Sharp X1D Troubleshooting Guide
The Sharp X1D (CZ-802C) has no BASIC in ROM. At power-on its IPL program looks for something to boot, and the IPL menu on the screen is the first sign that the main board is working.[1]
Normal start-up
[edit | edit source]An X1D in working order behaves like this at power-on, according to an owner who tested one bought untested at auction:[2]
- The power indicator lights and the floppy drive light comes on.
- The drive light goes out when the drive finds no disk.
- With no bootable disk, ROM board or tape, the IPL menu appears: "Make ready any device", then F (floppy), R (ROM), C (cassette) or T (timer).[2][1]
- Pressing T opens the TV timer editor; once a timer is saved, the timer indicator on the main unit lights.[2]
Symptom table
[edit | edit source]| Symptom | Probable cause | Action |
|---|---|---|
| No indicators at all | No mains, switch off, or power supply fault | Check the mains lead and the AC 100 V supply. The X1D draws 49 W.[3] See Sharp X1D Capacitor Replacement Guide. |
| Power light on, drive light never comes on, no picture | Main board not starting, or power supply output low | Measure the supply outputs; look for corrosion near the NiCd cell.[4] |
| Drive light on, no picture | Monitor not in digital RGB mode, or RGB cable | The X1D has digital RGB output only; try another RGB monitor and cable.[3] |
| IPL menu appears, keys do nothing | Keyboard cord, keyboard jack or keyboard fault | See Keyboard faults. |
| Clock and timer lose their settings | NiCd cell flat, removed or leaking | Inspect the cell and the board around it; see General Maintenance. |
| Disk does not boot, drive light stays on or the head moves | Dirty head, a disk written on a different drive, or a drive fault | Clean the head; try a known-good disk; see Floppy faults. |
| Colours wrong in some games | The X1D's palette port differs from later X1s | Not a fault. Many titles, Manhattan Requiem among them, show wrong colours on an X1D.[1] |
| Software fails from an added 5¼-inch drive | The X1D's floppy interface differs from later X1s | Not a fault. Hydlide II is one title that does not run this way.[1] |
| CZ-8RL1 data recorder will not wind, rewind or cue | The X1D cannot control the CZ-8RL1 | Not a fault. See Cassette. |
| Program freezes after pressing reset | The X1D has only an NMI reset; software not written for it can freeze | Switch off and on to restart.[1] |
Keyboard faults
[edit | edit source]The keyboard sends key codes to the computer one way over a single wire. Its plug is a 3.5 mm stereo plug with +5 V on the tip, the data signal on the ring and ground on the sleeve.[5][6]
- With the computer on and the keyboard unplugged, measure between the tip and sleeve contacts of the jack. Expect +5 V.[5]
- Look over the coiled cord. One X1D owner found the cable frayed and unreliable, and X1 Center reports the sheath of X1 keyboard cords crumbling with age.[2][7]
- If keys work only when the plug is pushed one way, reflow the jack's joints on its board.[8]
- With +5 V present and the cord sound, watch the ring line on an oscilloscope while pressing a key. No pulses point to the keyboard; pulses with no response point to the computer.[5]
The keyboard cannot report several ordinary keys held together; only Shift and similar keys combine with others. This is normal on an X1.[1]
Floppy faults
[edit | edit source]The internal MSHD200A01 is a 3-inch double-sided double-density drive storing 320 KB per disk, and it does not restore its head to track 0 at power-on.[9][3] The floppy controller is an 8877A, and the X1D separates the data with a discrete phase-locked loop built from TTL; later models use a single VFO chip.[3][9][10]
- If no disk boots, clean the head and try a disk known to have been written on another X1D or an X1 3-inch drive.
- The internal drive's connector is soldered to the main board, so check the joints there if the drive does not respond at all.[9]
- An HxC floppy emulator works with the X1D and can stand in for the drive while it is being repaired, or rule the drive out.[2]
- More drive procedures are in Floppy Drive Repair.
Cassette
[edit | edit source]The X1D has no tape deck of its own. Its BASIC manual describes the CMT command as remote on and off for an external recorder, and lists no tape sensor function.[11] Sharp's CZ-8RL1 data recorder can be plugged in, but the X1D cannot control its fast wind, rewind or cueing.[1] Iwai Ippei traced the reason: the X1D's sub-CPU is a different version from the X1turbo's and X1F Model 20's, and on the X1D board the deck control outputs are left unconnected while the deck status inputs to the 8255 are held at +5 V.[12] A CZ-8RL1 that will not wind under program control on an X1D is therefore working normally.
