Straighten me out..

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Okay, guys, I need someone to correct me on some things.

After months and months of reading, I’m about two weeks away from beginning building (waiting of the tax return for funding.) I’m trying to nail down as much of my design before I get started as I can.
I was given a 17” LCD with backlight problems, so that part is handled. But my lens is the 80mm triplet from DIYPC and I understand that it won’t cover the entire screen. My plan is to shrink the image down using the monitor controls to a 15” image. This should work just fine, right? Has anyone else done this? Will I need to block (with tape or something) the unused edge of the screen?

The only reason I ask is because the monitor needs a $50 power adapter and I can pick up a new 15” lcd monitor for $150. If this plan isn’t going to work, I might as well just buy the new monitor.


Also, the fresnells need to cover the entire LCD, right? So will I need to only cover the 15” image, or the entire thing? I see people using the page magnifiers, but I’m guessing they’re really only good for PS.one projectors?
 
well if you got a free 17" and it stripps easy i would iether use a app called power strip to adjust yer screen size or just get a 18-22" beseler lens that go for around $75 .....but if you do go and shrink the screen then youre fresnel only needs to cover the 15" part with the image on it. by the way what is the brand and model number of you lcd ?
 
It's an HP F1703
This was my first time stripping a monitor and I had no problems whatsoever.
The specs on it aren't great, but I couldn't beat the price.

I just realized you might be talking about the 15" for $150.
That can be found here:

http://www.walmart.com/catalog/product.do?product_id=3300986

I would consider dropping the extra on another lens, but the one I have I got for another good deal... There's a pattern here, I know.

And I'm cheap, so that doesn't help...😀
 
i am also very cheap lol did the monitor need a ffc extension ?
if i were you i would get biggest fresnels you can find and for the 17" lcd and use the lens you have now so yer only out money for the power supply ... unles you make one for it ... and the fresnels when you get it all hooked up see how much of the screen can be seen then adjust yer image with iether the powerstrip program and/or just resize the player itself to fit see how you like it. oh what light source you useing ?
 
No. The LCD connected to the board with wires, no ribbon cable.
I'm going to use the same MH bulb and cheap HPS ballast everyone else seems to....I can't seem to find anything cheaper.

(ALthough I am tempted to gut an old halogen floor lamp...):devilr:
 
This issue has been driving me nuts since I got the LCD. The power adapter needed has the following specs (per the HP website)

Input rating: 100-240 V, 2 A maximum
Output rating: 12 V, 3.75 A
Frequency: 50/60 Hz
Power consumption: Less than 50 W in operating mode

I've found various adapters, but they all seem to be too low in the wattage department. I'm not even sure the $50 will do the job, but a local computer store seems to think they have one that will do the job at 50 bucks. I still need to take the monitor in there and see if it will work. If it doesn't, I'll probably end up buying the $150 monitor and going with that instead.

I would love to hear of other ideas for power supplies, if anyone has any.
 
I would power that monitor with a cheap computer power supply. Even a very modest 250w or 300w model will be more than sufficient. If you don't have a spare or obsolete computer laying around you can get a power supply at your local computer store. It shouldn't cost more than about $20. As an added bonus, you can also use the power supply to run fans, necessary for cooling the LCD and light engine.
 
Actually, I think I have about 3 of them laying around.
(BTW: good to see someone else from this area on here.)

The problem is, the power adapter looks something like this:
An externally hosted image should be here but it was not working when we last tested it.


And I would have no idea how to go about wiring my computer power supply up to the monitor....
(Hell, I didn't even think that would be possible. Electronics are not my forte)

If it's possible, I love the idea....
 
The source wires to use a PC power supply (ps) to run the monitor are found on the 4 pin molex connectors. There are 4 wires, a yellow one on one side, a pair of black ones in the middle and a red one on the other side. The yellow wire is +12v, both black wires are grounds, and the red is +5v. So you need the yellow and one of the grounds.

Now about connecting those wires to the monitor. It could be done 2 ways. The best option (what I would do) is to connect them to the monitor's power circuit after the round power jack (that the regular power supply would plug into). This will probably require delicate soldering, but it eliminates that round power connection entirely.

The alternate method would be to take any old power adapter that has the right size round plug on the end that fits the monitor's jack, and cut off the end leaving a few inches of wire to work with. Then you can splice that end onto your yellow & black wires out of the power supply. You'd have to solder using this method too, but it would be easier. I don't like this as much because you've potentially got a few inches of smaller guage wire in the circuit, and the extra connection at the round jack.

If you go the ps route, be sure to keep the ground connected to ground, and the hot to the hot. Bad things would happen if you reversed the circuit 🙂
 
doublejack,
I'm going to give the computer power supply a shot this weekend. There's a few things I was wondering about, though:

I assume we're talking about an ATX power supply, with the 4 prong chip power cable. I was doing some looking around, and my understanding is that in order to start power, you have to go through the logic circuits of a mother board. I did find this:
While we're at it, you can power up an ATX power supply by shorting the green wire with any black ground wire. As you know, the ATX power supply will not turn on normally without a motherboard connected to it. There are times when you may want to test an ATX power supply or use the voltage from one but don't really want to hook up a motherboard. There's only one green wire and there are plenty of ground wires so it's easy to do. To use a bent paper clip and insert one end in the green wire connector and bend it around and put it into a black wire connector.

I'm assuming I can just wire a switch in place of the paperclip?
 
Yes, you can wire a switch in to turn an ATX style power supply on & off as described.

About the molex connector, I was actually referring to the ones that plug into drives - hard drive, CD-ROM, etc. Those 4 pin connectors are called a molex, and the smaller ones (for 3.5" floppy drives) are called mini-molex. But that extra power connection that some motherboards require (it's basically like half the old AT style power connector) would also work as a source too.

When it comes down to it, inside that power supply there are different "rails". A 12v one, a 5v one, a 3.3v one and then some negative voltage rails. All 12v wires coming out of the power supply all come from the 12v rail. So you can use any 12v wire that's convenient for you.
 
Something else just occured to me (yeah, I know; I'm just full of questions...)

When I cut the old power supply, I'm going to end up with two wires. Does it matter which one goes to the ground? I'm guessing those won't be color coded in any way (or will they?)

(BTW: if this works, you will officially be my new hero...)
😀
 
That's a good question. And yup, it does matter how you connect those. If there are no indicators to tell you which wire is the ground then you may need a multimeter to figure that out. If you don't have access to a multi meter there are other ways too, maybe use a test light or a simple / cheap device that operates on 12v to figure out the polarity.
 
When I cut my computer power cable, I tested it with a continuity tester. I just connected one end of it to the ground plug that would normally go into the ground outlet, and then tested each wire with the continuity tester's other prong. As soon as the light in the tester lights, you know that's your ground. You can do the same for the hot and return wires as well.
 
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