National CF-3000 General Maintenance
The National CF-3000 is an MSX1 computer from November 1984 in two parts: a main unit holding the board, power supply and cartridge slots, and a separate keyboard with a numeric keypad.[1] Its rating label gives AC 100 V and 30 W.[2] No service manual for the CF-3000 is among the MSX service manuals held by the MSX Archive, and none has been found elsewhere, so the notes here come from the specification and from photographs of the outside and inside.[3]
Mains supply
[edit | edit source]- The CF-3000 is built for 100 V mains.[2] On 220 to 240 V mains, run it from a step-down transformer with a 100 V output.
- The rear panel has a mains outlet marked "電源コンセント(最大300W) 電源スイッチ非連動": an outlet for up to 300 W that is not switched by the computer's power switch.[2] Anything plugged into it stays live whenever the CF-3000's mains lead is plugged in, and draws its power through the same step-down transformer. Size the transformer for the computer plus whatever is plugged into the outlet, and pull the mains plug out of the wall before opening the case.
Connections
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The rear panel carries, from the left: the mains outlet, the mains lead, the RGB output, the printer, keyboard and superimpose connectors, the audio and video outputs, the RF channel switch (1ch and 2ch) and the RF output.[2] The two joystick ports and the data recorder socket are on the left-hand side of the main unit.[1]
- The 21-pin RGB socket is RGB21, which the MSX Resource Center marks as "not Scart".[1] It uses the same shape of socket as SCART,[2] so check the pinout of any lead before connecting it to a SCART television.
- The superimpose connector is for the optional CF-2601 superimpose unit.[1]
- The keyboard plugs into its own connector on the rear panel.[2] Check that connector's pins and the keyboard lead first when keys stop working.
- Clean the contacts of the RCA sockets and of each connector with isopropyl alcohol if the picture or sound is intermittent.
Cartridge slots
[edit | edit source]Each of the two slots has its own eject button.[1] The slot pinout is part of the MSX standard,[4] so the supply rails can be measured at a slot without opening the case: pins 45 and 47 carry +5 V, pin 48 +12 V and pin 50 −12 V, with pins 41 and 43 as ground.[5] Clean a cartridge's contacts with isopropyl alcohol before blaming the slot, and work the eject mechanism by hand to check that it moves freely.
Opening the main unit
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No dismantling procedure has been published. The photograph of the open unit shows the top cover lifted off a steel chassis.[6] Unplug the mains lead and the keyboard, note where each screw comes from as it is removed, and keep the screws from each panel together.
Inside, the main board takes up the left and centre of the unit, with the printer, keyboard and superimpose connectors on its rear edge and the cartridge connectors at its front.[6] The power supply is at the right: a board with four large electrolytic capacitors and an aluminium heat sink plate, mounted inside an open-topped metal box, with the mains transformer bolted down in front of it and a coloured harness running to the main board.[6]
Electrolytic capacitors
[edit | edit source]The four large capacitors in the power supply box are the main reservoirs, and the main power supply's capacitors are the ones worth replacing as routine on an MSX.[6][7] The main board carries only a handful of small electrolytics.[6] The National CF-3000 Capacitor Replacement Guide covers recording and replacing them.
Keyboard
[edit | edit source]The keyboard is a separate unit, 426 × 40 × 159 mm, with a numeric keypad; the same keyboard design is shown captioned for the CF-3000 and CF-3300.[1] Its inside has not been photographed in a published source. Open it on a soft surface, note the position of each screw, and photograph the key mechanism before lifting anything off.
Related pages
[edit | edit source]- National CF-3000
- National CF-3000 Troubleshooting Guide
- National CF-3000 Capacitor Replacement Guide
- National FS-1300 General Maintenance
- Recommended Tools
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 National CF-3000, MSX Resource Center wiki, 13 April 2019—link(accessed 2026-10-21) Community specification page: one case with a separate keyboard (numeric keypad; the photograph is captioned "CF-3000/3300 keyboard"), NEC D780C-1 (Z80A), 64 KB of RAM in slot 1, TMS9928A video, AY-3-8910 PSG, no MSX-Engine, an eject button for each cartridge slot, no space for a floppy drive; connections listed as RF output, composite video and sound output, "RGB21 output (not Scart)", keyboard connector, Centronics connector for the optional CF-2601 superimpose unit, data recorder connector, Centronics printer port, two general (joystick) ports, two cartridge slots and an AC 100 V power outlet; main unit 428 × 96 × 285 mm, keyboard 426 × 40 × 159 mm, 6.8 kg; gallery photographs of the front, back, label and inside, and of the left side, which shows two 9-pin ports and a round socket.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Rating label and rear panel of the CF-3000, photographed for the MSX Resource Center wiki by Mars2000you, 31 August 2020 (File:National CF-3000 rating label.jpg and File:National CF-3000 rear panel.jpg): "定格電圧 AC100V 定格消費電力 30W", 松下電器産業株式会社; from the left, a mains outlet marked "電源コンセント(最大300W) 電源スイッチ非連動" (outlet, 300 W maximum, not switched by the power switch), the mains lead marked AC100V, RGB output (RGB出力), printer (プリンタ), keyboard (キーボード) and superimpose (スーパーインポーズ) connectors, audio and video outputs (出力 音声 映像), the channel switch (チャンネル切換 2ch/1ch) and the RF output (RF出力).
- ↑ Index of /pub/msx/docs/service_manuals, MSX Archive—link(accessed 2026-10-21) Directory of MSX service manuals; the Panasonic and National entries are the CF-2700 and the turbo R machines.
- ↑ Matsushita Electric Trading Co., Service Manual: Personal Computer CF-2700, order no. IED84113035C2, 1984, printed page 1 (specifications). Hosted here as Panasonic CF-2700 Service Manual. Export model: Z-80A, 64 KB main RAM, TMS 9929A, cassette by FSK at 1200 or 2400 baud, two slots "conforming to MSX specifications", 220 V 50 Hz (240 V for the U.K.), 28 W. Printed page 15, "Cassette Interface Circuit": "MSX uses FSK method for recording, whose transfer rate supports 1200 baud and 2400 baud".
- ↑ Matsushita, Service Manual: Personal Computer CF-2700 (IED84113035C2), printed page 14, Table 7 "Explanation of Signal Lines" for the cartridge slots: pins 41 and 43 ground, 45 and 47 +5 V, 48 +12 V, 50 −12 V, 49 sound input, 44 and 46 SW1 and SW2. See Panasonic CF-2700 Service Manual.
- ↑ 6.0 6.1 6.2 6.3 6.4 File:National CF-3000 inside.jpg, photograph of the inside of the CF-3000 main unit uploaded to the MSX Resource Center wiki by Mars2000you, 31 August 2020. Read from it: the main board fills the left and centre, with the printer, keyboard and superimpose connectors along the rear edge, the cartridge connectors along the front, and only a handful of small electrolytics; the power supply sits at the right in an open-topped metal box holding a board with four large electrolytic capacitors and an aluminium heat sink plate, joined to the main board by a coloured harness; the mains transformer is bolted to the floor in front of it.
- ↑ Recap recommendations, June 2018—link(accessed 2026-10-21) Reply by RetroTechie, 23 June 2018: in an MSX, the electrolytics used for supply bypassing round the board can often be removed without the machine stopping, those in the audio and video circuits show their condition in the output, and those in the main power supply are worth replacing whatever their condition; use the service manual's parts list and compare it with the board, and replace one capacitor at a time. Other replies recommend Rubycon, Chemi-Con, Nichicon or Panasonic parts from established distributors.
