Building my N64p

[usbcd36]

Ok, done with the mod, it looks even better than the cathode tube did! There were 6 LEDs used, they are 7,000mcd and have a 30° viewing angle. I have some pics for later, but at the moment I am taking a break after successfully soldering the RGB wires to the chroma chip on the N64. Instead of ribbon cable, I decided to use something I had on hand: old Cat-5 cable. There are 8 wires inside, and it is somewhat more compact than ribbon cable at the moment. The cable I cut for the system to screen connections is too long right now, but for test purposes, I want to be able to move stuff around.

Edit: The unfortunate thing about this whole deal is that the good luck I had with the LED mod seems to have been used up. I am having trouble with the RGB, every time I solder a wire to the chip, another one comes off. Every time I test the N64 to make sure I haven't fried anything, the composite signal is missing another color (naturally, I have only tested it twice). The chip has been botched pretty badly, though it still seems to work. I know for a fact that the red and green pins are no longer soldered to the board. The blue pin doesn't seem to want to accept solder either, nothing will stick to it, and I am running out of solder. For tonight, I think I am done, I'll pick up a desoldering braid and some more solder (out of that too) tomorrow. I don't think my fingers can take any more burning from the iron for the time being.

[G-force]

Did you try using flux on the pins?

Hmm...With 6 7000mcd LED's are you really saving that much power?

Anyways good luck with it

[usbcd36]

I'll check the consumption later, right now, my legs are too tired. I'm sure it saves at least 500mA though.

Edit: It takes 499mA to run now! Also, I am having a few problems, RGB is about impossible to acquire now and to add to that, composite only comes through as blue! I'm at my wit's end, someone help me!

[Xorealix]

Ok, ditching my idea of the 3 regulators, how well would a LM317T adjustable (yes, it is 1.5A) work? The range it has includes 3.3v, but how do you wire it for that?

Okay, I'm starting to build a portable N64 and I'm running into this problem too. I finally figured out how to hook up the LM317T, but I've seen two diagrams with different R1 values.


(Thanks to nos_slived for the diagram)

The other diagram from the specs pdf says to use 240 ohms. Here's the calculations for both:

Code: Select all

3.3V = 1.25 + R2(1.25 / 470)
R2 = 770.8

3.3V = 1.25 + R2(1.25 / 240)
R2 = 393.6

Which one should I use? Can somebody please explain what difference it will make?

Also, I've seen another diagram (posted here by Electric Rain) that uses capacitors... are those necessary?

Thanks for any help. Good luck with your portable, usbcd36!

[daguuy]

the caps probably aren't necessary but probably clean it up a bit

[usbcd36]

Thanks! Now I don't have to buy that other regulator from Digikey! I think it will have enough amps, it says 1.5 and that is about the max for an N64. I am still interested in having it save power, can I use a DC-DC convertor to lower the voltage to 5v and then use the regulator?

[G-force]

That would really not be worth the money or trouble since the 12V line only uses 100ma (or less).
EDIT: Wait...you were talking about the 3.3V line Oops, I misread it. That is really not a bad idea.

I have an idea that I want to try myself. If you really want to be efficient, run the 3.3V line off 3 seperate AA's (it can run up to 4V no problem), and then power the screen and 12V lin off 6 seperate AA's. 9 AA's total.

[usbcd36]

Nice idea and all, but I'm planning to use the Ni-MH 7.2v pack from RadioShack. I don't like center tapping batteries (ie, if you used AAs and tapped at a point between batteries, those being used twice would get drained a LOT faster than the others.

[Xorealix]

Thanks! Now I don't have to buy that other regulator from Digikey! I think it will have enough amps, it says 1.5 and that is about the max for an N64. I am still interested in having it save power, can I use a DC-DC convertor to lower the voltage to 5v and then use the regulator?

Yes, 1.5 amps will be enough. I don't see why you can't lower the voltage to 5v- the spec sheet said that the Vout - Vin must be > 1.5V, so 5 - 3.3 = 1.7V. You're good to go.

Just curious, why would you use a DC-DC convertor instead of a 7805? I'm still getting used to all of these concepts. Also, does anybody know about which ohm value to use for R1 (the top most resistor)?

Note to anybody buying a PSOne screen from ebgames.com: Use code PPLAY15 to get 15% off the screen! It's only $25.49 with that code!

[usbcd36]

I would use a DC-DC convertor instead of a 7805 because a 7805 releases energy as heat (it changes the voltage, but keeps the amperage the same, therefore changing the wattage) whereas a DC-DC convertor lowers the voltage, but upps the amperage, therefore it doesn't change the wattage. In laymans terms, it makes the batteries last longer.

[Xorealix]

I would use a DC-DC convertor instead of a 7805 because a 7805 releases energy as heat (it changes the voltage, but keeps the amperage the same, therefore changing the wattage) whereas a DC-DC convertor lowers the voltage, but upps the amperage, therefore it doesn't change the wattage. In laymans terms, it makes the batteries last longer.

Ahh, interesting. Thanks for the info.

Edit: Does anybody know if I need 1/2 watt components or 1/4 watt? Should have asked before I bought the parts, but oh well. I bought the 1/2 watt resistors.

[usbcd36]

For an LED mod, you're better off with 1/2 watt because they will generate less heat.

Also, an update! I stated above that RGB was dead and composite was only blue, this has been repaired! By soldering a 2 wires from the chroma decoder chip to the holes on the bottom of the board (used in a 2-sided board for electrical contact from one side to another), I was able to bypass the traces I had destroyed earlier while trying to get RGB from the N64. There is now full, beautiful color and there will soon be RGB outputs on the N64 as well!

[Turbo Tax 1.0]

usbcd36 i know i saw pics of your led modded screen and a small how to, somewhere but cant seem to find it do you remember were you posted it

[usbcd36]

No, but I found it:http://benheck.com/phpBB/viewtopic.php?p=75844#75844.

[Turbo Tax 1.0]

thanks i think i may try just using four and using some aluminum foil like gamelver, anybody know if i need a different resistor or can i use a 22ohm