Sharp X1 Turbo Z General Maintenance
These notes cover the Sharp X1turbo Z series (CZ-880C, CZ-881C and CZ-888C). Sharp's instructions come from the CZ-880C owner's manual, which also explains how to open the case and take out the floppy drives. No Sharp service manual for these models was found. Fault finding is on Sharp X1 Turbo Z Troubleshooting Guide.
Safety
[edit | edit source]The power supply is inside the main case. Pressing the front power switch does not turn the computer fully off: the television control and timer circuits stay powered until the main power switch on the back is turned off.[1]
- Turn off the front power switch, then the rear main power switch, and unplug the mains lead before taking any screw out.[1]
- Leave the computer unplugged for a while before touching the power supply, and measure across its large capacitors before working on it.
Everyday care
[edit | edit source]Sharp's handling notes for the X1turbo Z are:[2]
- The computer is cooled by a fan. Keep the ventilation holes clear, do not push it into a tight space or stand it on carpet or bedding, and leave at least 10 cm of space on its right-hand side.
- Keep it away from damp and dust. The fan can draw dust into the case.
- Keep it out of direct sunlight and away from heaters, which can damage the cabinet, the parts inside and floppy disks.
- In an electrically noisy place, use a mains line filter, and keep the RGB and TV control cables away from other mains leads.
- If liquid or a metal object gets inside, unplug the computer at once and have it checked. Do not drop it or knock it.
- Clean the case with a soft cloth dampened with water or a little detergent. Benzine, thinners and other solvents can lift the cabinet's paint.
- Condensation can form inside when the computer is brought from the cold into a warm room, in a steamy or very damp room, or in a room that has just been heated. Wait for it to clear before switching on.
- A static picture left on the display television for a long time can burn into the screen.
Because the fan draws air through the case, look for dust on the fan and the vents whenever the case is open.[2]
Power switches
[edit | edit source]- Leave at least 10 seconds between switching off and switching on again, so that the computer starts reliably. Do not plug in or unplug the mains lead with a power switch on.[1]
- With the display television, switch on with the rear main power switch first and then the front power switch. Switch off in the reverse order.[1]
- Plugging the keyboard in while the main power switch is on can make the computer misbehave. Leave the keyboard plugged in, turn the main power switch off and then on again.[1]
- If the computer will not be used for a long time, turn the main power switch off and unplug it.[1]
Opening the case
[edit | edit source]Sharp's procedure for taking out the internal floppy drives starts with the top cover:[3]
- Remove the four screws on the sides and loosen the two screws on the back.
- Pull the top cover towards the back and lift it off.
- To reach the drives, remove the ten screws holding the drive mounting plate and lift the plate off.
Refit the plate with its ten screws and the top cover in the reverse order.[3]
Floppy drives
[edit | edit source]The X1turbo Z's drives are TEAC FD55GFV-73 three-mode (2D, 2DD and 2HD) drives. They step at 6 ms in 2D mode and 3 ms in 2DD and 2HD modes, and return to track 0 at power-on. The Z II uses the FD55GFR-345 and the Z III the FD55GFR-045. X1 Center found that the internal drive cable cannot be replaced on any of the three models.[4]
To take out a drive:[3]
- Open the case and remove the drive mounting plate as above.
- Unplug the four-pin power lead and the signal connector from the back of the drive.
- Turn the drive's front lever horizontal and slide the drive out through the back.
- To refit it, keep the lever horizontal, slide the drive in from the back until its front is flush with the front of the cabinet, and reconnect both leads.
