Stock PSone screen backlight...

HBN · Post by **HBN** » Mon Dec 22, 2008 12:52 am

Is there a way to power the stock PSone backlight without anything but the step-up transformer?

Can I just put 7.2v into one end of the transformer (Looking at the board, it'd be the end with four wires) and have the tube light?

It might be interesting for a project, so I thought I would ask if anybody knew.

Even if nobody knows, any ideas on where I should start?

palmertech · Post by **palmertech** » Mon Dec 22, 2008 1:40 am

Why?

There are likely better ways to accomplish whatever it is.

Unless this is "just because".

Rekarp · Post by **Rekarp** » Mon Dec 22, 2008 5:09 am

The Backlight NEEDS a high voltage to energize the gas inside the tube to make it light. This is what the Transformer is for.

HBN · Post by **HBN** » Mon Dec 22, 2008 10:17 am

I realize that Rekarp. What I wasn't to do is power the transformer without powering the rest of the board. Because as you know the rest of the board is fried (This is the same backlight from the screen I blew in my SNES thread. I'm hoping I didn't fry the transformer, too).

What pins to I have to power?

And lets assume for a second that the transformer is dead, what voltage is high voltage? In case I need to juryrig something to power it. I'm adamant on using it.

Rekarp · Post by **Rekarp** » Mon Dec 22, 2008 10:20 am

I wouldn't know are there any markings on it?

HBN · Post by **HBN** » Mon Dec 22, 2008 10:30 am

Absolutely none. I'll all for experimenting with it, but... I dunno, frying it would be bad. I don't suppose people could do me a favor and check incoming/outgoing voltages on this thing for me? And then tell me which pins did what?

It'd make this project go a lot faster.

HBN · Post by **HBN** » Tue Dec 23, 2008 10:15 am

Bump. I'd test it myself, but the screen board is fried. Thus, I cant test things that have to do with power. Sure somebody has a working, un-modded PSone/Zenith screen they could test this for me with.

Please?

palmertech · Post by **palmertech** » Tue Dec 23, 2008 11:03 am

What exactly do you want to do this for, though? If the screen board is dead, why make the backlight work?

I might be able to test later, if I can find the right tools in my "Garage-pile-o-MESSY DOOM!"

HBN · Post by **HBN** » Tue Dec 23, 2008 11:17 am

palmertech wrote:What exactly do you want to do this for, though? If the screen board is dead, why make the backlight work?

I might be able to test later, if I can find the right tools in my "Garage-pile-o-MESSY DOOM!"

I said before that it would be good for a project if I can get the thing to light. Its very bright. Maybe between saying that and now I actually have a project.

I'm thinking its possible that it takes two 7.5v inputs. Hence the four wires on the input side. I dunno though.

bacteria · Post by **bacteria** » Tue Dec 23, 2008 11:27 am

If I remember, I will try and look into this for you when I tamper with the transformer in my current project - basically, I need to relocate it.

HBN · Post by **HBN** » Tue Dec 23, 2008 11:44 am

Thanks, bacteria. Please do remember.

Neildo_64 · Post by **Neildo_64** » Wed Dec 24, 2008 2:00 am

The transformers output would depend on the input. Best way is to use a multimeter, or you could unwind all the coils and count the number of wraps, blah blah and figure it up. Mad props if you do it the second way.

superdeformed · Post by **superdeformed** » Wed Dec 24, 2008 3:06 am

According to the datasheet for the screen module, the backlight takes 690Vrms, so just probing around on the transformer while it's running may not be the best idea.

Aside from that, the transformer alone is useless; if you hook up 7.5VDC to it, you'll have nothing more than an oversized resistor (so in short, the answer to your original question is no). In order to make use of it, you need an inverter circuit to turn the DC voltage into AC, which is what the top part of the board is doing. You may be able to use just this part of the board, but there are a few control signals coming from one of the main ICs. I couldn't find a datasheet for the OZ970 (the inverter controller, which also handles ignition for starting the lamp), but I did find one for a similar controller, the OZ960. Going by the OZ960 datasheet, at the very least there is an enable pin and an (analog) control pin that is used to dim the lamp. Unfortunately, from just glancing at the board it doesn't look like the pinout is the same (the would-be active high enable pin is connected through a capacitor to ground).

If you're still interested in using the transformer, the best thing to do would be have someone else probe around the inverter controller, which it looks like atleast one person has already volunteered to do (I don't have a fully working board to test). Going by the OZ960 datasheet again, the places to start would be pin 3 (3.3V active high enable, this should be constant and close to 3.3V if the backlight is on), and pin 14, which is the dimming control. If the pinout is the same, pressing the brightness buttons should change the voltage here.

edit: Scratch the pin numbers, I just realized the OZ960 is 20 pins rather than 16, that's what happens when you try and read datasheets at 4:00 in the morning

. I guess you'll either have to try and find the real datasheet for the OZ970, follow the traces out on the board, or just start probing anything that doesn't look like ground or power on the IC.

HBN · Post by **HBN** » Wed Dec 24, 2008 10:57 am

Son of a crap... that's a loaded post.

Damnit, I don't have the skill to trace a board like this. Not to mention I would get the headache from hell. I guess I have to find another light.

Anybody donating a PSone/Zenith screen board that the backlight still works but there is something wrong with it otherwise? (Wont output correct/any video to the LCD... things like that.)

Just asking...