Power and battery
[edit | edit source]Sharp rated the X1D at 49 W from AC 100 V.[3] No circuit of its power supply has been published. A NiCd cell backs up the clock; when it leaks it corrodes the board around it, and X1 Center has seen blackened plated holes and broken tracks next to these cells on other X1 boards.[4]
Related pages
[edit | edit source]- Sharp X1D
- Sharp X1D General Maintenance
- Sharp X1D Capacitor Replacement Guide
- Sharp X1 Troubleshooting Guide, for the first X1 model
- Battery Explosion, Capacitor or Corrosion Damage
- Floppy Drive Repair
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 X1 (コンピュータ), Japanese Wikipedia—link(accessed 2026-10-21) The X1 has no system program in ROM; at power-on the IPL tries the FDD, an expansion ROM board and the CMT in turn, and if none answers, or the user cancels, it shows a menu of the three boot devices and the TV timer editor. X1D: the later data recorder cannot be controlled from it; its floppy interface differs, so some software (Hydlide II) fails with an added 5¼-inch drive; its palette port differs, so many titles (Manhattan Requiem) show wrong colours. Before the X1turbo, X1 models had only an NMI reset button, which jumps to 0066h and can freeze software not written for it. Separate keyboards use a 3-pole 3.5 mm plug; key presses other than Shift and similar keys cannot be detected together.
- ↑ 2.0 2.1 2.2 2.3 2.4 Sharp X1 D, Japanese Vintage Computer Collection (hachibitto.com)—link(accessed 2026-10-21) At power-on the power indicator and the floppy drive light came on, and the drive light went out quickly when it found no disk; with the keyboard and digital RGB monitor connected, the IPL screen appeared and the timer programmer worked; after saving a timer the timer indicator on the main unit lit; the keyboard cable was frayed; BASIC and a game loaded from an HxC floppy emulator.
- ↑ 3.0 3.1 3.2 3.3 3.4 Oh!MZ, November 1983, p. 26, Table 1, "パーソナルコンピュータ(CZ-801C/802C)仕様": 8877A floppy controller; compact floppy drive double-sided double-density, 80 tracks, 320 KB formatted, 3-inch disks; R, G, B separate video output; AC 100 V ±10 %, 50/60 Hz; 49 W (X1D); the X1D also has an interface for the 5¼-inch CZ-800F and a cassette recorder. Scan on the Internet Archive, item oh-mz-1983-08-12, file Oh!MZ_1983-11.
- ↑ 4.0 4.1 時計バックアップ用ニッカド電池, X1 Center—link(accessed 2026-10-21) NiCd clock backup cells leak electrolyte and gas; the liquid soaks through plated holes and dissolves the copper, and tracks break; photographs of a CZ-800C main board with blackened holes near the cell and of an X1turbo III sub-board with black vias and a broken track under the cell.
- ↑ 5.0 5.1 5.2 佐藤 達之 (Sato Tatsuyuki), SHARP X1/X1Turbo キーボード端子 通信仕様 Ver 0.1, 2001, X1 Center, x1kbd.pdf, p. 1: one-wire serial from keyboard to main unit only, in a format like an infrared remote control (an idle high line, a low header, then data bits distinguished by the spacing of low pulses); 3.5 mm stereo mini jack with +5 V on the tip, the transmit signal on the ring and ground on the sleeve.
- ↑ 祝一平 (Iwai Ippei), 試験に出るX1 ハードウェアのフルコース (Nihon SoftBank, 1987), p. 78: the keyboard contains an 80C48 that sends key data serially, one way, to the 80C49 in the main unit, which links the Z80 with the keyboard, cassette deck and µPD1990 clock. Scan on the Internet Archive, item SHARPX1TecRef.
- ↑ 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 coiled cord of X1 and X1turbo keyboards whitens and its sheath crumbles; the cord carries +5.0 V, so a short is dangerous.
- ↑ キーボードコネクタの半田剥離, X1 Center—link(accessed 2026-10-21) Keyboard connector faults are frequent on X1, turbo and Z machines; a keyboard that works only when the plug is pushed one way has a cracked joint on the connector board.
- ↑ 9.0 9.1 9.2 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) X1D floppy interface: no DMA, 2HD or FM; discrete TTL VFO; 150 Ω terminators on the external connector; internal drive connector soldered to the board, so the cable cannot be changed. MSHD200A01: 3-inch 2D, 820 Ω terminator, no restore at power-on.
- ↑ 搭載チップセット, X1 Center—link(accessed 2026-10-21) Floppy VFO: discrete on the CZ-802C (X1D); MB4107 on the X1F Model 20. X1D backup battery 2.4 V 30 mAh.
- ↑ 祝一平, 試験に出るX1 (Nihon SoftBank, 1987), p. 89: in the X1D's BASIC manual the CMT command is remote on/off for an external tape deck, and there is nothing for the cassette sensor command. Scan on the Internet Archive, item SHARPX1TecRef.
- ↑ 祝一平 (Iwai Ippei), "X1DにCZ-8RL1をつないでしまう", Oh!MZ, December 1985, pp. 54-55: only the sub-CPUs of the X1turbo and X1F Model 20 can drive the CZ-8RL1 with full logic; the X1D's sub-CPU is different; on the X1D the signals to the deck (such as FAST) float and the signals from it (such as APSS, on an 8255 pin) are fixed at +5 V. Scan on the Internet Archive, item oh-mz-1985, file Oh!MZ_1985-12.