Sharp X1C General Maintenance
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These notes cover the Sharp X1C (CZ-801C) and its variants, the X1Cs (CZ-803C) and X1Ck (CZ-804C). No Sharp owner's manual or service manual for these models was found on the Internet Archive or X1 Center. The X1C runs the same system and uses the same kind of data recorder as the first X1, so Sharp's handling notes for the first X1, on Sharp X1 General Maintenance, are the nearest official guidance. Where they are used below, the text says so.
Safety
[edit | edit source]The X1C has a mains power unit inside the case, rated by Sharp at AC 100 V and 30 W.[1] The schematic headed "X1C" in X1システム研究室, which matches the X1Cs and X1Ck, shows the power unit feeding the main board with two 5 V supplies (VCC1 and the standby supply VCC2) and the cassette interface with a 12 V supply (VCC3).[2] No circuit of the power unit itself has been published.
- Switch off and unplug the mains lead before taking any screw out.
- Do not touch the power unit's board until its capacitors have discharged; measure across the large capacitors first.
- For the first X1, Sharp warns against switching on with the cover removed and against leaving screws inside the case.[3] The same care applies to the X1C.
Everyday care
[edit | edit source]Sharp's care notes for the first X1 cover ventilation, damp and dust, cleaning the case with a soft damp cloth and no solvents, leaving at least 10 seconds between switching off and on, and cleaning the cassette head once a month.[4] The X1C has the same kind of full-logic data recorder at the same 2700 baud, so the head-cleaning advice applies to it as well.[1]
Opening the case
[edit | edit source]No disassembly procedure for the X1C has been published. X1 Center reports that the keyboard's internal connector can be reached easily by opening the cover of the bay that takes the optional plotter printer, at the upper left of the computer.[5][6] For deeper work:
- Unplug the computer and photograph it from each side before starting.
- Remove one cover at a time, keep the screws from each in a separate labelled container, and note any screws of a different length.
- Photograph each cable and connector before unplugging it.
Keyboard
[edit | edit source]The X1C's keyboard is built into the case but is a separate circuit, compatible with the separate keyboards of the other X1 models.[5]
- Its internal connector has three wires, brown, red and orange. X1 Center fitted a 3.5 mm mini jack to these and used the X1C keyboard on an X1turbo Z, with no power to the X1C.[5]
- The X1C has a rear socket for an external keyboard.[5][2] With its own keyboard plugged in there through such an adapter, the EJECT key does not work; SHIFT+STOP ejects the tape instead.[5]
- X1 Center's notes apply to the CZ-801C. On the X1Cs and X1Ck the connector may be in a different place, although the plug and wire colours may match.[5]
Cassette deck
[edit | edit source]The X1C's data recorder is a full-logic electromagnetic deck under program control, like the first X1's.[1] X1 Center's belt measurements were taken on the first X1's deck and are listed in Sharp X1 General Maintenance. The only X1C entry in that list is the tape counter belt: a Nisshinbo Mobilon band, medium size (80 mm lay-flat, 0.3 mm thick, 3 mm wide), worked in an X1C.[7] Measure the X1C's other belts before ordering replacements.
Clock
[edit | edit source]The X1C, X1Cs and X1Ck have no clock backup battery, so there is no cell to leak on the board.[8] The clock chip takes its supply from the standby supply VCC2 through diode D5, with C39 (100 µF) and C43 (47 µF) on its supply.[2]
After any work
[edit | edit source]- Check that no screws or offcuts are left inside, and refit every cover before switching on.
- Switch on. The X1 series IPL looks for a floppy drive, a ROM board and the cassette in turn, then shows its menu.[9]
- Load a program from tape and press every key, including the cassette and television control keys.
