n64 powers on for a few secs, then restarts...

[Deck]

I wired my n64 to an led modded ps1 screen and a battery, pretty much with harshboy's wiring diagram. I'm using a pth08000, although i'm using a 2.2k ohm resistor and a 1000 uf cap, since that's what i had on hand.

when i turn it on, it starts up, and the game runs for less than ten seconds, then the n64 just restarts. after a few restarts, it just straight up turns off. The screen always receives power, and the red light on the n64 always stays on, too. help me out!

oh, and i didn't have a fixed +8V voltage regulator, so I just used a 1N14001 diode in series with the screen to step down the voltage of my 9V battery, just to make sure that I didn't fry it.

[limpport]

The resistor should be fine, but I think the capacitor cannot hold a high enough charge to stay on long enough. The N64 restart button cuts the power on the 3.3v line (I believe), so I think the capacitor is sort of doing the same thing. Finding a 100uF cap is really your only option.

[Deck]

hmm, i thought that 1000uf has more capacity than 100uf... i'm a noob, though
also, i figured that the capacitor isn't actually necessary, but just for protection from voltage spikes, or something, since it's connected in parallel.... so i already tried just removing the thing, but the 64 continued to act the exact same way.

[timmeh87]

1000uf is a bit larger than you want but it shouldn't really be the problem.

If you are using a 9v battery instead of a 7.2 volt battery.. ... Wait, first of all, please describe your battery. Its not just a 'normal' 9v battery is it? Its not a 8-cell NiMh is it? both of those things are not ideal.

If its an 8-cell NiMh battery, then its actually 9.6v, and so its actually ~10.8v on a full charge. Using a diode is really not the best way to reduce the voltage, and you are probably going to need about four diodes in series to make it look like a 7.2 volt battery. (you meant 1N4001 right?). The diode is going ONLY to the screen right? It can only do 1 amp.

However, if your screen is turning on then it is probably not the problem. People here have had problems using a psone screen on a 9.6v battery, but if you can see a clear picture for any amount of time then it is probably working. If only the screen was acting weird then the game wouldn't keep resetting and (Im assuming this is whats happening) going through the opening credits.

My best guess is your battery is too small or not charged enough. Measure the voltage on it. If its <9v and its an 8-cell 9.6v battery, then its super dead. charge it back to 10.8. What size cells are you using? Not AA hopefully.

[Deck]

Its not just a 'normal' 9v battery is it?

...is that possible? I feel like the voltage would sag. well, no, i'm not.

Its not a 8-cell NiMh is it? both of those things are not ideal.

it's a lithium battery from a dvd battery pack. It's an add on, so i didn't actually take it out of a dvd player, though. And, of course, i checked the voltage of it fully charged before i hooked it up to anything, and it was roughly 9.3V, or close to it. Even though it's lithium, it's not 7.4 or 11.1V.

(you meant 1N4001 right?). The diode is going ONLY to the screen right? It can only do 1 amp.

yes, 1N4001. 'twas a typo. And yes, it is only going to the screen. The line on the n64 is a 12 volt line originally, so why would i reduce the voltage on that one, too?

If only the screen was acting weird then the game wouldn't keep resetting and (Im assuming this is whats happening) going through the opening credits.

yes, the screen has no problems.

My best guess is your battery is too small or not charged enough. Measure the voltage on it. If its <9v and its an 8-cell 9.6v battery, then its super dead. charge it back to 10.8. What size cells are you using? Not AA hopefully.

i doubt it's the battery. The red light on the n64 is on the 12V line, right? it always stays on: it doesn't even flicker, so i'm guessing the issue with with the 3.3V line.

[joeyjoe9876]

Its not just a 'normal' 9v battery is it?

...is that possible? I feel like the voltage would sag. well, no, i'm not.

Its not a 8-cell NiMh is it? both of those things are not ideal.

it's a lithium battery from a dvd battery pack. It's an add on, so i didn't actually take it out of a dvd player, though. And, of course, i checked the voltage of it fully charged before i hooked it up to anything, and it was roughly 9.3V, or close to it. Even though it's lithium, it's not 7.4 or 11.1V.

(you meant 1N4001 right?). The diode is going ONLY to the screen right? It can only do 1 amp.

yes, 1N4001. 'twas a typo. And yes, it is only going to the screen. The line on the n64 is a 12 volt line originally, so why would i reduce the voltage on that one, too?

