The Sharp PC-5000

Front Front side PC-5000 The Sharp PC5000 is a portable MS-DOS compatible machine. This means the hardware is not IBM-PC compatible, and it uses a special version of MS-DOS. 2.00 in this case. In the early days (1983) of the PC this was not uncommon. The screen is 640 x 80, giving it 80 characters wide by 8 lines.
The PC-5000 has its design faults: DO NOT try to move the display backwards when it is in position. From a special carton delivered with the machine:
  1. Close the cabinet completely.
  2. Open the cabinet to the full back position.
  3. Move the display forward to a comfortable viewing angle.
Obey this or you break some components with can block the mechanism. These broken components can be removed, but the display will feel very flimsy afterwards.
Another feature is the OFF key. It will not switch off the computer, but is for a sleep mode (which must be supported by software). The OFF.COM program (part of the DOS) however always works.

The availability of LCD screens which support 80x25 lines was the end of the PC5000 and similar machines. Complete IBM-PC compatibility also became the rule. An visitor of the site send me a first hand account of the PC5000 area.

Side view Side view PC-5000 The internal memory is 128 KByte, which can be extended with RAM cartridges like the CE-100M (64 KByte RAM) or CE-103M (128 KByte RAM). They contain dynamic RAM, so are volatile.
The cartridge slots also accepted ROM cartridges, like Extended Basic (64 KByte ROM) or EasyPac (CE-116M), a software suite consisting of EasyWrite II, EasyReport and EasyComm. The cartridges are places at slots at the bottom of the PC-5000. The 128 KByte CE-103M can only be installed at slot 1. A 64 KByte will work in both slots, but when combined with a CE-103M in slot 1, will have the switches set on CS:2 and MAP:A and must be placed in slot 2. If two CE-100M modules are used, one must have MAP set to A, the other to B. The CE-103M doesn't have switches. The EasyPac ROM module wants slot 1, BASIC ROM can be in both.
With disk unit PC-5000 with disk unit The Floppy Disk Unit contains both drives and disk controller board. The disk controller board contains a uP765 chip, the same as the IBM-PC. The system accepts standard 5 1/4 " 360 KByte MS-DOS floppies. The Drives are designated C: and D:, leaving A: for the Bubble Memory. Booting from the C: floppy is possible if no bubble is present.
Bubble memory PC-5000 bubble cartridge PC-5000 with bubble cartridge ejected PC-5000 with bubble cartrige inserted The bubble memory is one of the parts that make the PC-5000 special. Look here for more info on bubble technology or see the Functional Description from the Intel Component Data Catalog from 1981. Each bubble (adressed as drive A:) seems to contain a read-only bootable MS-DOS and 128 KByte storage capacity. The build in CHKDSK reports:
257024 bytes total disk space
 39936 bytes in 6 hidden files
 93184 bytes in 6 user files
123904 bytes available on disk
The user files are:COMMAND.COM, MODE.COM, OFF.COM, CHKDSK.COM, EDLIN.COM and BASICEXE.EXE. These files cannot be deleted.
The bubble modules contain apart from the bubble itself some passive components a Hitachi HA16635 IC (30 pins SMD). This could contain the MSDOS, but then one would expect a copyright on the case. So probably the MS-DOS is build into the PC-5000, just as BASIC, but will only boot if a bubble or a bootable MS-DOS present.
If neither is the case, you get the built-in demo (BASIC is also an option, but depends on the BASIC module being installed). The blurb below is part of this demo.

The ROMs contain this fine marketing blurb, which I want to share:



Managers and Professionals on the move.
Sharp PC-5000 Portable Computer helps people get the best out of themselves.
At the same time,they will get the best out of the PC-5000 with the realization
of a whole new concept--that of the mobile, personal electronic office.

All Inclusive.
Portability & communication is the ideal phrase to describe the Sharp PC-5000. 
In a small unit comes the fully ready-to-run display, keyboard with optional 
printer and modem.  Give the unit a heavy workload and a variety of tasks. 
With its large memory capacity--128K bytes of RAM expandable 256K--
it can do them all,Wherever and whenever you want it to.

All the Computing Power You Will Ever Need.
Portability and communications are the keys to keeping your personal computer
You can use the PC-5000 complete as a stand-alone,or connect it to a host computer
Use it as a word processor to develop or edit various reports or personal
letters.  Via a modem, you can plug your PC-5000
into the telephone and gain access to data bases anywhere,
renew your programs, and obtain current financial information.

Change the floppy drives to Flash, Kbytes to MBytes, modem to Wifi and it applies to modern laptops :-)

Some info on the power supply: 15 V DC / 600 mA. Pin is minus, barrel plus.

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Latest update: 2020-03-06