1993 Super Nintendo Entertainment System (SNES) Restoration & Modifications

I recently bought my first Super Nintendo Entertainment System from a vintage toys and games market in Houghton-Le-Spring, as I’d been after one for a while.

The Super Nintendo Entertainment System (SNES) is a 16-bit home video game console developed by Nintendo, following the Nintendo Entertainment System (NES). The console introduced advanced graphics and sound capabilities compared with other systems at the time, like the Sega Genesis. It was designed to accommodate the ongoing development of a variety of enhancement chips integrated into game cartridges to be more competitive into the next generation.

SNESs aren’t particularly rare, and you can pick them up in non-working condition for fairly cheap – they go for quite a bit when refurbished and modified, though. Their nostalgia value and interesting game library make them quite collectible.

It was sold as working, and it seemed to be in reasonable physical condition. I powered it up using the new PSU that it was sold with, connected to a TV using a composite video cable and with a game cartridge installed, and sure enough it worked fine.

I wanted to clean the console up and perform some preventative maintenance.

The first step was to disassemble the unit and check over everything inside.

Disassembling the SNES

The NES is easy to dismantle with basic tools: remove the six 4.5mm Gamebit screws around the perimeter of the underside of the case.

With the case opened, you get your first look inside the console – everything seemed to be original and pretty much untouched.

The eject mechanism is held in place with a spring; the power switch is held in place with two Philips screws, and unplugs from the mainboard; the front I/O panel is connected to the mainboard via a ribbon cable, which can be gently pulled out; the lower RF shield is held in place by four Philips screws; the mainboard is held in place by five Philips screws, and should then simply lift out of the lower case.

The 7805 regulator heatsink is held in place by one Philips screw on the regulator itself, and three Philips screws around its perimeter on the mainboard – with this removed, the full mainboard is now properly in view.

Mainboard Servicing

As I mentioned before, I wanted to do some preventative maintenance and practicality upgrades on the mainboard, including:

• Replacing all of the aluminium electrolytic capacitors.
• Replacing the original 7805 linear voltage regulator.
• Replacing the original single-use fuse with a self-recovering polyfuse.

Electrolytic Capacitor Replacement

Aluminium electrolytic capacitors are commonly used for filtering, smoothing, and decoupling in both high- and low-voltage electronics. They are quite cheap in comparison to their solid-electrolyte counterparts (such as tantalum and polymer electrolytics), so are very common in consumer electronics.

Their useful lifetime is highly dependent on the specific application that they are used in (i.e. frequency, ripple current) and temperature, as well as the manufacturer and series of the specific component. They typically comprise aluminium windings which are coated with a liquid electrolyte, which can dry out over time (negatively affecting the performance of the capacitor, often causing them to fail dead-short), or even leak out and cause corrosion to the PCB and surrounding components.

SMD aluminium electrolytic capacitors are common, well-documented failure points in other pieces of equipment from the 1990s (i.e. Amiga 600, Amiga 1200, Apple PowerBooks, Apple Macintosh Classic / Classic II / SE / SE/30, etc). Earlier “2CHIP” mainboards like this one are known to have leaky SMD electrolytic capacitors, whereas later “1CHIP” mainboards are perhaps less prone – these have a single ASIC known as the S-CPUN in place of the three major ICs (CPU, PPU1, and PPU2), and are supposed to have superior video quality.

There are several production variants of the SNES mainboard, each of which have different electrolytic capacitor values and locations, so take note of which you have.

The SNES mainboard is fairly easy to recap as it only has nine SMD and one through-hole electrolytic capacitor, as follows:

• C59: 10uF 25V SMD bipolar
• C60: 10uF 50V SMD
• C61: 10uF 50V SMD
• C62: 2.2uF 50V SMD
• C63: 33uF 25V SMD
• C64: 33uF 25V SMD
• C65: 10uF 50V SMD
• C66: 10uF 50V SMD
• C67: 2200uF 25V radial
• C73: 47uF 16V SMD

You can usually buy capacitor packs for these machines from sellers such as Console5, but I just made up my own by noting the specifications of all of the electrolytic capacitors on the board, and ordering a set of high-quality known-brand parts.

I decided to use tantalum electrolytic capacitors, an equivalent to aluminium electrolytic capacitors – these use a solid electrolyte, meaning that they will not physically leak.

When substituting electrolytic capacitors, the capacitance needs to be the same, and the voltage rating can be the same or higher (within reason) – when you’re going through all this effort to recap something, be sure to use high-quality replacements.

For SMD capacitors, I usually remove all of them at once using a hot air rework station with kapton tape and aluminium foil to protect the surrounding areas, or by carefully twisting them off using needle-nose pliers (this technique may not be suitable if the pads are damaged, as they could delaminate from the board – and push downwards, don’t pull upwards!). The pads can then be cleaned up using new solder and either desoldering braid or a desoldering station. The board should then be thoroughly cleaned to remove any leaked electrolyte and leftover flux, using isopropyl alcohol and an ESD-safe brush.

As for through-hole capacitors, I usually remove each one-by-one using my desoldering station, then immediately install its replacement part – this minimises the likelihood of getting it wrong. The board should then be thoroughly cleaned to remove any leaked electrolyte and leftover flux, using isopropyl alcohol and an ESD-safe brush.

When fitting new electrolytic capacitors, you must take care to ensure that the value, voltage rating, and orientation of the new capacitor are correct – electrolytic capacitors are polarised, so must be installed the correct way around, else they’ll get hot when powered on (and probably explode). The polarity is marked on the case: for aluminium electrolytic capacitors, the negative side is usually shown by a white stripe (for through-hole) or a black bar (for SMD); for tantalum capacitors, the positive side is usually shown by an orange or white bar (for SMD). This catches a lot of people out!

You can’t always trust the orientation markings on the PCB silkscreen (if it even has them, not all boards do), as sometimes mistakes were made in the design from the factory (take the PCB layout of the audio circuit on the Commodore CD32, for example), so care must be taken to match the orientation of the new capacitor with the original. Make sure to take lots of “before” pictures for reference, and double-check throughout.

Voltage Regulator Replacement

The original 7805 linear voltage regulator (5V @ 1.5A) is quite inefficient and produces a lot of heat, hence it needs a large heatsink – I decided to replace this with a modern switch-mode equivalent, the TSR-1-2450, which is far more efficient and runs cool. This is a pin-compatible replacement, so this upgrade is as simple as desoldering the original part, and soldering the new part in its place.

Fuse Replacement

The SNES has an onboard 1.5A picofuse to protect the power supply, which can often be found open-circuit – these are single-use fuses meaning that they have to be desoldered and replaced if they fail. As such, I decided to fit a 1.6A 60V self-recovering PTC polyfuse in its place, which can recover from a fault condition after it has cleared.

Reassembly and Testing

The console reassembly is just the reverse of its disassembly.

I also managed to find a case that was in better condition and less yellowed.

After its modifications and preventative maintenance, the SNES looked great and worked perfectly! I even bought an SD card cartridge to try out even more of its game library.