Famicom with AV Mod is not working
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Re: Famicom with AV Mod is not working
Yes, 10k from CPU /RESET (pin 3) to +5V (pin 40). See if the voltage does rise, and if it does rise, if pin 4 starts changing.
Re: Famicom with AV Mod is not working
But pin 4 doesn't continue to change?
Re: Famicom with AV Mod is not working
Sorry for just getting back to you, but I have limited access to an oscilloscope. With the pull-up at the reset pin I get a signal at pin4 which has a level of +3V. I could test this now. Afterwards with full euphoria I soldered the AV Mod back on and plugged in a game. After switching on I could see the game for a short time, but then more and more artifacts appeared until the game froze. Since then I can turn on the console, but I can't see the game anymore.
When I have the game plugged in, there is no data signal on pin4. Sometimes the signal is High, but most of the time it is Low. But without the game there is a data signal.
I hope that I have not destroyed the game.
Do you have more tips what I can test?
When I have the game plugged in, there is no data signal on pin4. Sometimes the signal is High, but most of the time it is Low. But without the game there is a data signal.
I hope that I have not destroyed the game.
Do you have more tips what I can test?
Re: Famicom with AV Mod is not working
I think you might have cooked your CPU when you soldered to the audio pins...
What's supposed to happen is:
* if pin 3 is high
* and pin 29 is receiving a clock
* then pin 31 will emit a clock that is 1/12 (or 1/15 or 1/16 for other regions) of pin 29
* and pin 4 will continue to toggle low/high no less often than every 5 counts of pin 31 until the CPU receives an instruction that causes it to crash. (Design flaw in the 6502)
What's supposed to happen is:
* if pin 3 is high
* and pin 29 is receiving a clock
* then pin 31 will emit a clock that is 1/12 (or 1/15 or 1/16 for other regions) of pin 29
* and pin 4 will continue to toggle low/high no less often than every 5 counts of pin 31 until the CPU receives an instruction that causes it to crash. (Design flaw in the 6502)
Re: Famicom with AV Mod is not working
I guess that doesn't sound good to me, unfortunately. Is there still hope for the Famicom board or does it look very bad now. The screen is black/green when I turn it on, just like before. Nothing has changed.lidnariq wrote: ↑Fri Feb 10, 2023 6:35 pm I think you might have cooked your CPU when you soldered to the audio pins...
What's supposed to happen is:
* if pin 3 is high
* and pin 29 is receiving a clock
* then pin 31 will emit a clock that is 1/12 (or 1/15 or 1/16 for other regions) of pin 29
* and pin 4 will continue to toggle low/high no less often than every 5 counts of pin 31 until the CPU receives an instruction that causes it to crash. (Design flaw in the 6502)
Re: Famicom with AV Mod is not working
I suspect you only damaged the CPU, so it's probably repairable... but maybe not for cheaper than another original RF Famicom.
Re: Famicom with AV Mod is not working
Are the clone CPUs on Aliexpress more expensive now?
Re: Famicom with AV Mod is not working
Ok that's a pity. Nevertheless, thank you lidnariq for your support and your help. Then I will probably have to look around for another.