My lovely wife kindly bought me six vintage games consoles for Christmas 2023, all in unknown or non-working condition, including my first SEGA Saturn.
The Saturn is a fifth-generation home video game console developed by SEGA, the successor to the Mega Drive. The Saturn has a dual-CPU architecture and eight processors. Its games are in CD-ROM format, including several ports of arcade games and original games. The Saturn was initially successful in Japan but not elsewhere, being hindered by a surprise launch four months before its scheduled release date. After the debut of the Nintendo 64 in late 1996, the Saturn rapidly lost market share – at 9.26 million units sold worldwide, the Saturn is considered a commercial failure. Although the Saturn has several well-regarded games, its reception is mixed due to its complex hardware design and limited third-party support. The Saturn was succeeded in 1998 by the Dreamcast.
SEGA Saturns are fairly rare due to their limited market success, and even in non-working condition they can fetch quite a lot of money – they go for quite a bit more when refurbished and modified, and the rarer variants can fetch a huge amount of money. Their nostalgia value and interesting game library make them quite collectible.
On its arrival, it seemed to be in quite good physical condition. It seems to be a PAL “Model 1” Saturn, with oval buttons. I bought a suitable RGB SCART cable, then tried it out – unfortunately, it would only output a blank black screen, but the activity LED flashed and the power LED lit up correctly.
The first step was to disassemble the unit and check over everything inside.
Disassembling the Saturn
The SEGA Saturn is easy to dismantle with basic tools: remove the five Philips screws around the perimeter of the underside of the case, and the upper case can be lifted up.
With the case opened, you get your first look inside the console – everything seemed to be original and pretty much untouched.
The power supply is held in by two Philips screws by the power connector, one Philips screw in the bottom-left, and the mains cable from the power switch which just unclips.
The CD-ROM drive is held in place with a ribbon cable, a power cable, and a single Philips screw underneath it holding its ground strap in place.
The mainboard and its RF shielding are held into the bottom case by seven Philips screws around its perimeter; the I/O board and its RF shielding are held into the bottom case by two Philips screws by the front of the unit.
Black Screen Repair
Black screen faults are apparently quite a common problem on the SEGA Saturn, and can be caused by a wide variety of issues: some are relatively simple to repair, such as failed internal PSUs, bad SMD electrolytic capacitors on very early mainboards, or even just needing a new PRAM battery and/or PRAM reset; some are much more difficult to repair, such as corrosion due to factory contamination, or failed proprietary ICs due to overheating/overuse. Some specialists recommend staying away from Saturns with black screen issues, due to a large percentage of them being practically irreparable.
The mainboard was quite dusty, so I cleaned the reset switch, power switch, game cartridge slot, and expansion port with contact cleaner – but, no change in symptoms.
I tested the basics first, power and reset: all power rails seemed OK (+3.3Vdc, +5Vdc, and +9Vdc from the internal PSU); the reset line out of the reset switch also seemed OK.
I gave the mainboard a detailed look over to try and spot anything awry – any liquid spills, bad solder joints, damaged components, bulging or leaky electrolytic capacitors, damage to the board and traces, etc. One thing that I did spot was some blue/green corrosion on several pins of IC1, which is one of the Saturn’s CPUs.
I cleaned off the corrosion gently using a pair of tweezers, then 99.9% IPA and an ESD-safe brush. The traces underneath were dark due to the corrosion – when cleaned further, it was quite clear even by eye that there were clean breaks in the copper on two traces, which became even more obvious when the copper was tinned with solder.
The small breaks in the two traces are more clearly visible under a microscope.
It’s difficult to tell from the pictures, but the pins on this CPU IC are very fine-pitch and small, the traces running to them even more so – I put off attempting this repair work for a week because I was convinced that I’d mess it up, it’s very delicate.
The traces are so fine and the breaks so small that my smallest 0.28AWG wrapping wire was too thick for the repair, so I ended up using an individual strand from one of my smaller multi-core cables instead.
I tinned the traces and wire with leaded solder, added some flux paste to the area, and managed to bridge the two breaks with the wire using my smallest soldering iron tip.
With the two damaged traces bridged, I cleaned up the board with 99.9% IPA.
I tested the console again, and it now seemed to boot up and work fine!
With the console working, I wanted to perform some preventative maintenance (replacing all of the aluminium electrolytic capacitors on the mainboard, power supply, CD-ROM board, and I/O board, servicing the CD-ROM drive, and replacing the PRAM battery).
Console Servicing
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.
There are several production variants of the SEGA Saturn mainboard, I/O board, power supply, and CD-ROM, each of which have different electrolytic capacitor values and locations, so take note of which you have.
There are commercial capacitor packs available for most variants of the SEGA Saturn, but I just made up my own by noting the specifications of all of the electrolytic capacitors on the boards, and ordering a set of high-quality known-brand parts.
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.
I usually remove each capacitor 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.
The mainboard in this Saturn was an early-ish PAL board, marked “VA SD / VA PAL SD: 837-12133” – this has the following through-hole electrolytic capacitors:
- CE1: 100uF 6.3V
- CE3: 100uF 6.3V
- CE7: 100uF 6.3V
- CE15: 10uF 16V
- CE16: 10uF 16V
- CE18: 100uF 6.3V
- CE19: 100uF 6.3V
- CE20: 10uF 16V
- CE21: 10uF 16V
- CE22: 4.7uF 25V
- CE23: 10uF 16V
- CE24: 220uF 4V
- CE25: 220uF 4V
- CE26: 220uF 4V
- CE27: 220uF 4V
- CE28: 220uF 4V
- CE29: 220uF 4V
- CE30: 100uF 6.3V
- CE31: 10uF 16V
- CE33: 22uF 6.3V
- CE34: 22uF 6.3V
- CE35: 47uF 6.3V
- CE37: 10uF 6.3V
- CE42: 10uF 16V
- CE45: 330uF 6.3V
- CE46: 220uF 6.3V
- CE47: 1uF 50V
- CE48: 1uF 50V
- CE49: 47uF 6.3V
- CE50: 47uF 6.3V
- CE52: 10uF 16V
- CE53: 47uF 6.3V
- CE55: 47uF 6.3V
- CE58: 10uF 16V (PAL boards only)
The CD-ROM board was a JVC EXL-P604, with the following parts:
I also cleaned all of the connectors with contact cleaner, cleaned and lubricated the laser head rails, and cleaned the laser itself with 99.9% IPA and a cotton bud.
The front I/O board only has a couple of electrolytic capacitors:
The internal power supply was a Fujitsu KS350-1401-H025/01, with the following parts:
- C5: 33uF 400V
- C10: 4700uF 10V
- C12: 2200uF 16V
- C15: 330uF 16V
- C16: 330uF 16V
- C24: 330uF 16V
- C50: 2200uF 10V
- C72: 47uF 16V
I also cleaned all of the connectors with contact cleaner, and reflowed most of the larger solder joints across the board to help prevent cracking.
Reassembly and Testing
The console reassembly is just the reverse of its disassembly.
After its modifications and preventative maintenance, the Saturn looked great and worked perfectly! I even bought an SD card cartridge to try out even more of its game library.
Adam's Vintage Computer Restorations 
Are you a technical expert on the Sega Saturn? If so, do you know how to get a Sega Saturn cartridge slot working? Mine won’t read anything no matter what I try and to make full use of it would be nice because some games use it.
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Hi vanhalbgott,
The best thing that I have found for cleaning pins is a light wet sand with 1000 grit sandpaper and some contact cleaner. I then finish it off with a toothbrush and some 99% IPA. Hope that helps!
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