Each drive's number is set by the strap block (DS0 to DS3) on its underside. The internal drives are 0 and 1. An external drive must be set to 2 or 3; the CZ-520F already is. If two drives share a number the system does not work properly and the drives can be damaged.[3]
X1 Center notes that the FD-55GFV-40-U drive from the NEC PC-8801MR looks usable as an internal drive for the X1turbo Z and later models, but has not confirmed it.[4]
Disk mode switch
[edit | edit source]The DIP switch on the back sets the disk type the computer starts from. Sharp ships it set so that the front start-up disk type switch decides.[5]
| SW1 | SW2 | SW3 | SW5 | SW6 | Disk type |
|---|---|---|---|---|---|
| Any | Any | Any | ON | ON | Front switch decides: 2HD or 2D |
| Any | Any | Any | ON | OFF | Front switch decides: 2HD or 2DD |
| ON | ON | ON | OFF | ON | 0: 5¼-inch (or 3-inch) 2D, 320 KB, X1 format |
| OFF | ON | ON | OFF | OFF | 1: 5¼-inch (or 3-inch) 2DD, 640 KB, X1 format |
| ON | OFF | ON | OFF | Any | 2: 5¼-inch 2HD, 1 MB, X1 format |
| OFF | OFF | ON | OFF | Any | 3: 5¼-inch 2HD, 1 MB, standard format |
| ON | ON | OFF | OFF | Any | 4: 8-inch 2D 256, 1 MB, X1 format |
| OFF | ON | OFF | OFF | Any | 5: 8-inch 2D 256, 1 MB, standard format |
| ON | OFF | OFF | OFF | Any | 6: 8-inch 1S 128, 240 KB, standard format |
| OFF | OFF | OFF | OFF | Any | 7: hard disk, 10 MB, X1 format |
SW4 is set on at the factory and should not need changing.[5] X1 Center found that the 2D/2DD signal to the internal drives follows switch 6 only. Software can neither set nor read it, and it does not reach the external drive connector.[4]
Interface boards
[edit | edit source]The two internal expansion slots are behind a panel on the back.[6]
- Remove the two screws holding the connector panel and take the panel off.
- Remove the two screws holding the slot cover to the panel.
- Slide the interface board, component side up, along the slot's guide rails until it seats fully in the connector.
- Fix the board to the panel with the cover screws and refit the panel. A board with no rear connectors does not need the cover removed.
Clock backup battery
[edit | edit source]The clock is backed up by a nickel-cadmium cell inside the computer.[7] These cells leak with age. X1 Center found blackened, corroded plated holes around the cell on an X1turbo III board, and the Sharp Museum removed the rechargeable cell from its X1turbo to stop it leaking.[8][9]
- Look at the cell and the board around it whenever the case is open.
- If the clock does not need to keep time with the power off, X1 Center suggests removing the cell or fitting a 5.5 V supercapacitor in its place.[8]
Keyboard
[edit | edit source]- A keyboard that works only while its plug is pressed one way has cracked solder joints on the keyboard connector inside the computer; reflow them. X1 Center lists this as a common fault on the X1, turbo and Z series.[10]
- X1 Center found that the coiled cords of X1 and X1turbo keyboards go white and crumble with age. The X1turbo Z keyboard also uses a coiled cord. On the X1 and X1turbo the keyboard line carries +5 V, so replace a cracked cord; the method is on Sharp X1 General Maintenance.[11][7]
After any work
[edit | edit source]- Check that no screws or offcuts are left inside, and refit every cover before switching on.
- Check the disk mode DIP switch and the start-up disk type switch behind the front door.
- Switch on at the rear main power switch, then the front power switch, and start Disk BASIC from its system disk.
- Test both floppy drives, the clock and the sound.
Maintenance checklist
[edit | edit source]| Task | When |
|---|---|
| Check the fan and vents for dust | Whenever the case is open |
| Check the clock cell for leakage | Whenever the case is open |
| Inspect the keyboard cord | Whenever the keyboard is handled |
| Check the drive-select straps | After fitting or swapping a floppy drive |
Related pages
[edit | edit source]- Sharp X1 Turbo Z
- Sharp X1 Turbo Z Troubleshooting Guide
- Sharp X1 Turbo Z Capacitor Replacement Guide
- Sharp X1 Turbo General Maintenance, for the X1turbo
- Sharp X1 General Maintenance, for the first X1
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 X1turboZ CZ-880C 取扱説明書, page 31, power notes: use AC 100 V; leave at least 10 seconds between switching off and on; do not plug or unplug the mains lead with the switch on; with the display television, turn on the rear main power switch and then the front power switch, and turn off in the reverse order; plugging in the keyboard with the main power switch on can cause malfunction, in which case leave the keyboard plugged in and turn the main switch off and on again; the front switch turns off the POWER lamp but not all power, as TV control by key and the timer still work; turn the rear main power switch off to cut power completely; if unused for a long time, turn the main switch off and unplug.
- ↑ 2.0 2.1 Sharp Corporation, X1turboZ CZ-880C 取扱説明書 (owner's manual, Japanese, December 1986), pages 29 and 30, installation and handling precautions: the cabinet has ventilation holes; do not block them; the computer uses an air-cooling fan, so leave at least 10 cm of space on its right; avoid damp and dust, especially as the fan can draw in dust; avoid direct sunlight and heaters; use a line filter in noisy places and keep the RGB and TV control cables away from other power cords; liquids or metal objects inside are dangerous, so unplug and contact the dealer; do not drop or knock it; screen burn on the display; use only Sharp-specified equipment; clean with a soft cloth moistened with water or detergent, not benzine or thinner, which can lift the paint; condensation forms in damp or steamy places, when moved from a cold place into a warm room, or in a room just heated, and can cause malfunction. Hosted as Sharp X1turbo Z CZ-880C Owner's Manual (Japanese).pdf.
