Sharp X68000 PRO
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| A black X68000 PRO-HD (bottom) with two Fujitsu FM Towns II machines stacked on it (photo: htomari, CC BY-SA 2.0) | |
| Specifications | |
|---|---|
| Manufacturer | Sharp |
| Type | Personal computer |
| Released | March 1989 (PRO); April 1990 (PRO II)[1] |
| Intro price | ¥298,000 (PRO); ¥285,000 (PRO II)[2] |
| CPU | 68000 at 10 MHz[1] |
| Memory | 1 MB[1] |
| Storage | Two 5.25-inch floppy drives; 40 MB SASI hard disk in the -HD models[1] |
| Display | — |
| Sound | — |
| Power | 100 V AC[3] |
| OS / Firmware | — |
| Model no. | CZ-652C, CZ-662C (PRO, PRO-HD); CZ-653C, CZ-663C (PRO II, PRO II-HD) |
The Sharp X68000 PRO (CZ-652C) is the desktop version of the Sharp X68000, sold in Japan from March 1989 alongside the twin-tower Sharp X68000 EXPERT. It was the first X68000 in a horizontal case. It has four I/O expansion slots, 1 MB of memory as standard and its own keyboard and mouse, and the PRO-HD (CZ-662C) adds a 40 MB hard disk.[1][2] The PRO II (CZ-653C) and PRO II-HD (CZ-663C) followed in April 1990.[1]
The PRO and the PRO II have different power supplies. The PRO's is a boxed unit, Sharp part UADP-0070CEZZ, which owners call the PRO-BOX. The PRO II has a supply called the SH5, laid out like the supplies of the tower models.[4][5][3] Sharp's reissued X68000 service manuals cover only the XVI, so no diagram of either supply is publicly available, and most repair information comes from owners.[6]
History
[edit | edit source]The PRO and PRO-HD went on sale in March 1989 at ¥298,000 and ¥408,000, in grey or black, and the PRO-HD set won a Good Design Award that year. The PRO II and PRO II-HD followed in April 1990 at ¥285,000 and ¥395,000.[1][2] Sharp sold the PRO line alongside the towers because the tower design had given up expansion room and access to the inside for its looks. The PRO was cheaper and had more slots, but its circuits differ in places from the towers, and some add-on hardware, such as the Mach-2 SCSI board, was listed as not supported.[2] Pioneer sold the PRO under its own name, mainly as a controller for telephone message services.[2]
Hardware
[edit | edit source]Case and controls
[edit | edit source]The PRO's front panel carries the two 5.25-inch drives with their EJECT buttons, the HD BUSY, TIMER and POWER lamps, and along the bottom edge the reset and interrupt buttons, volume control, headphone socket, two joystick ports, mouse socket and power switch.[7] The towers have one joystick port at the front and one at the rear; the PRO series has both at the front.[2] There is no main power switch on the rear, which every tower model has, and no stereoscopic terminal, which the towers from the original to the XVI have.[2] The 68000 processor sits in a socket.[2]
Boards
[edit | edit source]| Part | PRO (CZ-652C, CZ-662C) | PRO II (CZ-653C, CZ-663C) |
|---|---|---|
| Power supply | PRO-BOX | SH5 |
| Main board (large) | K6835DE | X6835CE |
| Main board (small) | K6836DE | K6836DE |
| Expansion slot board | Not listed | X6839DE |
| Interface board | Not listed | K6837DE |
| POWER lamp board | Not listed | S6838CE |
| Backup cell | Not listed | Sony CR2450 |
| Floppy drives | TEAC FD-55GFR | TEAC FD-55GFR |
| Keyboard | DSETK0020CE00 (grey), DSETK0020CE01 (black) | DSETK0024CE01 (grey, CSA-71384), DSETK0024CE00 (black, CSA-71284) |
[5] Both keyboards have white-stemmed key switches.[5]
Power supply
[edit | edit source]The PRO's supply, UADP-0070CEZZ, runs only from Japanese 100 V mains. It keeps a +5 V standby rail live whenever it is plugged in and starts its main outputs on a power-on signal from the computer, which is how the front switch and the software timer turn the machine on.[3][2] Poe notes two production versions: machines with a three- or four-digit serial number and machines with a five-digit one, whose supplies differ in some capacitors and resistors. The board is paper-based epoxy with thin copper, so take care when desoldering, and leave its trimmer alone.[5]
The PRO II's SH5 has the same physical layout as the "Tetris-piece" supply of the tower models, and its wiring colours differ from theirs.[3] Poe gives R5 as 0.33 Ω and R36 as 220 Ω, and notes that some have a heatsink on IC23.[5] Fram, who repairs X68000 supplies, counts the PRO II among the machines with the SH4, while Poe and kunichiko list its supply separately as the SH5.[8][4] Kunichiko has published in-circuit resistance readings taken from a working SH5.[4]
Floppy drives
[edit | edit source]The PRO and PRO II use TEAC FD-55GFR drives (TEAC part 19307350-60) in a Sharp mounting, CMECF0015CE01. The tower models from the ACE to the X68030 use a different drive.[5] Poe lists the electrolytic capacitors on the drive's three boards; see the capacitor guide.
