LG bh9530tw home theater no power

[Khron]

Re: LG home theater no power

https://en.wikipedia.org/wiki/Silicon

"Not to be confused with the silicon-containing synthetic polymer silicone."

https://en.wikipedia.org/wiki/Silicone

Start with the ones on the secondary side, connected to that transformer. Then the ones on the primary side.

[Rain0989]

Re: LG home theater no power

With silicon you mean the yellow glue ? And which diodes?

Best regards

[Khron]

Re: LG home theater no power

Start checking the silicon, then - diodes, to begin with.

[Rain0989]

Re: LG home theater no power

SO i have the capacitors here and changed. But still no standby or anything. Almost dead....

[Rain0989]

Re: LG home theater no power

I have ordered now 3 new low esr Capacitors.

C909 and C936 are 50V 22u and the C919 is 50V 47u.

When they are here i will replace them and write here again.

[Rain0989]

Re: LG home theater no power

Thank you I will Change the capacitors and write then again here

[Khron]

Re: LG home theater no power

I can't really see the values from the photos you've posted.

No, i don't have the schematic, but for sort-of-"textbook" circuits like these, manufacturers rarely make things much more complicated than the datasheet examples of the chips they use. In this case, that 7-pin chip driving that transformer seems to be a Sanken STR-A6053M.

https://cdn.badcaps-static.com/pdfs/...ae6914545d.pdf

Example schematics are on page 12.

C909 is most likely the filter capacitor for the chip's Vcc line (C2 in the example-schematics), so that would be the prime suspect, given the symptoms. Something like a 47u/50v should be fine, in that position. C936 may well be a similar value, and the fatter one between them, possibly 100uF/50v (the voltage rating is visible).

[Rain0989]

Re: LG home theater no power

You know the capacitors farad and volts that i need? Then i can order they directly now. Otherwise i must wait until tonight when i am back home after work.

Do you have the schematic maybe ?

[Rain0989]

Re: LG home theater no power

I will change the three capacitors and see whats going on after this and then i wil lwrite here again

[Khron]

Re: LG home theater no power

... Which may well be an indication of the "hiccup"-mode the PWM chip is in, not being able to start and keep working.

So either (one of) those three capacitors i indicated has failed, or (maybe a bit less likely) there's some shorted diode on the associated secondary.

[Rain0989]

Re: LG home theater no power

I will replace C909, C919 and C936 with new low-ESR ones and measure the voltages again and look if i can turn on the player.

Actually i can not turn on the Player its dead. I will write here again after i change the Caps.

[Rain0989]

Re: LG home theater no power

The voltages that i measure are not constant. They jumping from for ex. 4-16v etc...

[Khron]

Re: LG home theater no power

For starters, i'd replace C909, C919(?) and C936, preferably with name-brand, low-ESR ones.

And how far off are the voltages you're measuring?

[Rain0989]

Re: LG home theater no power

So here are another two pictures.


I measured the voltages on the PCB board on the contacst you see on picture 1. But my measure doesnt match with the voltages written on the PCB.

[Rain0989]

Re: LG home theater no power

That is positively irrelevant, especially in those smaller can sizes. Just because they haven't exploded, doesn't mean they haven't dried out and/or dramatically lost capacitance.

https://en.wikipedia.org/wiki/Bootst...power_supplies

Ok should i replace all caps ?

[Khron]

Re: LG home theater no power

That is positively irrelevant, especially in those smaller can sizes. Just because they haven't exploded, doesn't mean they haven't dried out and/or dramatically lost capacitance.

https://en.wikipedia.org/wiki/Bootst...power_supplies

[Rain0989]

Re: LG home theater no power

The caps looking all good...

[Khron]

Re: LG home theater no power

"Ye olde" crapped-out start-up cap problem, perhaps?

[Rain0989]

Re: LG home theater no power

This are the pictures of the board i have on phone. Better pictures i can make when i am at home.

[Rain0989]

Re: LG home theater no power

So what exactly is wrong with YOUR power supply, maybe we can figure it out. Post a picture and list what parts you have found that are defective so far.

Hey thank you for your patience

I will make pictures tonight and upload these here

My Player wont turn on. Nothing happen when pushing the power button on the remote control. No lights nothing