Hey there, just a hardware question I came across recently. I had some recent troubles modding some Famicom Classics (old classic red & white version with permanent controllers) to AV and RGB and some had weird troubles like completely wrong colors, garbage on video signal etc. I just realized that some issues might be related to that green potentiometer on the console perhaps?? When I insert a screwdriver inside while the console is on, I can see that it sometimes turns off or resets or crashes the game but at the same time I noticed some color hue change. This is the green thing that is in the center of the photo:
Can anyone clarify what it does and what issues it can cause when faulty?? I could also see some soldering marks on some of the consoles so it looks like someone else replaced it (probably Nintendo customer service) after the consoles were produced. Please for replies, thanks in advance
The part in question is a Trimmer Capacitor.
It does almost the same as a potentiometer, except instead of a variable resistence it's a variable capacitance.
This is used to fine tune the main clock generator. Where is exactly the place this componnent is located.
A problem in this component can make the master clock do some weird oscilations.
The screwdriver induces electromagnetic interference, also causing unexpected things to happen, most of the time crashing the system.
If it is really related to the trimmer: And if using metal screwdrivers doesn't work well: You could try using plastic screwdrivers (eg. search for Anti-Static Trimmers, or use a knive and carve something similar from a piece of plastic).
But I am not too sure if the trimmers are the problem - or is that a common thing, to see misaligned trimmers in several consoles?
This thread https://forums.nesdev.com/viewtopic.php?f=9&t=10471 doesn't sound as if it the trimmer would be the #1 source of problems.
The only time I saw a bad trimmer was when I tried to save a "flooded" NES.
The console was under the water when the river flooded a friend's house for about a week.
That NES never worked again. I tried to use some parts and discovered that the trimmer was bad.
It was very rusty!!