Memory and settings
[edit | edit source]Like the original X68000 and the ACE, the PRO and PRO II have 1 MB as standard; the EXPERT and later towers have 2 MB.[2] Sharp's 1 MB expansion boards for them are the CZ-6BE1A and CZ-6BE1B, which also fit the ACE.[2] The 16 KB SRAM that holds the memory switch settings is write-protected in normal use, but on the PRO-series machines a design problem around the SRAM can corrupt its contents even in normal use.[2] Sharp's CZ-6EB1 expansion I/O box does not work with the PRO or PRO II.[2]
Known problems
[edit | edit source]- Corrupted SRAM settings, from the design problem described above.[2] See the Troubleshooting Guide.
- Supply failures. On kunichiko's PRO II the SH5's Q31 and Q32 had shorted and the fuse had blown.[4]
- Corroded supply wiring: leaded-solder found the original harness of a PRO's supply corroded and advises replacing any wire that has turned green or brittle.[3]
Repair guides
[edit | edit source]- Sharp X68000 PRO General Maintenance
- Sharp X68000 PRO Troubleshooting Guide
- Sharp X68000 PRO Capacitor Replacement Guide
Related pages
[edit | edit source]References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 X68000, IPSJ Computer Museum, Information Processing Society of Japan—link(accessed 2026-10-21) Series table: X68000 PRO, CZ-652C, and PRO-HD, CZ-662C, listed with the March 1989 models, 1 MB, 40 MB hard disk in the PRO-HD; PRO II, CZ-653C, and PRO II-HD, CZ-663C, April 1990, 1 MB, 40 MB hard disk; 68000 at 10 MHz and 5.25-inch drives for every model up to the SUPER; hard disk interface SASI until the SUPER-HD (June 1990) introduced SCSI.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 X68000, Wikipedia (Japanese)—link(accessed 2026-10-21) Model table: PRO CZ-652C ¥298,000 and PRO-HD CZ-662C ¥408,000 (40 MB), grey or black (-GY/-BK), horizontal case, 1 MB; the first horizontal model, four expansion I/O slots, PRO keyboard and mouse; the CZ-662C set won a 1989 Good Design Award; Pioneer sold an OEM version with a Pioneer logo, used mainly for controlling telephone message services. PRO II CZ-653C ¥285,000 and PRO II-HD CZ-663C ¥395,000 (40 MB), April 1990, grey or black, horizontal, 1 MB. Text: the PRO series was sold alongside the towers because the tower design had given up expandability and access to the inside; it was cheaper and had more slots, but its circuit design differs in places from the towers and some hardware, such as the Mach-2 SCSI board, was not supported; the PRO series has two joystick ports on the front where the towers have one front and one rear; the original, ACE, PRO and PRO II have 1 MB as standard, the other models 2 MB; the rear main power switch is absent on the Compact, PRO and PRO II; the stereoscopic terminal is fitted from the original model to the XVI, except on the PRO; the PRO-series machines have a design problem around the SRAM that can corrupt its contents in normal use; the CZ-6EB1 expansion I/O box does not support the PRO or PRO II; the MPU is in a socket on every model except the Compact; 1 MB RAM boards CZ-6BE1A, CZ-6BE1B and CZ-6BE1B(A) for the CZ-601C, 611C, 652C, 653C, 662C and 663C.
