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Panasonic FS-A1F Capacitor Replacement Guide

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Panasonic FS-A1F inside, main board and disk drive
Inside an FS-A1F. The power supply board is at the upper left, with the HIC-1 video board on the main board to its right

The Panasonic FS-A1F has three groups of electrolytic capacitors: three surface-mount parts on the HIC-1 video board, the capacitors on the separate switching power supply board, and the through-hole capacitors on the main board. The first two groups are known to leak and should be replaced first.[1][2] No parts list for the FS-A1F has been published, so the values on the power supply board and the main board have to be read from the parts themselves.

HIC-1 capacitors

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The HIC-1 (Mitsumi EMC-NX0039, Panasonic part DAMCNX0039XT) is the same board as in the Panasonic FS-A1MK2. Its full replacement procedure, with the community's notes on replacement parts, is in the Panasonic FS-A1MK2 Capacitor Replacement Guide.[2]

HIC-1 electrolytic capacitors
Ref Value Voltage Notes
C10 10 µF 16 V Surface-mount aluminium
C14 10 µF 16 V Surface-mount aluminium
C22 100 µF 6.3 V on niga2's FS-A1F; 16 V in sd_snatcher's list Surface-mount aluminium; the one most often found leaking

[3][2] The board runs from +5 V, so 10 V or 16 V parts are safe in all three positions.[4] In outline:

  1. Photograph the board and note the polarity of each capacitor.
  2. Remove each capacitor without heating the pads for long. niga2 twists the can off with side cutters, cutting parallel to the line of its terminals, then lifts away what is left.[2]
  3. Clean off the electrolyte and inspect the joints round the old capacitors. Joints that have turned dull, or smell of electrolyte when heated, have been attacked; scrape corroded tracks back to bright copper and resolder them.[2]
  4. Fit surface-mount or small leaded replacements and do not let them move once soldered, because the pads lift easily.[2]

Power supply board

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The FS-A1F's 100 V switching supply is on a separate board at the left of the case, beside the floppy drive.[5] niga2 found its navy-blue Matsushita electrolytics leaking brown electrolyte, which had run down their legs onto the board and started to corrode the tracks. He replaced every electrolytic on the board, washed the electrolyte off, and recommends low-ESR capacitors because the board is a switching supply.[2]

The board is connected to the mains whenever the lead is plugged in. Unplug the machine and let the capacitors discharge before taking the board out; measure across the largest capacitor before handling the board.

  1. Unplug the supply board's cables from the main board, noting each connector, and take the board out.
  2. Photograph both sides, then each capacitor close up so its printing can be read.
  3. Record each capacitor's designator, value, voltage, temperature rating, size and polarity in the table below.
  4. Replace the capacitors one at a time with low-ESR parts of the same capacitance and at least the same voltage and temperature rating, with the stripe on the same side.[2]
  5. Wash off any leaked electrolyte, scrape and resolder any corroded tracks, and let the board dry completely before refitting it.[2]
Template for the FS-A1F power supply board list
Ref Value Voltage Temperature rating Diameter × height Notes

Main board capacitors

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niga2 found the main board's electrolytics in better condition. They did not need urgent replacement, but he advises replacing them because of their age.[2] No list of their values has been published. Record them as for the power supply board, replace the ones in the video and sound area if the picture or sound is poor, and replace one at a time.[6]

The main board is double-sided with plated through-holes and very fine lands. niga2 damaged several through-holes removing a chip with a 30 W iron and a hand solder sucker, so use a temperature-controlled iron and a desoldering tool, and check continuity through any hole you have reworked.[2]

Template for the FS-A1F main board list
Ref Value Voltage Diameter × height Position Notes

After the recap

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Measure the rails at a cartridge slot: +5 V on pins 45 and 47, +12 V on pin 48 and −12 V on pin 50, with pins 41 and 43 as ground.[7] Check the picture on both composite and RGB, which the HIC-1 produces, and listen to the sound.[4] Remaining faults are covered in the Panasonic FS-A1F Troubleshooting Guide.

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References

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  1. ↑ Panasonic FS-A1F, MSX Resource Center wiki, 7 March 2026—link(accessed 2026-10-21) "The systemboard has a daughterboard called HIC-1 which contains three SMD electrolytic capacitors which will leak over time and badly damage the board around it."
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 FS-A1Fの改造 前編– niga2—link(accessed 2026-10-21) In Japanese. The HIC (Mitsumi DAMCNX0039XT) surface-mount electrolytics need replacing first: the values are printed on their sides, one 100 µF 6.3 V and two 10 µF 16 V; dull solder joints near them smelt of electrolyte when heated; removal: grip the can's waist with side cutters and twist the top off, cutting parallel to the line of the two terminals, then remove the rest of the can and seal, cut the legs and lift the base; leaded capacitors can be fitted; the pads lift very easily, so the new parts must not be allowed to move; one badly corroded pad was bypassed by soldering the capacitor straight to the IC's pin; corroded tracks can often be scraped back to bright copper with a craft knife and resoldered. The FS-A1F's switching supply: the navy-blue Matsushita electrolytics had leaked brown electrolyte that ran down their legs and had begun to corrode the tracks, needing urgent attention; all the electrolytics were removed, the electrolyte washed off and new ones fitted; low-ESR electrolytics recommended for a switching supply. The main board electrolytics do not need replacing urgently, but given their age replacing them is better.
  3. ↑ Urgent alert to MSX2/2+ owners: suicide capacitors on HIC-1 daughterboard, July 2015 onwards—link(accessed 2026-10-21) sd_snatcher, 19 July 2015: replace C10 (10 µF 16 V), C14 (10 µF 16 V) and C22 (100 µF 16 V), C22 being the worst; replace them even in machines in storage; ceramic or tantalum replacements are possible, all rated 16 V or more. RetroTechie: remove the old parts by cutting through the solder with a sharp knife, or with two soldering irons, one on each end.
  4. ↑ 4.0 4.1 BABAX, Mitsumi Hybrid IC EMC-NX0039 (Panasonic parts no. DAMCNX0039XT), revision 02. File:Mitsumi EMC-NX0039 HIC-1 schematic (BABAX, Rev 02).pdf; see HIC-1 Hybrid Board Schematic. +5 V supply; HIC_C22 100 µF.
  5. ↑ File:Panasonic FS-A1F inside, main board and disk drive.jpg, photograph uploaded to the MSX Resource Center wiki by Keith56 on 30 July 2017: the power supply board, with its small transformer, fuse and electrolytic capacitors, at the upper left.
  6. ↑ Recap recommendations, June 2018—link(accessed 2026-10-21) RetroTechie, 23 June 2018: main power supply electrolytics are worth replacing whatever their condition; audio and video ones show their condition in the output; replace one capacitor at a time.
  7. ↑ MSX Cartridge slot, MSX Resource Center wiki, 6 July 2026—link(accessed 2026-10-21) Pins 41 and 43 GND, 45 and 47 +5 V, 48 +12 V, 50 −12 V.



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