Maintenance checklist
[edit | edit source]| Task | When |
|---|---|
| Clean the cassette head | Monthly in use (Sharp's advice for the first X1) |
| Check the deck belts | When the deck misbehaves, or before using a machine that has been stored |
| Inspect the case vents and clean the case | Whenever the computer is moved or stored |
Related pages
[edit | edit source]- Sharp X1C
- Sharp X1C Troubleshooting Guide
- Sharp X1C Capacitor Replacement Guide
- Sharp X1 General Maintenance, for the first X1
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Oh!MZ, November 1983 (Nihon SoftBank), page 26, table 1 "パーソナルコンピュータ(CZ-801C/802C)仕様": full-logic electromagnetic cassette deck built in (X1C), Sharp PWM, 2700 baud; AC 100 V ±10 %, 50/60 Hz; 30 W (X1C). Scan on the Internet Archive, item oh-mz-1983-08-12, file Oh!MZ_1983-11, leaf 27.
- ↑ 2.0 2.1 2.2 有田隆也 (Arita Takaya), X1システム研究室 (Nihon SoftBank, 1985), pages 279 to 283, "X1C全回路図" (X1 Center identifies it as the X1Cs and X1Ck schematic): power input connector I-1 GND, I-2 VCC1, I-3 VCC2; cassette interface supplied with VCC3 (12 V) from the power unit; external keyboard jack J2 (GND, VCC2, DATA); clock chip supplied from VCC2 through D5, with C39 100 µF 10 V and C43 47 µF 10 V. Scan on the Internet Archive, item x-1_TechnicalDocuments, leaves 281 to 285.
- ↑ CZ-800C 取扱説明書, File:Sharp X1 CZ-800C Owner's Manual (Japanese).pdf, page 63 of the scan: do not switch on with the cover removed (risk of damage and electric shock) and do not leave screws or other metal inside.
- ↑ Sharp Corporation, パソコンテレビX1 パーソナルコンピュータ CZ-800C 取扱説明書 (owner's manual for the first X1, Japanese), File:Sharp X1 CZ-800C Owner's Manual (Japanese).pdf, pages 10 and 11 of the scan: keep the ventilation holes clear; avoid damp, dust and heat; clean with a soft cloth dampened with water or detergent, never benzine or thinners; leave at least 10 seconds between switching off and on; clean the cassette record and playback head once a month.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 X1Cを、他のX1/X1turboのキーボードにする。, X1 Center, 2009-01-16—link(accessed 2026-10-21) The X1C keyboard is independent of the main unit and compatible with the separate X1 keyboards; its connector is easy to reach by opening the cover for the add-on plotter printer; three wires, brown, red and orange; with a 3.5 mm mini jack it works on other X1 and X1turbo models, tested on an X1turbo Z, without powering the X1C; it can also be used through the X1C's own rear keyboard connector, where EJECT does not work but SHIFT+STOP does; applies to the CZ-801C, and the connector may be placed differently on the X1Cs and X1Ck.
- ↑ Oh!MZ, November 1983, colour page "ファン待望のニューフェイス": the full-logic cassette deck is at the upper right above the keyboard, with the colour plotter printer bay to its left. Scan on the Internet Archive, item oh-mz-1983-08-12, file Oh!MZ_1983-11, leaf 18.
- ↑ CZ-800Cカセットデッキの修理メモ, X1 Center—link(accessed 2026-10-21) Tape counter square belt (CZ-800C deck): Nisshinbo Chemical Mobilon band, medium (80 mm lay-flat × 0.3 mm × 3 mm), confirmed working on an X1C.
- ↑ 搭載チップセット, X1 Center—link(accessed 2026-10-21) Backup battery: none on the CZ-801C (X1C), CZ-803C (X1Cs) and CZ-804C (X1Ck); 2.4 V 30 mAh on the CZ-800C (X1) and CZ-802C (X1D).
- ↑ X1 (コンピュータ), Japanese Wikipedia—link(accessed 2026-10-21) At power-on the IPL tries the floppy drive, a ROM board and the cassette in turn; if none answers, or the user cancels, it shows a menu of the three boot devices and the TV timer editor.