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Recap guide

Recap the Sega Master System

A modest cap count. SMS II recaps are common during RGB and regulator refreshes, but we found no documented failure epidemic. One write-up lists values for an early PAL SMS II board.

Open the interactive checklist Tick off each capacitor as you replace it. It saves in your browser.

Check first. A recap is not always the answer here, so look at the guides before you order parts.

Which board do I have?

Boards changed during production. These notes come from the linked sources, and many are only partly documented, so check the board in front of you.

  • Mark III 171-5304 (Japan, 1985-1987) (Medium confidence). How to tell: Original Japanese console with the expansion port on the left and a built-in card slot; only one board revision. Capacitors: No capacitor information found. Capacitor list differs from other revisions: not known. Source
  • 171-5379 / 837-6067 (NTSC SMS1, 1986-1987; also France) (Medium confidence). How to tell: First NTSC revision with double-sided plated-through solder joints and a Sony V7040 video encoder. Capacitors: ConsoleMods' board page lists 29 capacitors: electrolytics from 10 to 180 uF at 10V or 16V plus film or ceramic parts; mounting style is not stated. Capacitor list differs from other revisions: not known. Source
  • 171-5532 / 837-6405 (NTSC SMS1, 1988) (Medium confidence). How to tell: Cost-reduced board with single-sided solder joints and a CXA1145 encoder. Capacitors: No cap list found. Capacitor list differs from other revisions: not known. Source
  • 837-6629 and 837-6700 (NTSC SMS1, 1988-1992) (Medium confidence). How to tell: Later NTSC boards; 837-6700 adds the 315-5330 logic array and one 32 KB PSRAM for video. Capacitors: No cap list found. Capacitor list differs from other revisions: not known. Source
  • PAL SMS1 171-5385, 171-5534 VA1, 171-5672 VA2, 171-5535-10 VA3 (Medium confidence). How to tell: 171-5385 hides its clock circuit under a soldered shield, VA1 uses rubber dome switches, VA2 adds a reverse-polarity diode, and VA3 is a major redesign with a 4-pin oscillator. Capacitors: No cap list found. Capacitor list differs from other revisions: not known. Source
  • Master System II 171-5922A (early PAL, 1990-1991) (Medium confidence). How to tell: Initial PAL SMS2 board introduced in Australasia in late 1990 and Europe in 1991, marked 171-5922-A. Capacitors: A Retro Repairs log lists 15 through-hole electrolytics (six 10uF 16V CE positions, C18 10uF 16V, C31 1uF 50V, C32 10uF 16V, C38, C41, C42, C43 100uF 16V, C44 47uF 10V, C54 10uF 16V) and says SMS2 variants have different cap values and locations; ConsoleMods lists 26 capacitor entries for the same board. Capacitor list differs from other revisions: yes. Source
  • Master System II later boards (M4Jr VA1, 171-6395A PAL 2M, 171-6416A 2M) (Medium confidence). How to tell: M4Jr VA1 has the built-in Alex Kidd, while 171-6395A and 171-6416A carry a 2-megabit BIOS with built-in Sonic. Capacitors: No cap list found. Capacitor list differs from other revisions: not known. Source
  • Master System III Compact (Brazil) (Low confidence). How to tell: Brazilian compact model, mix of through-hole and SMD parts. Capacitors: ConsoleMods says it mixes through-hole and SMD components; no values given. Capacitor list differs from other revisions: not known. Source

Where to start

We did not find a clear list of what fails first on this machine, so we are not guessing. Read the guides below, check the board for leaks, and replace what you can see.

Tips, tales and maybes

Found in write-ups and forum threads. These are other people's reports, not tested by us. Check part references and values against your own board.

  • Watch out: Polarity and silkscreen errors (Medium confidence). A restoration write-up on an SMS II (PAL 171-5922-A, 15 electrolytics) warns that wrongly oriented electrolytics run hot and can burst, and that the board silkscreen sometimes has factory orientation errors. It advises replacing one cap at a time and taking photos of the original first. Source
  • Tip: High heat for the modulator and DIN (Medium confidence). The same write-up says the original RF modulator and DIN connector need a high-power iron to remove and refit because of their thermal mass. It also recommends a thorough isopropyl clean after the work. Source

Before you start

  • Boards changed during production. Check your board number against the guides before you order parts.

Guides we used

This page and the interactive bench are built from these. They have the photos and the full detail, so please read them and support their authors.

The capacitor list

We have not checked a capacitor list for this machine yet, so none is shown. Follow the guide above for your board, then add the capacitors in the interactive checklist and it builds a shopping list for you.

Skip the sourcing

While you are in there

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Steps, tools and safety

The steps, the tools in top, middle and budget picks, and the safety list are the same for every machine, so they live on one page: How to recap, step by step.

Values are shown as published in the guides above, and boards changed during production. Check the board in front of you. A recap involves hot tools and, on some machines, dangerous voltages. You do it at your own risk.

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