- ↑ 3.0 3.1 3.2 3.3 X1turboZ CZ-880C 取扱説明書, pages 62 and 63: the internal and external drives are both numbered 0 and 1, so one pair must be changed to 2 and 3 or the system will not work properly and the drives may be damaged (the CZ-520F is already 2 and 3); removing a mini floppy drive: remove the 4 screws on the sides and loosen the 2 screws on the back, pull the top cover towards the back to remove it; remove the 10 screws of the drive mounting plate and take the plate off; disconnect the 4-pin connector lead and the connector at the back of the drive; with the front lever horizontal, take the drive out from the back; change the drive number with the strap on the underside of the drive; refit with the lever horizontal, pushing in until the drive front is flush with the front cabinet; reconnect, refit the plate with 10 screws, refit the top cover; strap settings DS0 to DS3 for drive numbers 0 to 3.
- ↑ 4.0 4.1 4.2 X1/turbo/Zシリーズ搭載FDDインターフェース仕様, X1 Center—link(accessed 2026-10-21) CZ-880C, CZ-881C and CZ-888C: 2HD, FM and DMA supported; internal drive 2D/2DD/2HD switching yes, by DIP switch 6 only, with no software control or detection, and the signal is not connected to the expansion connector; internal FDD cable not replaceable; CZ-880C internal drives FD55GFV-73 (19307200-73), CZ-881C FD55GFR-345, CZ-888C FD55GFR-045; FD55GFV-73: 3 modes, step rate 6 ms (2D) or 3 ms (2DD/2HD), 1 kΩ terminator, power-on restore; PC-8801MR drive FD-55GFV-40-U "looks usable as an internal drive for the X1turbo Z and later".
- ↑ 5.0 5.1 5.2 X1turboZ CZ-880C 取扱説明書, page 79, "ディスクモードスイッチ": the initial disk drive setting at power-on is made by the DIP switch on the back; table of SW1, SW2, SW3, SW5 and SW6 against disk type numbers 0 to 7 (5-inch (3-inch) 2D 320 KB ×1; 5-inch (3-inch) 2DD 640 KB ×1; 5-inch 2HD 1 MB ×1; 5-inch 2HD 1 MB standard; 8-inch 2D 256 1 MB ×1; 8-inch 2D 256 1 MB standard; 8-inch 1S 128 240 KB standard; hard disk 10 MB ×1); with SW5 and SW6 on, the front start-up disk type switch takes priority and selects 2HD (×1) or 2D; with SW5 on and SW6 off it selects 2HD (×1) or 2DD; SW4 is set on at the factory and needs no setting; the computer is shipped set so that the front start-up disk type switch takes priority.
- ↑ X1turboZ CZ-880C 取扱説明書, page 65: optional interface boards connect to the expansion I/O ports in the optional device panel on the back, up to two boards; remove 2 screws to take off the connector panel, remove 2 screws to take the connector cover off the panel, insert the board component side up along the rails into the I/O port connector, refit the cover and panel; for a board with no rear connectors the cover need not be removed.
- ↑ 7.0 7.1 X1turboZ CZ-880C 取扱説明書, pages 87 and 88, specifications: clock built in, backed up by a built-in nickel-cadmium cell; keyboard separate, connected to the computer by a curl cord.
- ↑ 8.0 8.1 時計バックアップ用ニッカド電池, X1 Center—link(accessed 2026-10-21) The clock backup NiCd cell leaks and corrodes the board; on a CZ-870C (X1turbo III) sub board the vias under and beside the cell were black, and one track appeared broken; if backup is not needed, remove the cell or fit a 5.5 V supercapacitor.
- ↑ X1turboのよくある故障とその対処, シャープ博物館 (Sharp Museum)—link(accessed 2026-10-21) On the museum's X1turbo the rechargeable cell has been removed to prevent leakage.
- ↑ キーボードコネクタの半田剥離, X1 Center—link(accessed 2026-10-21) Keyboard connector solder cracks are a common fault on the X1, turbo and Z series; reflow the joints.
- ↑ X1/turbo用キーボードケーブルの劣化と交換, X1 Center—link(accessed 2026-10-21) The X1 and X1turbo keyboard cord sheath whitens and crumbles; the keyboard line carries +5.0 V.