Hello,
I am NOT responsible for any damage done to the system by taking this advice. You do this under your own free will.
If you don't have the original RF switch, get a pair of AV cables. The side of these units do accept AV inputs.
Clean the games with a solution of rubbing alcohol and very little water (depending on the percentage of alcohol used). Use a q-tip and and dip it in the solution and clean the contacts on the cartridges the best you can.
To clean the system: I will assume you do not have a cleaning kit handy, so we will compromise. That SMB/Duck Hunt cartridge is worth less than a dollar and this may not hurt it. Use the q-tip covered in rubbing alcohol and put it on the contacts of the cart. You do NOT want it dripping wet, but you do want it moist.
Insert the cartidge and press down usually half way until it hits the system's contacts. Keeping pushing it back and forth in the system; stopping to clean the cartridge's contacts again and again. Repeat this process.
The system may or may not work properly after this. Do NOT test the system while the games and system are wet from the cleaning.
This is way you clean NES systems with common items.
Kind Regards,
'mint'
PS: If this doesn't work and the system does not work, assuming it powers on, we know the power cord is good. Those are worth about $7-$10 on the open market on a good day.
These (systems) can be repaired (assuming it powers on, by replacing the system's PIN connector. The cost is usually not worth the effort. Like I said, I sell these systems wholesale with games for $29.95 and yes, that does include the light gun!
Thanks for your advice, I'll try to clean it without destroying it