the Psu with a hairdryer and see if it messes up faster, Im certain this is a Psu fault here.

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

Another thing... Might sound strange but when I was playing Fallout 4 it would do it and then when I paused the game it would stop...?

[ReeceyBurger123]

Re: 17pw15-9 Wharfedale 37" LCD

Lol probably because its not having to do as much Lvds and Hdmi processing which uses more power as moving images, not to forget active backlight dimming etc. You got an image of the whole backside of the set ?

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

Right I'm with ya. Yeah just that one from the link above.

https://www.badcaps.net/forum/showthread.php?t=52422

Found a main board on eBay for £3 including postage... Like you say it's probably not that but for £3 I couldn't grumble. It's behaving now as I lifted it onto the floor to have another look

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

I'm back again haha... Main board on and tv as usual worked fine for a week and now it's doing the same thing. Fit PSU and main board, audio begins to crackle and then goes completely. By tapping and wiggling the wires on the PSU it comes back and then goes. Checked for cold joints and bent pins etc... TV switches itself off when I measure across main capacitor. Output voltages all seem fine... 24v, 5v and 3.3v. Voltages at speakers drop during the crackling... I thought it could be a faulty sound board but why the hell does the TV turn itself off when I measure across the main cap?

Thanks guys.

[ReeceyBurger123]

Re: 17pw15-9 Wharfedale 37" LCD

Sounds like cold joints, normally several Smd resistors in the Pfc area.

[Loz2212]

Re: 17pw15-9 Wharfedale 37" LCD

Should I not be suspicious that it's the same fault on this PSU as well though Reecey? What a rubbish set of boards these are...

As always thanks for your response.

[ReeceyBurger123]

Re: 17pw15-9 Wharfedale 37" LCD

Its got to be a Psu or wiring fault, got to rule out every possibility. Resolder the Smds on the Psu first.