National FS-5500 Capacitor Replacement Guide
No capacitor list for the National FS-5500 has been published. Photographs of its boards show where the electrolytic capacitors are; record the values from your own machine before ordering parts.
What the photographs show
[edit | edit source]| Board | What can be seen |
|---|---|
| Video board | Several dozen small radial electrolytics, mostly blue, among the video ICs and trimmer potentiometers, and one large can at the bottom right beside connector CN301[1] |
| Main board | A large blue can marked 16 V lying flat at the top left; groups of radial electrolytics near the top edge, in the middle and beside the power connector at the right edge[2] |
| ROM and RAM board | Two, one at the lower left and one beside the TMS4464 DRAMs[3] |
| Expansion slot board | None visible[4] |
| Power supply unit | Not photographed with its cover off |
The main board also carries a yellow cylindrical cell held by a cable tie.[2] Check it for leakage while the board is out; see Battery Explosion, Capacitor or Corrosion Damage.
Which to replace first
[edit | edit source]Advice on the MSX Resource Center forum is to replace the main supply's capacitors whatever their condition, to judge the audio and video capacitors by the picture and sound, and to leave the small decoupling capacitors unless they show a fault.[5] On the FS-5500 that means:
- The capacitors inside the power supply unit.
- The video board, if the picture, the superimposed video or the sound is poor. It holds most of the small electrolytics in the machine.
- The main board and the ROM and RAM board, if a capacitor shows leakage or bulging.
See Capacitor Failure Symptoms for what a failed capacitor looks like.
Recording your boards
[edit | edit source]- Unplug the computer. The power cord, power switch, rear outlets, fuse holder and power supply unit carry mains voltage.[6]
- Open the case, photographing each screw and connector; see the National FS-5500 General Maintenance guide.
- Unplug the video board and the ROM and RAM board from the main board, holding each by its edges.[6]
- Photograph each board from above, then each electrolytic close up so the printing on its sleeve can be read.
- Write down each capacitor's designator, capacitance, voltage, diameter, height and the side its stripe faces.
- Order replacements with the same capacitance, at least the same voltage, and a size that fits.
| Board | Ref | Value | Voltage | Diameter × height | Notes |
|---|---|---|---|---|---|
| Power supply unit | |||||
| Video | |||||
| Main | |||||
| ROM and RAM |
Replacing them
[edit | edit source]- Replace one capacitor at a time, with the stripe on the same side as the original.[5]
- The video board has many trimmer potentiometers. No adjustment procedure for them has been published, so leave them as found.[1]
- Clean off any electrolyte and look at the tracks under the capacitors for corrosion.
Checks after the work
[edit | edit source]Switch on and measure at a front cartridge slot against pin 41: +5 V on pins 45 and 47, +12 V on pin 48, −12 V on pin 50.[7] Check the picture on composite and RGB, a superimposed video input, the sound and a disk boot. Remaining faults are covered in the National FS-5500 Troubleshooting Guide.
Related pages
[edit | edit source]- National FS-5500
- National FS-5500 General Maintenance
- National FS-5500 Troubleshooting Guide
- Capacitor Failure Symptoms
References
[edit | edit source]- ↑ 1.0 1.1 File:National FS-5500 video board.jpg, photograph uploaded to the MSX Resource Center wiki by Rderooy on 27 September 2016: video board with edge connector CN301 (marked VIDEO), Matsushita AN-series ICs including an AN5316, cream trimmer potentiometers, many small radial electrolytic capacitors (mostly blue) and one large electrolytic at the bottom right; the printed values cannot be read at the published resolution.
- ↑ 2.0 2.1 MSX Resource Center wiki, File:Fs5500f1f.jpg, "National FS-5500 PCB", uploaded by Mars2000you on 13 September 2020 (the same photograph appears on USB Secret Base): main board DFUP0038ZA with a large blue electrolytic marked 16 V lying flat at the top left, radial electrolytics near the top edge, in the middle of the board and beside the white power connector at the right edge, and a yellow cylindrical cell held by a cable tie.
- ↑ File:National FS-5500 ROM and RAM board.jpg, photograph uploaded to the MSX Resource Center wiki by Rderooy on 27 September 2016: board DFUP0039ZA with two radial electrolytic capacitors, one at the lower left corner and one beside the TMS4464 DRAMs.
- ↑ File:National FS-5500 expansion slot board.jpg, photograph uploaded to the MSX Resource Center wiki by Gdx on 26 February 2018: board DFUP0040ZAG carrying only connectors and jumper positions.
- ↑ 5.0 5.1 Recap recommendations, June 2018—link(accessed 2026-10-21) RetroTechie, 23 June 2018: in an MSX, the main power supply capacitors are worth replacing whatever their condition; capacitors in the analogue audio and video circuits show their condition in the output; supply bypass capacitors round the board can often be removed without the machine stopping; replace capacitors one at a time. Wlcracks: use Rubycon, Chemi-Con, Nichicon or Panasonic parts.
- ↑ 6.0 6.1 National FS-5500, USB Secret Base (up-c), 2010 to 2017—link(accessed 2026-10-21) Rear panel: switched and unswitched AC 100 V outlets, fuse (125 V 3 A), power cable. Inside: power supply unit, expansion slot board, memory board, video board; the memory and video boards plug into a 64-pin and a 50-pin connector on the main board.
- ↑ MSX Cartridge slot, MSX Resource Center wiki, 6 July 2026—link(accessed 2026-10-21) Standard MSX cartridge slot: 41 and 43 GND, 45 and 47 +5 V, 48 +12 V, 50 −12 V.
