per
Veteran Member
I recently bought a NTSC NES to play some of the games I have in their original speed.
So, I received the unit, and plugged it in. I turned it on, expected at least something, but nothing happened. After a quick check with a multimeter, it turned out that the fuse in the power transformator had blown.
I replaced the fuse, but still nothing. I opened the RF-box, and there I found one of the worst soldering patches I have ever seen. I removed the bad patch and verified that the diodes in the AC/DC converter worked, but it was still not showing any sign of life when I tried to power it on again. Another check turned up that now the diodes were gone too, and I decided to run DC directly through the 7805.
For some reason, it actually powered up when using DC directly on the 7805. I then tried it with our TV. I did get a picture of the game running, but the sound had quite a lot of that 50Hz AC noise in it. The picture also had lines of darker/ligther colour, which I guess is due to the same noise (or that our TV isn't compatible with NTSC, something I doubt since the colors and sync are processed right). I don't know if it's the DC-transformator or just external noise, but it sure is annoying.
In comparasion; the AC adapter for the NES usually outputs something like around 12VAC. The DC adapter I used outputs around 13VDC, but the 7805 rues it down to 5VDC anyways.
So what can I do to fix this thing? Should I just buy a new unit (may cost me up to $75), should I attempt a repair myself, or should I try to send it to an electronics expert for repair?
So, I received the unit, and plugged it in. I turned it on, expected at least something, but nothing happened. After a quick check with a multimeter, it turned out that the fuse in the power transformator had blown.
I replaced the fuse, but still nothing. I opened the RF-box, and there I found one of the worst soldering patches I have ever seen. I removed the bad patch and verified that the diodes in the AC/DC converter worked, but it was still not showing any sign of life when I tried to power it on again. Another check turned up that now the diodes were gone too, and I decided to run DC directly through the 7805.
For some reason, it actually powered up when using DC directly on the 7805. I then tried it with our TV. I did get a picture of the game running, but the sound had quite a lot of that 50Hz AC noise in it. The picture also had lines of darker/ligther colour, which I guess is due to the same noise (or that our TV isn't compatible with NTSC, something I doubt since the colors and sync are processed right). I don't know if it's the DC-transformator or just external noise, but it sure is annoying.
In comparasion; the AC adapter for the NES usually outputs something like around 12VAC. The DC adapter I used outputs around 13VDC, but the 7805 rues it down to 5VDC anyways.
So what can I do to fix this thing? Should I just buy a new unit (may cost me up to $75), should I attempt a repair myself, or should I try to send it to an electronics expert for repair?