dead psone screen?

Ari · Post by **Ari** » Mon Oct 09, 2006 2:19 pm

I just picked up a psone screen at a used game store, hoping to make a portable genisis. So I opened it up and then decided to test if it worked or not. I plugged the a/v jack directly into the back of my PS2, and used the power adapter from my genisis. When I turned the PS2 on, the CCFL flashed on and then off, a spark came off of one of the transformer leads, and nothing came up on the screen. But the sound worked fine.

Then I decided to do some research into the psone screen, and realized that the max power it would take is 9v. The genisis wall adapter is 10v, and I suddenly realized just what an idiot I am. Then, thinking that the fuse was blown, I put a gob of solder over the fuse at PS1, and then used the game gear's power supply, which was 9v. The exact same thing happened.

Then after that, I decided that maybe the ribbon connector for the LCD wasn't in right, as I had taken it out and put it back in. So I made sure that was in right, and still the same thing happened. The CCFL flashed on and off, and I had audio but no video.

So, what could the problem be? Is the LCD bad? The CCFL? Maybe the transformer? Could it be fixed? Thanks in advance for any help, I'd really appreciate it.

Website · Post by **Life of Brian** » Mon Oct 09, 2006 3:01 pm

Hmm, still sounds like it's not getting the correct power. Do you have a multimeter to test what you're putting into the system? Sometimes an adapter is rated as something but gives you more... If all else fails rig something up with some fresh AA batteries - that way you KNOW you're getting the right voltage.

Post by **marshallh** » Mon Oct 09, 2006 3:02 pm

Wall warts aren't the voltage they're rated at. See, under no load (if you just hooked it up to your multimeter) it would probably read 16-17v. If you draw the amount of current it has on its label, the output voltage usually drops to somewhere around what it says.

You probably put a lot more than 9v into your screen.
What do you mean by "transformer leads"? Did you have the screen casing off, or are you talking about the wall wart's leads?

In any case, 9v is the voltage that the PSone screen goes nuts. Why? Everything on the board is powered by two 7805 regulators. Except for one crucial part: the chroma decoder. This part is supposed to run off 7.5v.

Basically, when you put in 9+v into the screen, the chroma decoder might have been zapped because it runs straight off the input voltage, no regulation (except for a few capacitors.)

If you've already tried it with the fuse jumped, you may have killed your screen. The only way I can think of to test it, is to get a 7.5v playstation one power supply and try it with that.

Also, the transformer is probably dead. There a quite a few screens on ebay which have dead transformers. You'll need to LED mod it (google on extremetech for a guide)
You can take the LCD out of the white lightbox, according to the modding guide, and hold it up to light while it's turned on. If it works, you should at least be able to press the volume buttons and get a green bar.

Post by **bicostp** » Mon Oct 09, 2006 3:04 pm

9v is about the maximum those things can take.

You may have fried the screen (especially after you jumped the fuse), but I have another theory. Maybe the power supplies you used couldn't supply the amperage the PSone screen requires (I think you need to have a power supply rated for at least an amp). If you have one, try a real PSone power supply (which can handle 2 amps), or the PSone/screen power supply (I think the screen came with a different one, which could give 3 amps. I could be mistaken...)

Thinking about it, that might very well be the case. Look really closely at the screen, maybe aim a flashlight at it. Sounds to me like the inverter for the cathrode tube isn't getting enough power to run (which would explain why you're getting sound). You might be able to see the game running on the screen. (Pick a scene with a lot of contrast, like the "THX" calibration on a DVD or the PS2 BIOS memory card manager. You never know until you try!

Ari · Post by **Ari** » Mon Oct 09, 2006 3:28 pm

I tried wiring it up to 5 AAs, but that didn't work. However, I have no idea what voltage they're really putting out. Unfortunately, I don't have a multimeter to test anything with (well, I do, but I lost it). I think I'll try a 9 volt and see if that works.

If the screen was fried, wouldn't the speakers be fried too? Or is the lcd and such more sensitive than the speakers?

EDIT: Apparantly, the 30 year old multimeter I had laying around still works. I just had to take out the old, leaky, NiCd AAs and put in some new batteries. It turns out that the genisis wall wart had ~12.7 volts... and the gamegear wall wart had a whopping ~16.8 volts. Yikes.

Oh, and the AAs I thought I had wired in series weren't even connected, apparantly. So I need to fix the connections on those, and maybe I can get something to work.

And thanks for the replies, guys! I never would have thought of any of this stuff.

Website · Post by **Life of Brian** » Mon Oct 09, 2006 4:16 pm

No prob

Ari · Post by **Ari** » Mon Oct 09, 2006 5:00 pm

Okay, I found a pack of brand new AAs and wired 5 of them together in series. The multimeter said 7.46 volts, so the power was pretty much spot on. I connected the batteries to the screen... and it got really hot and started smoldering. Turns out I had the polarity reversed. So I fixed the polarity and wired it back up. After I turned on my PS2 the exact same thing happened (the CCFL flashing, and sound but no video. So the preblem couldn't have been the wall warts.

I'm starting to think it was like this when I got it...