T1 bright white LEDs

damphool · Post by **damphool** » Mon Sep 12, 2005 10:02 pm

Howdy all. I am using a PSOne screen (trying to do the chapter 13 playstation by hand). Anyway, I have had everything torn up and ready to get at it, but, I am having trouble getting the CMD204UWC LEDs required to light the PSOne screens. It seems like Digi-key & Allied Electronics corner the market on this exact part # & both are perpetually out of stock (Digi-key is still waiting on their order expected 7-29). So, does anyone know any alternative? In doing some looking, it seems that T1 means 3mm size & that is the only defined characteristic Ben lists (no voltage, amperage, etc.). So, I found the following: http://surfcomputing.com/product_info.p ... ucts_id=35 Anyone think that they would work? Other than not knowing the specs for LEDs, I am a little scared that they are only $.49. Any thoughts?

S q u e e ! · Post by **S q u e e !** » Tue Sep 13, 2005 8:43 am

Yeah, but there are better places.

Cascade Surplus is really good, and I've used them a few times. These LEDs have worked for me very well.

or, if you like the expensive route...

LEDautomotive has them, but shipping is way to much.

**EDIT**

Just so you won't ask, the difference between shaved and non-shaved is as follows:

LED BUYERS GUIDE
Light Output:

Light output is commonly mistaken for the millicandela (mcd) rating of an LED. The mcd rating only measures brightness or luminous intensity (Iv) at a single point. When talking about total light output, we have to take into account two specifications. Not only do we need to know the mcd rating, but also the spatial radiation pattern (viewing angle) because the two are directly related.

LED's with narrow viewing angles have a higher mcd rating because when you focus more light into a smaller area, the brighter that area will be, and therefore the higher the mcd rating.

For example a 4000 mcd / 30 degree LED will have about the same light output as an 8000 mcd / 15 degree LED. Or a 3000 mcd / 30 degree will have about 3 times the light output of a 3000 mcd / 10 degree LED.

When converting incandescent bulbs to LED's in cars, it is best to have the widest angle LED's with the highest mcd rating for proper light output.

Why The LED's Are Shaved

Notice in this picture the beam pattern is very tight and focused to one spot. This is a problem. The light needs to be dispersed evenly to make the dash light up correctly. Using the LED like this created hot spots. (Areas on the dash that are much brighter than the rest.)

Flattening or "shaving" the LED makes a nice clean dispersed pattern. Here's the beam pattern of the LED after it was shaved. Notice how smooth and wide the pattern is. This is what you want so your dash will be evenly lit.

To get optimal lighting on your PSone screen, use six LEDs.

damphool · Post by **damphool** » Tue Sep 13, 2005 12:50 pm

Thanks for the advice. If I use 6 LEDs as you suggest, how should I position them (the book shows 1 in eacg bottom corner & 1 in the upper right-hand corner). Also, do I need to make any changes to the resistor (10 ohms recommended) or any of the other wiring that the book suggests when changing from 3 to 6 LEDs.

S q u e e ! · Post by **S q u e e !** » Tue Sep 13, 2005 1:13 pm

Nope, you don't need to make any changes. If you do use 6, it looks as good as the cathode tube, and you should position them as such:

2 each in upper right and lower right.

1 each in upper and lower left.

Post by **Gamelver** » Tue Sep 13, 2005 1:17 pm

best of all it only consumes 120ma (typical

) of power

....which is way less than the cathode tube

....

S q u e e ! · Post by **S q u e e !** » Tue Sep 13, 2005 3:13 pm

Not with six it doesn't

Sheesh Gamelver, can't you read?

j/k

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Tue Sep 13, 2005 3:44 pm

im only using 3 with foil and a switch so i can change to the brightness mod whenever

Post by **Gamelver** » Tue Sep 13, 2005 4:15 pm

S q u e e ! wrote:Not with six it doesn't Sheesh Gamelver, can't you read?

j/k

wait.....so how much ma does the cathode tube take up? I seem to remember it being 600ma.....oh wait, you were kidding

...perhaps...you were using....sarcasm

?

Weebl · Post by **Weebl** » Tue Sep 13, 2005 5:42 pm

I'm just about to start on mine too, and I found this website: Click
They seem pretty good to me, sporting 4000 mcd and a 40 degree viewing angle. Is there anybody more technologically advanced than me who could tell me if these would be good to get?

damphool · Post by **damphool** » Tue Sep 13, 2005 5:58 pm

Sweet. That answers it. So, you advise "shaving" the LEDs as well? Anything to watch out for in the shaving (i.e. filing them too far, etc.)

S q u e e ! · Post by **S q u e e !** » Tue Sep 13, 2005 6:03 pm

No, the company shaves them for you. Unless you want to save 50 cents per LED extra, just shave it down as you see fit, but be warned: shave it too far (to the point where the metal shows through) and it will electrocute you!

Foxx373 · Post by **Foxx373** » Wed Sep 14, 2005 7:33 am

Ive shaved right down to the emitter and i have never been electrocuted by it.

S q u e e ! · Post by **S q u e e !** » Wed Sep 14, 2005 12:44 pm

Huh? I did too, and I got electrocuted! Wierd...

damphool · Post by **damphool** » Sat Sep 24, 2005 6:45 pm

I appreciate the help. I got my screen finished, and it is functioning fine, but, I am having a couple issues. I noticed that the pieces of light diffusing plastic (2 thin plastic pieces covering the lens) seem to be different on each side (one side is a little more shiny and the other a little more dull). I didn't pay attention to them when I took it apart. Which side is supposed to face up? Maybe this is related, but, even with 6 LEDs, the screen is not as bright as I expected it to be, and it has a really blue tint (I used the white LEDs suggested in a previous post). The light is evenly distributed (no hot spots), but, the blue color & the lack of brightness really have me guessing (maybe I am expecting too much). I thought about shorting the c23 (?) path on the back of the board (as Ben suggested in the book to increase the brightness), but, even with the thinest wire & smallest soldering tip I have, I don't have a prayer of getting that path shorted (it's just too small). It looks OK in the dark, and, I knew that it wouldn't be as bright as the bulb I took out, but, it still leaves much to be desired. Any thoughts?

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Sat Sep 24, 2005 7:23 pm

just put a tiny blob of solder over it to short it