IBM PCJr

 

 

Introduced in 1982 the pcjr was ibm's attempt to make some headway into the home market. It had some success but was overpriced compared to the apple II and the commodore 64. They keyboard that first shipped with the system was a large problem as it was a "chiclet" type. This meant the keys were little rubber rectangles so touch typing was nearly impossible. Ibm later offered a much better standard type keyboard which made typing much better. The problem was ibm waited too long and had to large of a backlog of orders for the new keyboard that by the time the started filling requests the pcjr was doomed. Sometime in late 1984 to early 1985 ibm discontinued the pcjr.

Processor Intel 8088 4.77mhz
Type of BUS pcjr sidecard bus (proprietary isa)
Memory (Min/Max) 64k/736k
Display CGA + 16 color pcjr mode
Announce date ~1983
List price 1.300 US$ (no monitor/printer)

Now for a look inside a pc jr. I don't have a modem card yet but once I get one I'll post a photo of it. Click on each photo for a full sizes version (caution some of them are over 300k)

Here is the system I'll tear down. No harm will come to this system :-)
Here is the inside. My system has the floppy option installed. Not every pcjr will have this. My system also has the 64k ram upgrade taking it to 128k. The cards going from left to right are power board / 64k memory upgrade / floppy controller. The empty socket between the memory upgrade and the floppy controller is for a modem card.
Here is a better look at the power supply board. It's odd it needs this as the jr comes with an external power adapter. The connectors on the left end are their to power the floppy drive.
Here is the 64k ram expansion card. Not much else to say about it.
Here is the floppy controller. It was designed to operate only one drive but a hack dose exist that allows the use of two drives. Both drives will turn on when a read/write is requested but only the correct drive will fully respond. I have not done this hack but have read success from several others.
Not much special here. just a standard floppy drive with a fan on the back. Still trying to figure out why they did not place the fan near the power board as it generates the most heat. Dose it really make since to drag all that heat over the entire system?
With the floppy drive on it's site you can see how it's attached to the system. Just simply gram the back and give a steady pull and it should come out.
With everything out we can see the entire mainboard. The 8088 processor is the long horizontal chip next to the sidecard bus to the right. The system rom is above the left cartridge port.
here is the label on the underside of the system. Gives basic information like model number and fcc information. As with nearly all ibm system this one was not made by ibm ("Manufactured for ibm" clearly visible in the upper left corner of the sticker(upper right of the photo)).