--- title: IBM PC Junior categories: - Computers types: - Home Computer origins: - U.S.A. years: - '1983' cpus: - Intel 8088 params: name: PC Junior image: /media/museum/photos/ibm_pcjr_system_1.jpg company: /companies/ibm company_name: IBM specs: - label: NAME value: PC Junior - label: MANUFACTURER value: IBM - label: TYPE value: Home Computer - label: ORIGIN value: U.S.A. - label: YEAR value: November 1983 - label: END OF PRODUCTION value: March 1985 - label: KEYBOARD value: Chicklet keyboard (full stroke keyboard was available later) - label: CPU value: Intel 8088 - label: SPEED value: 4.77 MHz - label: CO-PROCESSOR value: Texas Instrument sn76496 n (sound) - label: RAM value: |- 64k (up to 640 KB)\ Extended model : 128k - label: VRAM value: from 2k to 128k (use the conventional RAM) - label: ROM value: 24 KB - label: TEXT MODES value: 40 x 25 / 80 x 25 - label: GRAPHIC MODES value: 160 x 200 (16 colors), 320 x 200, 640 x 200 - label: COLORS value: '16' - label: SOUND value: three channels - label: SIZE / WEIGHT value: Unknown - label: I/O PORTS value: 2 cartridges ports (64 KB each), Centronics (optional), RS232, Joystick, Light Pen, video out (RCA plug) - label: BUILT IN MEDIA value: one 5.25'' disk drive - label: OS value: MS DOS - label: POWER SUPPLY value: External PSU - label: PRICE value: Unknown tabs: - photos - adverts - hardware - software - links - docs forum_thread: 196 photos: - title: IBM PCJR IN ALL ITS GLORY subtitle: '' text: Picture courtesy of Verault ebay seller image: /media/museum/photos/ibm_pcjr_allglory_1.jpg - title: MAIN UNIT subtitle: '' text: '' image: /media/museum/photos/ibm_pcjr_system_s3.jpg - title: COMPLETE SYSTEM subtitle: '' text: Complete system with its massive AC adaptor and a monochrome composite monitor. image: /media/museum/photos/ibm_pcjr_withmonitor_s1.jpg - title: PRO VERSION subtitle: '' text: This model is equipped with a PC professionnal keyboard, a second disk-drive unit on top of the computer, and a RAM expansion plugged to the right of the case. image: /media/museum/photos/ibm_pcjr_4.jpg - title: SIDES subtitle: '' text: On the right side, the JrCaptain sidecar expansion provided 128 KB RAM expansion, a standard Parallel printer interface and a real time clock. image: /media/museum/photos/ibm_pcjr_sides_s1.jpg - title: PCJR COLOR MONITOR subtitle: '' text: Thanks to **Edwin Amsler** image: /media/museum/photos/ibm_pcjr_colmonitor_s1.jpg - title: ORIGINAL CHICKLET KEYBOARD subtitle: '' text: '' image: /media/museum/photos/ibm_pcjr_keyboardbox_1.jpg - title: 'SECOND KEYBOARD #1' subtitle: '' text: Below the typewriter keys, this second version also used a rubber membran. image: /media/museum/photos/ibm_pcjr_keyboard_s1.jpg - title: 'SECOND KEYBOARD #2' subtitle: '' text: The keyboard could be either connected to the main unit by a standard cord, or used without cord, from a distance up to 6 meters, thanks to its dual infrared LEDs. image: /media/museum/photos/ibm_pcjr_keyboard_s2.jpg - title: REAR SIDE subtitle: '' text: |- **(1)** Parallel connector from the JrCaptain sidecar expansion\ **(2-3)** Joystick connectors\ **(4)** Printer connector\ **(5)** Keyboard connector\ **(6)** Light pen connector\ **(7)** TV set connector\ **(8)** Conposite video output jack\ **(9)** Optional modem hole\ **(10)** IBM Colour monitor connector\ **(11)** Serial connector\ **(12)** Tape recorder connector\ **(13)** Power connector and switch\ **(14)** External audio jack. image: /media/museum/photos/ibm_pcjr_rearside_s1.jpg - title: OPENED subtitle: '' text: |- **(1)** Power supply card\ **(2)** 128 KB expansion card\ **(3)** Floppy drive controller card\ **(4)** Infrared receiver. image: /media/museum/photos/ibm_pcjr_inside_s1.jpg - title: 'MOTHERBOARD #1' subtitle: '' text: |- **(1)** Buzzer\ **(2)** Tape recorder remote control relay\ **(3)** Various I/O chips from Intel, AMD and NEC\ **(4)** Motorola 6845 display controller\ **(5)** Custom IBM memory management chip\ **(6)** Power card connector\ **(7)** Memory expansion connector\ **(8)** 64 KB RAM chips (8 x 4164)\ **(9)** Infrared receiver\ **(10)** Modem card (left) and FDD controller card connectors\ **(11)** 24 KB ROMs, hold the Cassette BASIC interpreter\ **(12)** ROM cartridges connectors\ **(13)** Bus expansion connector\ **(14)** Intel 8088 microprocessor. image: /media/museum/photos/ibm_pcjr_mainboard_s1.jpg - title: 'MOTHERBOARD #2' subtitle: '' text: Close-up view of the infrared receiver and dual cartridge connectors. image: /media/museum/photos/ibm_pcjr_mainboard_s2.jpg - title: PCJR MANUALS subtitle: '' text: '' image: /media/museum/photos/ibm_pcjr_manuals_s1.jpg - title: SAMPLER DISKETTE subtitle: '' text: |- Cover of the Sampler diskette.