To the best of my abilities, I'm trying to repair an Atari 800XL which was sold as "non working unit". I found a new graphics chip and it's working ok. I though that, since I had it opened up, it wouldn't be a bad idea to replace the caps, even though they didn't show any leakage. So I did, i changed all of them but 3 are still remaining. They do not have any polarity marking and I eventually learn that they are Non-Polarized Electrolytic Capacitor. The marking reads:
"Nicon 4.7 uF, 35v, NP, -40 to +85ºC"
I'm trying to find replacement for these but I can't seem to find exactly the same and, since my knowledge on the topic is very limited (no formal education in electronics whatsoever) I would need some help.
The closest thing I found are capacitors with the same range of values but marked as "Bi-Polar" instead of "NP". I don't really know if it means the same as info I found in internet is contradictory.
If anything else fail, could I replace these capacitors with non-electrolytic ones? Again, since my lack of knowledge of non of them have polarity... all seems the same through my eyes...
Any help will be appreciated.