Discuss hardware-related topics, such as development cartridges, CopyNES, PowerPak, EPROMs, or whatever.
PPU Pin 18: Not change
Last edited by jcarlos on Thu Feb 04, 2021 11:24 am, edited 2 times in total.
PPU Pin19 A: measured in DC (Not change)
Last edited by jcarlos on Thu Feb 04, 2021 11:23 am, edited 1 time in total.
PPU Pin 19 B: measured in AC
PPU Video out:
In summary, it seems that everything is the same except for pin 4 of the CPU that now does not give a signal but a kind of noise. However I have not changed anything about that part of the mainboard.
This shows a oscillation of approximately 30MHz (probably 26.6MHz) of 20mVp-p superimposed on an oscillation of approximately 4MHz (???) of 10mVp-p. That's bad. This pin (A0) should be going from roughly 0V to 4V regularly, at least every 600ns to 3µs.
Yeah, this is approximately what you should see.PIN 4 CPU before changing the PPU:
Please check what happens to CPU pin 4 immediately after you release the /RESET button.
I have reviewed the connection between CPU and PPU and there was a broken connection, between D0 (Pin 28 CPU) and D0 (Pin 2 PPU). There is already a signal on pin 4 of the CPU, a 593.8 Khz signal:
Although pin 19 of the PPU is still high, not giving a 50Hz signal. I don't know if this is normal. What I do observe is that the PPU does not get as hot as before. It may be that the signal from pin 19 of the PPU depends on the memories ?, which one is missing and the other is damaged.
It should not depend on whether the PPU RAM is damaged. It definitely does depend on the cartridge. It may or may not depend on the CPU RAM.
I have tested the mainboard with the new PPU, the two new memories and the repaired RF module and this is the image I get. A little disappointed but from seeing nothing to seeing something is already a step. What could it be? From the videos I've seen, could it be the memory of the PPU, is it new, but could it be badly welded? It is an attempt at the Super Mario Bross game.
That's awfully close to correct. Do you have another cartridge to test with?
The cartridge is fine because I have tested it on another NES and it looks perfect. Right now I only have this one, the others are at my brother's house.
I have a mainboard that works correctly and this one you can almost see. But I do not observe welding error. The bridges that I have put, due to connection cuts, seem to be correct. All compared to the good mainboard.
I'd tentatively suspect the cartridge connector at this point? Or ... maybe the 74LS373?
I have played a game and you can see the enemies and Mario jump and it can be heard perfectly. What is more deformed is the background decoration.