If only the screen was acting weird then the game wouldn't keep resetting and (Im assuming this is whats happening) going through the opening credits.

yes, the screen has no problems.

My best guess is your battery is too small or not charged enough. Measure the voltage on it. If its <9v and its an 8-cell 9.6v battery, then its super dead. charge it back to 10.8. What size cells are you using? Not AA hopefully.

i doubt it's the battery. The red light on the n64 is on the 12V line, right? it always stays on: it doesn't even flicker, so i'm guessing the issue with with the 3.3V line.

the red light is the 3.3v line...

[killercottontail]

Try using two 1kohms resistors instead the 2.2. The actual value of the resistor should be as close to 1.89kohms as possible. Otherwise recheck all connections and replace your capacitor with a 100uf one. There should be no problem with a 9v battery (works perfectly fine in my setup). Good luck

[Deck]

the red light is the 3.3v line...

oh, i was just guessing that it was on the 12V line, i didn't really know for sure...

i guess that all i can do at this point is try a 2k resistor instead...
i just hope that it's not something wrong with the n64 mobo
if it is, i'll just buy another n64 at the thrift store for 5 dollars, i guess...

[timmeh87]

Hmmm... 9.3v... fully charged?

If that's a lithium-ion or lithium polymer battery then its broken. If it was an 11.1v battery, then that would be almost exactly the voltage it would be if it was dead. But if you say that its fully charged then something is terribly wrong.

Or else could it be a lithium phosphate battery (3.2v per cell)? It seems unlikely in a DVD player.

Are you sure its charged and that your charger works? Can you watch 10 minutes of a DVD?

[limpport]

Try using two 1kohms resistors instead the 2.2.

That's the only way I've ever done it. Give that a shot.

Also, check for shorts on the board, like if a little piece of something is connecting pins on a chip. Make sure the board is nice and clean. A soft-bristled toothbrush used lightly is the best way I've found for cleaning dust and crud from around and under an N64's chip contacts.

[Deck]

Hmmm... 9.3v... fully charged?

If that's a lithium-ion or lithium polymer battery then its broken. If it was an 11.1v battery, then that would be almost exactly the voltage it would be if it was dead. But if you say that its fully charged then something is terribly wrong.

Or else could it be a lithium phosphate battery (3.2v per cell)? It seems unlikely in a DVD player.

Are you sure its charged and that your charger works? Can you watch 10 minutes of a DVD?

i dunno, man. i bought it brand new for this project, so i haven't used it to actually power a portable dvd player. There is a "fuel gauge" on the side of it made of a line of 4 leds. it was empty when i bought it. I charged it for a while, and now it's not empty. It claims to be a lithium battery, and it claims to put out 9V. if it's broken, then It's a defect.

[killercottontail]

Is your battery a Coby BP-420? That's the battery I'm using and it works great. It has the same setup (li-ion, fuel gauge, 9v). It actually puts out less that 9v (around 8.2) but it works totally fine. Like I suggested use 2 1kOhms resistors instead of a 2.2 and hopefully you'll get better results. If not it's definitely something wrong with your mobo.... A battery with these specs should take around 5-6 hours to charge at least btw.

[Deck]

yea, i copied you with the coby bp-420
and, yes, i went to radioshack today to buy some 1k resistors, and it seems to have fixed the problem, even with the 1000uf capacitor.

thanks for the help.

on the topic of the coby bp-420, did you take it apart, or just use the whole unit? seems tough to dismantle...

edit: nevermind, i'ma take it apart, anyway. There's a lot of empty space in it

[killercottontail]

There's tons of extra space inside lol. Just pry or dremel it open starting at the back and work around to the front. Just be patient so you dont snap the leds or something.

[timmeh87]

That is most interesting...

If it was a lithium phosphate battery, I would buy that story.. Or maybe it has an internal dc-dc converter? Like its one giant cell with a step-up converter? I looked up what this thing is, and that seems likely. Do you have pictures of the inside?

9.3v = 3.1v per cell charged, 8.4v = 2.8v/cell while operating. That doesn't sound like any real kind of lithium battery. Unless the output voltage has no clear relationship to the voltage per cell because there's some kind of regulator.

In that case you might want to see what kind of battery you /really/ have by opening it. maybe there's a 7.2v battery in there.