- ↑ 3.0 3.1 3.2 3.3 3.4 x68000-pro-picopsu– leaded-solder, 2021—link(accessed 2026-10-21) README: replacement board for the PRO (CZ-652C) supply, UADP-0070CEZZ, using a PicoPSU and a separate 12 V supply and handling the X68000's soft power-on; the original supports only Japanese 100 V; not for the PRO2 (CZ-653C), whose supply has a completely different layout identical to the tower machines' "Tetris-piece" supply; the wiring colours also differ between PRO2 and tower models; the original harness is often corroded, and green or crunchy wire should be replaced; wiring on the author's PRO: orange +5 V standby, red +5 V, blue −12 V, black ground, yellow +12 V, brown power-on; pressing the front power button starts the supply.
- ↑ 4.0 4.1 4.2 4.3 X68000シリーズ電源のハンダ面から見た抵抗配置図– Kunihiko Ohnaka (kunichiko), 2020-10-10—link(accessed 2026-10-21) Supply by model, quoted from Poe: PRO and PRO-HD (CZ-652C, CZ-662C) PRO-BOX; PRO II and PRO II-HD (CZ-653C, CZ-663C) SH5. In-circuit resistance maps measured on the author's own SH3, SH4 and SH5 (from a PRO II). SH5 repair on a PRO II: burnt area around ZD31; Q31 and Q32 found shorted, and the fuse had blown.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 SHARP X68000 修理– Poe—link(accessed 2026-10-21) Parts of the PRO (CZ-652C, CZ-662C): main board (large) K6835DE, main board (small) K6836DE; slot, interface and lamp boards not filled in. Parts of the PRO II (CZ-653C, CZ-663C): main board (large) X6835CE, main board (small) K6836DE, expansion slot X6839DE, interface board K6837DE, POWER lamp S6838CE, Sony CR2450 cell. PRO and PRO II floppy drive TEAC FD-55GFR 060, part 19307350-60, Sharp mounting CMECF0015CE01; the ACE to X68030 drive is a separate type, CMECF0013CE01. Power supply table: PRO "PRO-BOX", early (serial number of three or four digits) and late (five digits) versions differ in some capacitors and resistors, paper-epoxy board with thin copper, take care, do not turn the VR; PRO II SH5, R5 0.33 Ω, R36 220 Ω, some with a heatsink on IC23. Keyboards: PRO DSETK0020CE00 (GY) and CE01 (BK); PRO II DSETK0024CE01 (GY, CSA-71384) and CE00 (BK, CSA-71284); white-stem switches.
- ↑ 復刻サービスマニュアルX68000, Sharp, COCORO BOOKS—link(accessed 2026-10-21) The series holds one title, the service manual for the X68000 CZ-634C/CZ-644C (XVI), priced at ¥0.
- ↑ File:Sharp X68000 PRO-HD with FM Towns II (htomari).jpg, photograph of a PRO-HD by htomari, 19 September 2010, Wikimedia Commons, CC BY-SA 2.0. The front panel labels read EJECT, HD BUSY, TIMER, POWER, RESET, INTERRUPT, VOLUME, PHONES, JOY STICK 1 and 2, and MOUSE.
- ↑ 【訂正】X68kの電源ユニットのシルク印刷に間違いがあった件&X68kの電源修理再び(未完)3– Fram, 2024-03-24—link(accessed 2026-10-21) "The SH4 seems to be fitted to the EXPERT to the XVI and to the PRO II"; Fram has not seen the supplies of the original PRO, the SH2, SH3, X68030 or Compact.