LG LED TV Model 42LE5300 not switching on

[budm]

Re: LG LED TV Model 42LE5300 not switching on

if R103 is open then there will be no current flow through to supply the power to the TV during standby mode to keep the TV alive.

[angelos]

Re: LG LED TV Model 42LE5300 not switching on

Hi again,
I am faced with a unexpected problem. I was forced to use 2 x 10nf 2KV caps to make up for the 20nf 800V that's failed but no the cover wont close. This is a slimline TV.
It leaves me to hunt for a part thats not in high supply.
Question 1. According to this power supply's design, can i use a 22nf 800V cap?
Question 2. Of what importance is it to use the right type of cap? I assume mine is a polyester cap, not sure.
There are
polypropylene. polyester, polycarbonate, mylar etc.
Could some cap be bad for this power supply because it operates at such a high frequency?

[angelos]

Re: LG LED TV Model 42LE5300 not switching on

The closest i can get to the physical size and specs is this... Check photo please.
The thing that worries me is the spec 1000VDC and 250VAC
Is the AC specification ok? Isn't the peak pulses going through the cap to ground much higher?

[budm]

Re: LG LED TV Model 42LE5300 not switching on

Can I see closed up pictures of that cap? That cap has to be Polypropylene (PP) to handle high impulse, not polyester type.
Example:
https://www.digikey.com/product-deta...2576-ND/656777

[angelos]

Re: LG LED TV Model 42LE5300 not switching on

I am home now and cannot photograph the cap but it has the marking "MPP" which i googled to be a metal polypropylene type. Out of desperation i took 2 x 10nf 2K caps and put them in parallel, insulated them with a couple of turns of insulation tape. Then i lengthened the caps legs with twin flex and soldered it into the board. Tied down everything to the screen ensuring nothing will arc and avoiding any signal cables. Closed tv. All ok... I am sick and tired of this country. We cant get much variety from our suppliers and if you import anything it takes 4 months to arrive. Welcome to South Africa.

[budm]

Re: LG LED TV Model 42LE5300 not switching on

If it is not PP type then it may not last.
We are spoiled here in the US.

[angelos]

Re: LG LED TV Model 42LE5300 not switching on

I use these caps on the 29" CRT LG TV. This capacitor is used in the line stage and they last since i have had no comeback. I just hope that it can handle the frequency... Oh well, i guess we will find out.
You know, i went to look online at 5 companies to get that cap and not one had it. I then found it on Mouser's site but thats again an import..... I love the callenge but abhor what this trade has become. To think back to the beggining. I dont know if you are familiar to the Philips tvs that came out in the late 70s, it was a K9 chassis then later came the KL9. Those service manuals were 40 to 50 pages explaining everything. They had voltage test points and oscillograms of the entire tv... now fast forward to todays crap. No circuit diagram on purpose left out so that few can repair their products so that the factories can churn out more and more tv's. I also remember that the government would force manufacturers to keep stock of spares for 10 years. Now there is no such policy. Do you experience a similar trend in the states?

[budm]

Re: LG LED TV Model 42LE5300 not switching on

Do you experience a similar trend in the states? Yes, in the 70'SA I was using SAMs Photofacts for lots of schematics, but those days are gone, they just want you to buy new stuff when the old one breaks down.