Hong Kong Famicom with AV Mod - Dead :(

Started by populated, October 22, 2013, 11:27:14 am

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Pikkon

Put the transistor back in,the famicom will not at all with out it and then lift or cut pin 21 and try again to see if you get any video.

aha2940

Quote from: Pikkon on November 11, 2013, 12:56:37 pm
Put the transistor back in,the famicom will not at all with out it and then lift or cut pin 21 and try again to see if you get any video.

In fact the famicom will work without the transistor. It won't output image via RF, but the CPU will output sound and the PPU will output picture so it's a good test to know if it works.

populous: to test your famicom, you can test two things: one is the input voltage on the CPU and PPU. If they are right, check with an oscilloscope for clock signal on pin 29: http://wiki.nesdev.com/w/index.php/CPU_pin_out_and_signal_description

Regards.

P.S: If you cannot get it to work, some of the chips might be bad. They are not hard to get, but are hard to replace.

inabityo

Quote from: populated on October 23, 2013, 02:14:44 amI see what your saying, whoever did the mod back in the day could have been a bit 'chop-happy' when modding the board and sliced through some things.  These were probably jumpered originally to repair the issue.

Now I need to find a hi-res image of the same revision PCB so I can check and see whats missing or not connected.

Are there any test points on the Famicom PCB itself I can meter to confirm the Famicom is working or not?

I assume you gave up on this long ago. I have the same board. Wired completely differently! Let me know if you still need this.