A very easy two solder point fix. You can use this Guide as a reference for replacing any capacitor. The capacitor replacement is needed should you have erratic or no screen display and sound. But be sure the NES game cart contacts are not the culprit first.
Identify that it is not the contacts
Be sure the NES does not have any issues with the cart contacts and or a flashing Red Light. Even if no flashing light, the contacts or game cart might be dirty. Try different game carts, clean the contacts of both the game cart and console. The console contacts can be cleaned with a long QTip or a piece of cardboard dampened not dripping with alcohol.
On my console it was obvious that the cart contacts were not at fault. A horizontal rolling grey screen and a loud buzz with a normal steady red power light. Since my NES had the 10NES Chip disabled, the rolling screen and buzz occurred even with no game cart inserted. Tapping the capacitor with a handle of a screwdriver with the power on would affect the buzz and screen roll.
CRTGAMER wrote:To discharge any stray electricity in the capacitors, unplug the NES and then press the power and reset buttons o few times.
Refer to the OP in the first page for disassembly
Taking the NES apart allows a much easier access to clean the contacts. While the console is apart, observe the capacitor located on the RF modulator. It is where the Power Supply, RF and Composite cables all plug in. Look for any corrosion or a swelled top of the crosshatch pattern on top of the capacitor. Note that a crosshatched pattern is normal as long as the top is flat. A swelled dome is a sign of a corroded capacitor.
The capacitor is in the RF Modulator at the bottom next to the RCA connectors.
Capacitors are like a rechargeable battery
Designed to temporarily hold surges and supply power, the Anode to Cathode corrosion process creates the electricity. As in any battery, the internal plates eventually corrode to the point where the capacitor will not store energy.
CRTGAMER wrote:All electronic components have a limited life due to capacitors that will fail.
Capacitor Positive and Negative location
Before removal observe the negative location. It is the lighter grey section on the insulation of the capacitor. Note that the negative side is to the left next to the aluminum rectangle.
Capacitor specs: 2200 uf / 25 Volt / 85◦ Celsius
Most electronic specialty stores sell these for around $2.00. The Voltage and Temperature rating can be higher, but not lower. The replacement might be a smaller size physically but as long as the specifications match, not an issue. Do not cut the legs until after soldering, the replacement may not align to the holes exactly.
Note the ground identified by the grey stripe, do not cut the wire legs yet!
Top capacitor is the old one with a swelled top.
- NES Capacitor 01.jpg (138.55 KiB) Viewed 24698 times
Remove the old capacitor
Remove the modulator plate on the opposite side of the exposed capacitor. It pops off with the aid of a flat screwdriver. Reference the last pic in this Reply shows the solder location. A pencil soldering iron offers the easiest and lightest control. Heat up one solder pad while pulling off the capacitor to one side. Heat up the other solder pad while pulling the capacitor off the other side. You might have to repeat a couple of times, it is important you do not force remove and damage the PCB traces.
Once the capacitor is clear use a Desolder Wick and or Sucker outlined in my WEGA Repair Guide.
Inside the RF Modulator
After removal of the solder, you should see two holes for the replacement capacitor to be inserted. Note that black is for ground. Here is why you don't want to precut the replacement capacitor legs. The width probably will not be a perfect match. The long wire legs are easily bent to match the holes.
Inside the RF Modulator, black at left is ground, RCA jacks at the bottom.
- NES Capacitor 02.jpg (219.59 KiB) Viewed 24695 times
Bend the wire legs to match the holes and insert the capacitor. It does not have to go tightly flush, but pushed in far enough to clear other components when the NES is reassembled. Just a leave a small gap between the capacitor and PCB for heat dissipation and avoiding damage from the soldering. You can bend the legs on the other side to hook the capacitor in place. Heat up both the pad with wire leg then melt a tiny bit of solder directly on the wire leg and pad, not the solder gun tip.
Observe that the solder is solid all the way around the leg and pad. Cut the excess wire leg off, be sure it is clear of the modulator cover. Pop the cover back in place and reassemble as outlined in the OP.
NES Capacitor Solder Points, two wire legs sticking out. Cut excess wire then replace Modulator cover.
- NES Capacitor 03.jpg (253.58 KiB) Viewed 24696 times
Famicom Console
The Famicom is more compact and only has a RF output connection. The RF Modulator is on a separate PCB and also has a similar capacitor that could go bad.
Look Inside a Famicom http://www.pcworld.com/article/148391/i ... nsole.html
