Testing PCB's
I finally finished all the PCB's and tested them. Mostly they worked, only one circuit needs further investigation.
I finally finished all the PCB's and tested them. Mostly they worked, only one circuit needs further investigation.
Feature |
Test and Result |
5v regulator for Fans |
Pass. Both fans together draw 100mA from 8v supply |
Battery Protection Board |
Connected Batteries to the board and got 7.2v on the output. *thumbs up* |
Battery Charging |
Connected the main PCB to the Battery PCB and plugged in the charger to its port. Nothing blew up, charger light changed to charging mode, and voltage slowly climbed |
Battery indicator LEDs |
Had to fiddle with the pot to get it right but its set at a good place. 8.2v is max, first green LED turns off at 7.8v, second green LED at 7.2, third green LED at 6.5v, at yellow turns off at like 6v. Intent is to plug it in at around 6.5v so once all greens are off you're in trouble. |
3.3v regulator |
Outputs 3.3v just fine |
N64 connected to screen |
It worked! draws about 1A from the supply at 8v. Got video and sound from the screen. |
Screen inhibit |
Does not work. the screen is always inhibited if I let the circuit do what it wants. I'll need to look deeper into this probing each of the opamp's pins with a scope. |
Killed my N64
I think I killed it by being cocky. It was 2:30AM and all my tests were passing, so I got too sure of myself and was not grounded and touched the N64 heat sink on the RAM modules and the screen went blank. Power cycle did not fix the problem. I should mention that earlier I had accidentally plugged the Jumper pack (Ram Bus) backwards so the 3.3v was shorted to ground. Took me a while to figure out what was messed up. So maybe its just that little PCB that's fried. I couldn't see any visual indication of stuff messed up. The 3.3v regulator is pretty smart and protects against over-current conditions and recovers in "hiccup" mode where it tries to bring the voltage back and cuts again if its shorted. Either way after the screen went blank it never recovered. I saw took off the heat-sink on the RAM modules (RDRAM18-NUS B) and took some heat readings with the FLIR. You can clearly see that one chip is getting way hotter than the other. I looked up the part and found other people talking about it, at the bottom of the page you can find the Datasheet for a very similar part. I used that to scope the output pins. No activity on the Data lines, and the clock was barely oscillating. So I'm pretty sure the whole board is busted. Plus I was careless and got thermal paste on the pins of the components... that stuff is conductive at 99% pure silver so shorting can occur.
I bought a new N64 on ebay for $40 including shipping. I was very happy to find something so cheap. The worst part is gonna be de-soldering stuff again and soldering the cartridge connections, those were painful. Will fix the screen inhibit circuit before I start hacking the new N64 board... provided its not dead on arrival.
I think I killed it by being cocky. It was 2:30AM and all my tests were passing, so I got too sure of myself and was not grounded and touched the N64 heat sink on the RAM modules and the screen went blank. Power cycle did not fix the problem. I should mention that earlier I had accidentally plugged the Jumper pack (Ram Bus) backwards so the 3.3v was shorted to ground. Took me a while to figure out what was messed up. So maybe its just that little PCB that's fried. I couldn't see any visual indication of stuff messed up. The 3.3v regulator is pretty smart and protects against over-current conditions and recovers in "hiccup" mode where it tries to bring the voltage back and cuts again if its shorted. Either way after the screen went blank it never recovered. I saw took off the heat-sink on the RAM modules (RDRAM18-NUS B) and took some heat readings with the FLIR. You can clearly see that one chip is getting way hotter than the other. I looked up the part and found other people talking about it, at the bottom of the page you can find the Datasheet for a very similar part. I used that to scope the output pins. No activity on the Data lines, and the clock was barely oscillating. So I'm pretty sure the whole board is busted. Plus I was careless and got thermal paste on the pins of the components... that stuff is conductive at 99% pure silver so shorting can occur.
I bought a new N64 on ebay for $40 including shipping. I was very happy to find something so cheap. The worst part is gonna be de-soldering stuff again and soldering the cartridge connections, those were painful. Will fix the screen inhibit circuit before I start hacking the new N64 board... provided its not dead on arrival.