Turning the TV on with the computer via a relay??

[Scumgriever]

Ok guys, just a quick check to see if this is going to work.

I need to get my TV to turn on with my computer so that the cab comes alive all at once. I’ve built a relay based power board for the marquee light and speakers like the one Spystyle has up here - http://spystyle.arcadecontrols.com/01/index81.htm . That’s up and working which was very exciting seeing as I have VERY limited electronics experience.

Anyway the problem I’m having is that When the TV is given power at the plug it doesn’t come on. It needs to have power at the plug and then have the main switch at the front pressed. This switch isn’t the momentary type, (it stays in after being pressed once and pops back out again when its pressed again to turn the TV off)

It is not the switch to put the TV on ‘standby’ so to speak. That function is only available from the remote. It seems to be a true on off switch.

What’s giving me the troubles is that even if you give the TV power when the switch is pushed (in the on position) it wont come on. The switch needs to be switched while the TV is plugged in.

So, I was thinking of wiring another relay into the power switch on the TV.
See the pic for how I’m planning to wire it.

Considering my lack of experience I figured it’d be best if I jumped on here and checked that this will work before I massacre my TV... more.

I’m 99% sure that the switch connects the blue points together and the red points together (see pic) but is it possible that it goes the other way? Connecting sideways?

Anyway, Can anyone see any reason that this won’t work? I’m not at all confident but very hopeful.

[ChadTower]

That would probably work if you wanted to duplicate the function of the power button automatically.  I'd be tempted to see if I can't figure out why it needs that to happen and eliminate it.

[Kevin Mullins]

I agree... that would work for the power switch since it's a mechanical "on-off" type switch on the tv as I understand the way you describe it.

My question is: What is the tv's power cord plugged into?
If that power source is switchable on and off then why not just leave the tv's power button "ON".

Just trying to understand the rest of your setup.

[ChadTower]

The description makes me think it's a two seat momentary contact switch.  It only ever makes contact momentarily but it can be pressed in or out so a person can see if the TV is off or on.  Why they couldn't just look at the screen, no idea.

Trace the wires back from that little PCB and see if maybe you can't just short whatever it is connected to to keep it on.

[Scumgriever]

I'd be tempted to see if I can't figure out why it needs that to happen and eliminate it.

I've been tempted to do all sorts of things but my skills need work.
just getting the computer to turn the telly on will satisfy me nicely.

Just for arguments sake though ... any ideas?

I agree... that would work for the power switch since it's a mechanical "on-off" type switch on the tv as I understand the way you describe it.

I'm not 100% sure it is this type of switch but I assume it is because of the action of the button.

My question is: What is the tv's power cord plugged into?
If that power source is switchable on and off then why not just leave the tv's power button "ON".

The TV is plugged into one of the normal sockets on the pwerboard, meaning that it gets power all the time, although I could just as simply plug it into one of the 'relayed' sockets
I can't just leave the button in the on position because it won't work that way. The switch needs to be pressed after the TV has power...
which worries me making me think that it just might be a momentary type switch after all...
but then you'd think that the in = on, out = off would get all switched around if the button was pushed while there was no power to the TV. this is not the case.

The TV is an LG A59KYL220X 06 according to the sticker on the tube if that will help anyone figure out if this will go ok for me.

[ChadTower]

It's almost certainly a momentary contact switch.  The question, I guess, is how many contacts it actually has.

[Scumgriever]

The description makes me think it's a two seat momentary contact switch.  It only ever makes contact momentarily but it can be pressed in or out so a person can see if the TV is off or on.  Why they couldn't just look at the screen, no idea.

Trace the wires back from that little PCB and see if maybe you can't just short whatever it is connected to to keep it on.

I'm not at the same place as my cab at the moment but from memory...
The PCB only has 2 sets of wires coming out of it. one red and black and very thin which connect to the PCB near to the connection for the LED and IR receiver which I assume are 5V or maybe 12V and another much heftier pair which go to the main PCB which muct be the main power line.

I was thinking initially of just bypassing the little switch PCB entirely and wiring the plug to these two wres but if this doesn't also bypass the 'need to push the switch while the TV has power' thing then i'm up a suspiciously brown creek without a TV.

