Just tested a video mod, which worked perfectly. now I have removed it and tried booting like normal. Press Power, no light, no video, audio is humming noise. What's wrong?
A short somewhere? That would tend to drag the power down and reveal the ripple of the input AC. Check voltage into and out of the 5V regulator on the heat sink.
Tested with 5v direct to the board. Works. How easy is it to kill the RF block?
Multimeter shows only 2.42v across the +5v in to the board. Hmm. Dead RF box?
Did I kill the regulator by connecting a bypass video circuit?
Also seems like the RF, CPU and ppu are warm, not hot when its left running (power sw on though no light)
What's the voltage into the regulator? Look for visible shorts around the regulator and RF box, and inside it if your mod was there. You could also take high-res pictures and post.
Not sure how to test power into it. I have a 2nd project NES that no longer has an RF box and it aso heats up the ppu and CPU. I'm thinking I managed to brick them both :-/
The 7805 regulator has three pins. Looking at the front, the left pin is the input, center ground, and right output. What's the voltage between the left and center pins (can also use the heat sink as ground)?
I will check when I get home tonight. What about the other one, the one with the RF already removed?
blargg wrote:
The 7805 regulator has three pins. Looking at the front, the left pin is the input, center ground, and right output. What's the voltage between the left and center pins (can also use the heat sink as ground)?
Aren't you supposed to test from the output pin as opposed to the input?
If you want to see whether the regulator is working, you need to find the input and output voltages and see whether the regulator is getting enough voltage and whether it's outputting the proper voltage. If you only test the output and it's too low, you can't tell whether it's the regulator or insufficient input voltage (e.g. 0V output would occur if NES wasn't plugged in the wall).
pemdawg wrote:
Not sure how to test power into it. I have a 2nd project NES that no longer has an RF box and it aso heats up the ppu and CPU. I'm thinking I managed to brick them both :-/
It's pretty normal for them to warm/heat up from normal use. If its too hot to hold your finger to them you've probably got issues...