LG 42"Plasma - no power

agentsmith

Hi - recently TV wont power on - see below details and queries.

LG PLASMA 42PX3RVA-ZG
Model: PDP42V706A2 (Date 2005.10)

Fault
Plasma TV fails to turn on – NO audible clicking or power indicator lights on TV. Unable to operate either by remote.

Troubleshooting
Checked the TV power cable (continuity test and used different cable) - OK
Confirmed 230+ v supply to PCB with multimeter - OK. Power also getting to Tuner board (see red light in pic).
Conducted visual check of all boards - some of the capacitors on the Sanken Power PCB look slightly bulged on the top (see attached pic), with some apparent staining on one or two (beside st-by Trans T121) otherwise no obvious leakage or side swelling.
Conducted continuity checks on all the fuses on the boards - OK.

Questions
Are the pics of the capacitors indicative of having failed or only on the verge of failing?
If capacitors failed, are these the cause of the power issue and TV fault?
What might the cost of repair be and work involved? Replace capacitors or complete new power board?

ozmo

Definitely the capacitors are gone, you can see the the split in the photo - hopefully they didn't take anything else out as they blew... is there any other sign of damage on the board? if not it might be worth just replacing the caps.

They are not too expensive to replace if you can solder them yourself - just be sure to get decent branded ones - you can buy a ready made pack of all the correct ones for many tv's on amazon.co.uk or else where. Best replace them all even if they look ok.

agentsmith

Cheers ozmo -how many do you reckon gone from pics looks like maybe 2-3?

Any chance you can direct me to where might be able to find 'ready made pack' as cant seem to find on web.

Board P/N: 6709V00010A YPSU-J006A.

Seems replacement boards also hard to souce as any links showing out of stock.

The rest of the boards to my eye seems to look ok - and given obvious cap failures can probably rule out other consideration of faulty power switch?

ozmo

>how many do you reckon gone from pics looks like maybe 2-3?

I would say all of them would need to replaced - to fail like that they are either poor quality, underspec'ed or most likely just overheated - as all caps would have been under the same stress they are likely all gone or about to. You might get by replacing just some, but i would replace them all as they are not so easy to test - they are not expensive.

Where to get them?

Try search something like this - and make sure all the caps you need are in the pack

http://www.ebay.com/itm/LG-42LC2D-TV-LCD-Monitor-CAPACITOR-Repair-Kit-Replacement-Parts-Only-/161387523470

there are packs that include the soldering iron as well if you don't have one.
http://www.ebay.com/itm/LG-37LC7D-UB-TV-LCD-Monitor-CAPACITOR-Complete-Repair-Kit-w-Solder-Iron-/161268740082

The above links are LG - but you will need examine yourself if you get all the bits you need for your model and the quality looks ok - you might get a similar kit closer to home eg. Maplins or RS if cost is not an issue.

agentsmith

ok thanks - have removed power board and see evident damage to a number of the caps in addition to obvious top blown ones - side splitting. wonder if beter replacing board instead. Is it likley other boards damaged also or typically just damage on power board?

PeterTheEighth

agentsmith wrote: »

ok thanks - have removed power board and see evident damage to a number of the caps in addition to obvious top blown ones - side splitting. wonder if beter replacing board instead. Is it likley other boards damaged also or typically just damage on power board?

It's a judgment call. Count up how many capacitors you need and then price them on radionics.ie or ie.farnell.com. You would probably have to buy the board from somebody in the UK like emoTVs so there will be a shipping cost as well... or you might get lucky and find somebody on adverts with one.

There is no way of testing the other boards without a working power supply. As a matter of interest, did this problem happen all of a sudden or has the TV been slow to power on for a while?

agentsmith

OK thanks.

All of a sudden issue but must admit when think about it sometimes was a few seconds to start up when press power button - whats the significance - evidence of failing board/caps or other part?

PeterTheEighth

agentsmith wrote: »

OK thanks. All of a sudden issue but must admit when think about it sometimes was a few seconds to start up when press power button - whats the significance - evidence of failing board/caps or other part?

Well there's a known trick that if you suspect there is an issue with the capacitors. Turn on your hairdryer and move it in a circular motion above the suspected capacitors (to heat them up), and see if the TV comes on. This could help you confirm i) The capacitors are the only faulty components that you need to replace and ii) that all of the other boards are functioning. It's not 100% proof of i) or ii) but certainly a good indication.

agentsmith

might give it a try

PeterTheEighth

agentsmith wrote: »

might give it a try

Yeah, I had one similar to yours. But it's not a common failure. Most of them try to come on and you hear the dreaded click, then rapid unclick of the mains relay when it notices there is a problem.

But the one that I had, had the same bulged capacitors. There was a faint LED on the front of the TV but no response from the remote. Checked the standby voltages and they were very low, less than 3V. Swopped out a few of the standby voltage caps and it started working again.

Hopefully yours will be something similar. The last thing you want is to put money in to fixing the power board only to find that the main board is gone as well. :mad: