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---
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.