Blank Screen; what's broken?! [Famicom RF]

Started by urufuNoFamicom, February 08, 2019, 06:09:51 am

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80sFREAK

Yes, variable ceramic capacitor should work.
I don't buy, sell or trade at moment.
But my question is how hackers at that time were able to hack those games?(c)krzy

urufuNoFamicom

February 25, 2019, 02:29:26 am #16 Last Edit: February 25, 2019, 02:39:27 am by urufuNoFamicom
Wait, so does it have to be a "variable" capacitor by name? Digikey has separate selections for those. And if I'm not mistaken in reading the datasheet for the linked capacitor, it can only go on ±10%, which 1.1*22 (or 22 + 10%) is 24.2pF. Is the max being 27pF a requirement?

I found a replacement trimmer but it was like $4 :-X

Sorry if i sound like I don't know what I'm doing. My knowledge is usually project oriented, so it wildly varies based on what I'm dealing with. Just need to make sure I order the right part.

80sFREAK

Do you have any scrap electronics around? Those cheap chinese made radio or tv or whatever with thru-hole components? Get just ceramic capacitor 22pF or 27pF and replace trimmer. K.I.S.S.
I don't buy, sell or trade at moment.
But my question is how hackers at that time were able to hack those games?(c)krzy

urufuNoFamicom

No, but you [inadvertently] answered my question anyways; the 22pF ceramic will do. I'll post whether the capacitor was the issue, as well as the SRAM if the capacitor swap fails to fix it.

80sFREAK

You also might need to desolder XTAL(grey thermoshrink with 21.477 on it) and clean under and its bottom, where is pins. My guess, there is just no CLK, so everything is dead
I don't buy, sell or trade at moment.
But my question is how hackers at that time were able to hack those games?(c)krzy

urufuNoFamicom

I'll try that when I replace the capacitor. Going to hold off on the SRAM until i know for sure whether it's an issue, but i bought one just in case. Parts should arrive Friday if they ship on time. :)