LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

[budm]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

Can you use pass transistor setup with the 317 so it can handle more current?
Or get some cheap like this:
http://www.ebay.com/itm/3-3V-AC-Adap...ht_2942wt_1185

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

[Duplicate post...]

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

I've decided to use an LM1084, I'm ordering components soon. I'll use the circuit I've drawn below.

Some power resistors (R1,R2) are used on the input to reduce the dissipation in the regulator. They are sized for maximum 1.8A current, but could dissipate a lot more power. Also it switches over to 6V rail if that is available,

Tomorrow I will fully test the current drawn when using the digital TV (Freeview) function, and the HDMI, as I am not yet sure about the current drawn.

Edit: I'm not sure I can use an LM317T with an external transistor because the dropout is greater and everyday transistors don't have thermal protection, I want to make sure the regulator does not overheat and damage itself.

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

Okay, this TV is not very power efficient! Like that 26" LG you have on your Photobucket bud, but a bit better. It draws about 3W in standby, mainly because the 3.4V_ON is always high. The 3.4V output is used for the remote control

Standby current: 0.44A (1.45W)
Startup current: 1.3A peak
Run current composite/SCART input: 1.43A (4.72W)
Add for HDMI connected (whether active input or not, or even in standby!): +0.15A (+0.5W)
Add for Freeview/DVB-T: +0.1A (+0.33W)

The 3.4V needs to be high for Freeview and HDMI to both work, or the TV just says "No Signal" or "Weak Signal".

[budm]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

I did not check to see what the standby power draw is yet, I think it will be just as bad as the 26" since it has cable card slot. I will check it later on today.

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

I hope the UK model will be better, but I think it's ridiculous it uses 2-3W in standby. I have an 8 year old Pioneer 50" plasma that uses 0.3W in standby! How much do some pFETs cost for controlling power to the other parts like HDMI? The fact that it draws so much in standby shows that very little is being switched off in standby mode.

I need to get myself a Kill-A-Watt to test these things.

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

So, I got the stuff for the board finally, and have now built it up and tested it.

Stable 3.3V under no load, drops to 3.24V under load but remains stable up to around 1.8A. I had to insert another resistor-diode pair to reduce the drop across them.

I need to change the battery in my BK meter, the indicator just lit up. It eats up batteries in about 4 months, even good alkaline ones.

I will find out tomorrow if it works.

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

Damn, I'm an idiot. I shorted 6V to GND and blew a mosfet on the 6V DC-DC. Aghhh. I've found a cheap power supply spare and will probably just replace it with that.

[psmedley]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

Damn, I'm an idiot.

You may have made a mistake - but you are NOT an idiot!

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

You may have made a mistake - but you are NOT an idiot!

I didn't check the soldering. A little splash of solder. It will only cost £32 for a new PSU though... which including £40 for the TV, isn't too bad.

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

New PSU fitted, TV works great , sound, Freeview, HDMI etc all work. PSU board looks almost new - no browning etc.

[budm]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

That is great, mine is still working so far, but I will keep my eyes on it.

[tom66]

Re: LG 37LC2D No sound, picture okay, remote control and side buttons glitchy

My dad gets to keep it for at least a week before it is sold. So I'll see how well it goes. The original PSU lasted 5-6 years according to manufacture date.