Some more news!!
First, I tried to socket the WRAM and have the same results.
Even with 3 different SRAM chips
Them, I tried to build another clock generator and substitute the actual one.
I ended like this:
At first it seemed to be the deal, I was playing Crisis Force and everything was smooth.
Them the game froze for about a second, but continued. Weird!!
But when I arrived at the part near the 1st boss where the floor opens, it crashed!
I tried Megaman 2, and got he same Crashman's crash. Gradius was the same thing too.
So, with no other ideas, I just tried an original NES CPU I have from that flooded NES.
Intestingly, the games worked flawslessly!! Only Gradius is still giving me trouble.
By the logic, the problem would be on the clone's CPU.
I tested it on the other clone and again, it worked flawlessly! This time even Gradius worked fine.
Taking a better look at Gradius' board, after supposing it was some kind of protection related to the diodes that some of original famicom boards use without success, I noticed the the 74'161 pin 3 is with a steady voltage of 0.8V on the Phantom System, while in the other clone the same pin gets a voltage of around 4,5 volts.
I think this means that D0 is getting pulled to the logical level 0 on the Phantom System, while in the other clone it's floating, as it should in normal operation.
I tried some pullups on this pin and all that I could get was a non working game, that was cured as soon as I removed the resistor.
Could this possibly be ralated to a bus conflict?
Interstingly, there's an empty space on the board wich ressembles a 14pin IC and is like this:
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CPU R/W--O O
PRG /CE--O O
The PRG /CE pin comes from the PRG epoxy ROM and is bridged to /ROMSEL. The other pins (including /ROMSEL) come from the cartrige edge connector.
I just could not imagine what IC should be put in there to possibly avoid bus conflicts, any suggestions?
Looks like I should try to cut the PRG ROM's /OE and add an inverter to R/W on it. Could this possibly solve the problem?
I just don't understand why this happens with an clone and not with another.
I thing this is really weird!! How come this stuff have trouble just like this!!?
I really hope that someone that is reading this can help me to throw some light on it, at least the Gradius problem...
Anyway, the problems are almost all solved! And I sincerelly hope that this discussion can be useful to someone else in the future.
Sorry for this big wall of text...
Thanks in advance.
Pictures of the Gradius' PCB.
Unfortunatelly it's not mine, but it's the same model.
Mine is without the transistors and resistors, I added 2 diodes and is a lot more wornout.