IBM PS/2 Model 55SX


This is the same in size and appearance as the model 30 apart from the power switch is white on this and orange on the model 30. This one works but it has one major problem, at some time it has had something pushed into the floppy disk drive and now there are no heads left just the mounting plates. Unfortunately the floppy drive is the type that is only connected by a 34 pin ribbon and no power cable so I have not got a replacement one for it, I did consider swapping the heads from another one but this has got a single ribbon from the heads and all the others that I have got have two. This might be a good opportunity to try direct cable connection file transfer in case I need to add any files to it say to set up a printer or what ever.

The hard disk is an IBM WD-380S 80MB 3.5" which connects with a 72 cable ribbon with card edge connectors at each end. This is an ESDI ( Enhanced Small Device Interface ) type hard disk. The ESDI type controller was created in 1983 by the Maxtor Corporation in the USA

This also has an MCA Trantor systems SCSI host adapter fitted this has a 50 pin internal connector and a 25 pin D type external connector, it seems as though it probably had an external CD-ROM fitted at some time as it looks for it every time it boots up.

This is the riser, the motherboard connector is along the bottom edge, the connector along the top is for the hard drive, then there are 3 x 16 bit Micro Channel slots (MCA) the bottom on is longer as it incorporates the video extension interface that allows the addition of an advanced video graphics board such as the IBM 8514/A in order to upgrade video function without duplicating the built-in VGA circuitry. On the right side is the black block is the connector for the speaker.



IBM PS/2 55SX Type 8555

Motherboard Bar code no. 55X36194KFT 92F0623 155  
CPU Intel NG80386SX - 16    
3968 KB RAM 1 x 72 pin SIMM 68X6343 B 82F8221 053
Dallas Clock chip DS1287  
Riser 64F0809/EC01646/1102 B/C 55 X08 119097  
FDD 3.5" 1.44MB Alps DFP723D30A Bar Code L1P 70081571
34-pin connector & no power lead P/N 72X6112 EC NO.844421
HDD IBM 80MB Model No. WD - 380S Bar Code B1RM4121625
P/N 79F4013 MLC C81004 FRU 56F8892
Connected with a 72 pin PCB connector cable
Power supply Model no. AA15992 90W max.
IBM P/N 33F8138 GBM No 27F4920 EC No.C01278


1 Card Trantor systems Ltd.
SCSI Host adapter card with 1 internal & 1 external port.

Operating system
Windows 3.1
MS Word 2.0



Please e-mail me if you have further information or any criticism of the details shown



Last Updated 13th September 2002