[ChadTower]

The TV isn't running on 5v or 12v.  You should be able to get an idea of the purpose of those wires by their gauge.

I'd trace what is in between those two hefty wires and figure out what that stuff in between is doing.  It's possible you can just short those two lines and bypass the need for the switch.

[Scumgriever]

The TV isn't running on 5v or 12v.  You should be able to get an idea of the purpose of those wires by their gauge.

I'm sorry, I don't know gauges. They are the same thickness as the wires coming from the power button of a computer... thin that is.

I'll have a closer inspection of the PCB tomorrow but the back side of the power button has a hulking great metal cover which blocks everything from view. I thought I had a photo but it seems to have dissapeared.

[releasedtruth]

Any reason not to just use a Bits Limited Smart Strip? I mounted a hidden momentary switch and when you press it the PC/marquee/leds/TV/amplifier all come on and when the pc powers off, it all goes off. Plus it's a super nice surge supressor.  But yeah, looks like that would work

GT

[ahofle]

He built his own smart strip.  The problem is the TV won't go on when power is applied to it via the relay (my crappy TV does this too, so I'm interested to see if this can be hacked).  The other issue he may have is whether or not the TV remembers the last input selected (AV1 or whatever).  Mine also doesn't do this. 

[ChadTower]

Definitely a candidate for getting a different TV.

[Kevin Mullins]

It's almost certainly a momentary contact switch.  The question, I guess, is how many contacts it actually has.

Hmmm..... now that he has mentioned that you HAVE to absolutely push the button to turn it on after power is applied it most defineately is a momentary switch.
Odd that it would have an IN / OUT detent like that though.
None the less, if it is momentary you might possibly try "holding" the power button down, as if you were turning it on, but don't let go..... THEN apply power by plugging it in. This should at least verify if it will be bypassable. (some require that you actually let go depending on the circuitry of the tv itself)

[Scumgriever]

The other issue he may have is whether or not the TV remembers the last input selected (AV1 or whatever).  Mine also doesn't do this. 

That is a problem I have but got around. The TV comes on to Ch1 everytime. I got a cheapie modulator from Jaycar for $15.https://secure4.vivid-design.com.au/jaycar2005/productView.asp?ID=LM3873&CATID=31&keywords=&SPECIAL=&form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=372 I just plug my AV cable into that, tune the channel into one of the selectable frequncies on the modulator and hey presto!!!!

now if only the TV would turn on...

some require that you actually let go depending on the circuitry of the tv itself)

I cant check untill tomorrow, maybe monday depending on how things go. but if it turns out that it needs to be pushed and released am I stuffed?

There must be a way around it...

[Scumgriever]

Also if it is a momentary switch, will using the relay to hit it like I described in the first post of this topic kill it?

[Mark70]

Can you find another model number on your tv.  I didn't find much when I googled that number.  It turned up on a list of tv parts.  Maybe the actual tube number itself.  What about a tv model #.

On a side note, I have a JVC tv with one of those one position type switches.  My surround sound amp has a special socket which will turn the tv on.  Not sure how, but it does it.  I'm not suggesting that you put an amp in your cabinet.  Just find out how that's done.

I built spystyles relay based smart strip too.  I love it, but no problems since I'm using a computer monitor.

[Scumgriever]

I'll check the model number agian when I get back to the workshop.

Which probably won't be till monday,  though I might find a bit of time tomorrow. I have kinda hacked the case up (hence why I used the number from the tube assuming they'd be the same) but all the bits are still around so I'll find the model number with a little rummaging... I'll get back to you on that one.

[Scumgriever]

Can you find another model number on your tv.  I didn't find much when I googled that number.  It turned up on a list of tv parts.  Maybe the actual tube number itself.  What about a tv model #.

Heh... ok I'm feeling a little stupid now but I'll swallow my pride.

Just got back from dropping into the workshop quicky, it seems that you are absoltely right. If I had even half a brain I would have picked up on it though seeing as the TV isn't even an LG. 

As it turns out its a TEAC  model no. CT-M5928TXT

Hope that helps.

Also I'm still wondering if using the relay will kill it if it is in fact a momentary style switch. Seems to me that while it probably won't work it shouldn't hurt too much.
I'm going to try it tomorrow unless someone knows its a bad idea and can save me from myself.