\ Typical pictures of the personal computer use of the time: Business, home, school, for people of all ages. image: /media/museum/photos/ibm_pcjr_samplerdisk_s1.jpg adverts: - title: 'ADVERT #1' subtitle: '' text: '' image: /media/museum/pubs/ibm_pcjr_pub_1.jpg hardware: - title: ADAPTER CABLE FOR SERIAL DEVICES subtitle: '' text: This IBM PC jr option allows many serial devices to be connected, such as printers and external modems. image: /media/museum/hardware/ibm_pcjr_serialadaptbox_1.jpg - title: ADAPTER CABLE FOR THE IBM COLOR DISPLAY subtitle: '' text: This IBM PC jr option allows you to attach the IBM Personal Computer Color Display to the IBM Pc jr system unit. image: /media/museum/hardware/ibm_pcjr_color-display-cable_box_1.jpg - title: BASIC CARTRIDGE subtitle: '' text: Thanks to **Edwin Amsler** image: /media/museum/hardware/ibm_pcjr_basiccart_s1.jpg - title: 64K RAM EXPANSION subtitle: '' text: This add-on doubles the existing RAM of the PC Jr. System and provides 80 Column text support. image: /media/museum/hardware/ibm_pc-jr_64k.jpg - title: 128K RAM ''SIDE-CAR'' EXPANNSION subtitle: '' text: The expansion is plugged on the right side of the main-unit. Several expansions could be plugged to each other like this. image: /media/museum/hardware/ibm_pcjr_128k_extension.jpg - title: 3 SIDE-CAR EXPANSIONS subtitle: '' text: Here there are 3 side-car extensions plugged into each other on the right side of the main unit (2 128k RAM extensions and 1 printer interface). image: /media/museum/hardware/ibm_pcjr_triple_extension.jpg - title: PARALLEL PRINTER ATTACHMENT subtitle: '' text: This unit is used to use any parallel printer with a PC Junior. It plugs onto the right-hand side of the computer. image: /media/museum/hardware/ibm_pcjr_parallel-printer-attachment_1.jpg - title: JOYSTICK subtitle: '' text: This joytsick is only compatible with the PC Junior image: /media/museum/hardware/ibm_pc_junior_joystick.jpg - title: JOYSTICK BOX subtitle: '' text: '' image: /media/museum/hardware/ibm_pcjr_joystick-box_1.jpg - title: JOYSTICK PINOUTS subtitle: '' text: |- 1 - +5v DC\ 2 - Res. Y-Axis\ 3 - Logic ground\ 4 - Key\ 5 - Fire button\ 6 - Fire button\ 7 - Res. X-Axis\ 8 - Shield ground image: /media/museum/hardware/ibm_pcjunior_joystick_pinout.gif - title: COMPACT THERMAL PRINTER subtitle: Model 5181 text: '' image: /media/museum/hardware/ibm_pcjr_compact-thermal-printer_1.jpg screenshots: - title: CROSSFIRE subtitle: cartridge label text: '' image: /media/museum/software/ibm_pcjr_crossfire-cart.jpg - title: MINESHAFT subtitle: cartridge label text: '' image: /media/museum/software/ibm_pcjr_mineshaft-cartridge_1.jpg - title: KING'S QUEST subtitle: cartridge label text: Thanks to James R. Skinner for this picture image: /media/museum/software/ibm_pcjunior_kingsquest.jpg links: - title: Forever70...80...90... url: http://perso.wanadoo.fr/fabrice.montupet/ibm.htm text: Nice page about the PC junior (french) - title: Mike's PCjr Page url: http://mail.magnaspeed.net/~mbbrutman/PCjr/pcjr.html text: Too much things in there to lis them all. Go & visit! - title: PC Jr Reborn! url: http://www.micro-zone.com text: Forums, Software, News, Links and more - title: PCjr.org url: http://www.pcjr.org/ text: Very complete site, worth a visit docs: - title: GUIDE TO OPERATIONS url: null cover: /media/museum/docs/couvs/ibm_pc-jr_guide-to-operations.jpg text: |- **GUIDE TO OPERATIONS**\ written by IBM  compiled/archived by Eric Bylenga\  type of document : PDF\  source : www.old-computers.com oc_id: 186 source: url: https://web.archive.org/web/20230130041031/http://www.old-computers.com/museum/computer.asp?c=186 date: '2023-01-30' --- After launching the [IBM PC](/museum/ibm-pc-model-5150/) (and its great success), IBM tried to stand out a standard for home computers, it created then the PC junior, which itself is a "light" version of the PC especially designed for home activities. Despite its qualities, the PC jr had few success and never managed to replace the established home computers like [Commodore 64](/museum/commodore-c64/), [Apple II](/museum/apple-ii/) or [Atari 800](/museum/atari-400/). Two IBM PC junior models were available: a basic one and a enhanced one (supplied with 128k, 30 programs, a 5.25" floppy disk drive \[360 KB\] and its controller). Contrary to the IBM PC, the power supply is not integrated to the case, but is external. The keyboard is linked by infra-red to the CPU, though there was a RJ11 (standard phone jack) plug that could be used instead to save batteries. It is impossible to connect a 8087 math co-processor. The RS232 connector is not a standard one. To use a standard RS232 device, the user has to buy a special adapter ("Berg" style connector breakout -> D25 connector). The PC Jr runs under MSDOS 2.1 (the same version as the PC) and handles a hard disk when it is not possible to connect hard disk on the PC Jr (go figure)! There was an internal modem available that ran at 300 bps sold by IBM. Third party modems were also available at 1200bps. A cartridge containing enhanced basic (with special graphics instructions) was also available. To get a 80 column text display, the extra 64k RAM expansion is needed. Many IBM PC programs would not originally run on the PCjr because it did not include a DMA controller. This was available through a memory side-car add-on from Tecmar Systems. Many people were able to then run the PCjr as a competent business type of system as well.