IBM Thinkpad 390 Series Information & Upgrading
***  This Page is a work in progress ***

Welcome to my information pages for the IBM Thinkpad 390 Series pages.  In searching for information on usage and upgrading the IBM Thinkpad 390 series on the web I became quite disappointed on what I found available about these laptops on the web.  I'm sure others have ran into the same problem as I have so I've decided to start a page to help fill this missing gap.

General information on the Thinkpad 390 Series

Thinkpad 390

The Thinkpad 390 was the first model introduced in the series.  Available with a Pentium 233MMX or Pentium II 233 & 266mhz CPU's.  Utilizes MMC1 CPU Modules and is not easilly upgraded past 266mhz. 

Thinkpad 390E

The 390E built on the 390 by adding new processors (PII300 & 333mhz, & Celeron 366mhz) and adding a S-video out port.  The 390E utilizes MMC2 CPU Modules.  Base memory on many models of 390E came with 64mb of ram and were upgradable to 256mb.  Hard drives as large as 6.4gb were available as well as a DVD Drive.  3 LCD Displays were available.  12.1", 13.3" & 14.1"

Thinkpad 390X

The Thinkpad 390X Series came in many configurations.  The following processors are available on the 390X.  Pentium II 400mhz, Celeron 400mhz, or Pentium III 450 & 500mhz.  Base memory was 64mb upgradable to 512mb.  3 LCD Displays were available.  12.1", 14.1", & 15".    Hard disk drives up to 12.1gb were available as well as a DVD Drive. 

Upgrading the 390 series

    Upgrading the Hard Disk Drive
    Upgrading the CD Rom Drive
    Upgrading the Memory
    Upgrading the Processor
    Connecting a TV to the 390E & 390X  using the SVideo out Port

Upgrading the Hard Disk Drive

Upgrading the Hard disk drive is one of the easier upgrades to do on these laptops.  I've personally tested Hard Drives as big as 40gb on the 390E & 390X with no problems.  I'd like to test an 80gb, but don't have access to one at this time.  To make the upgrade process go as smooth as possible it is very important to upgrade the BIOS to the latest revison before doing anything else.  Once the BIOS is upgraded power down the laptop and on the backside is a large blade screw.  Loosen this screw to remove the cover and gain access to the HDD caddy.  Once the cover is removed on the Caddy should be a black fabric handle.  Pull on this handle to remove the caddy from the laptop.  The cover just snaps off the caddy to gain access to the hard disk.  With the cover off the caddy remove the hdd, transfer the hdd connector to the new drive.  Installation is the reverse of removal.  I did not try to partion the drive using Windows 98.  I went ahead and upgraded to Win2K Pro and the full size of the drive was available during the setup process.

Upgrading the CD Rom Drive

Upgrading the CD Rom or optional DVD rom with a CD-RW or DVD/CD-RW drive is easy.  Remove the CD/Floppy module.  Remove the 4 screws that retain the CD drive to the assembly.  Remove the CD Drive and replace with a drive of choice.  Either find a way to obtain a drive with a face plate or you'll have to figure out how to graft the face plate from the old drive to the new.  I opted for the first choice due to the ease of installation.

Upgrading the Memory

Upgrading the memory is a breeze.  There is a memory access cover on the bottom of the laptop.  With the laptop flipped upside down it is the cover on your right side.  The 390E uses PC66 memory and can use a maximum of 2 128mb modules.  The 390X uses PC100 memory and can use a maximum of 2 256mb modules.  A friend of mine recently tossed me 2 256mb PC133 modules.  My 390X did nothing, but complain about them.  Most of the time the laptop would either not post or hang during post.  However the 256mb PC133 modules out of my brothers Sony Viao FX laptop worked flawless. So PC133 memory(not that you gain anything extra from it) is hit and miss.

Upgrading the Processor

Upgrading the processor can be easy or difficult depending on what you are trying to accomplish.  I'm going to break this down by sub-series. 

The 390 series used MMC1 processors.   The fastest MMC1 processors  are only 266mhz.  Honestly I wouldn't spend much time on upgrading the 390.  Gains would more than likely prove to be marginal.  I've never seen the motherboard of a 390 to compare with a 390E motherboard to see if upgrading to the 390E board is an option.  Somthing that needs research is Gateway used MMC1 processors on a couple of Solo models that ran as fast as 400mhz.  I happen to have a 400mhz MMC1 module, but no way to verify if this is a possible upgrade route.  Someone may want to take this info and run with it. 

The 390E series used MMC2 processors which is a bit of a help.  Seeing the 390E only supports a 66mhz bus somewhat limits it's upgradability.  As an example a 390E with a 300mhz processor could easilly be upgraded to a 366mhz.  Anything faster than that can be done, but you'll have to buy an expensive processor to accomplish any gains.  In order to jump to 400mhz would require buying a 750mhz processor.  Any MMC2 processor except celeron which is 600mhz or faster has speedstep technology. A 600mhz processor on a 100mhz non-speedstep capable motherboard will only post at 500mhz.  In the case of the 390E a 600mhz processor would only clock at 333mhz.  No 390 series laptop was ever speedstep capable.  There is a modification that can be done to the speedstep capable processors to lock them in at the higher speed, but I've not had success in making it work so I'm not going to cover it here at this time. 

The 390X is the bad boy of the 390 series.  The 390X supports a 100mhz bus which makes it a worthwhile canidate to consider upgrading,.  Especially if you have one of the PII 400mhz models.  The same issue with using speedstep processors applies to the 390X.  700mhz will be the best you will do unless the processor can be locked to boot at it's faster clock multiplier instead of it's slower multiplier. 

Connecting a TV to the 390E & 390X  using the SVideo out Port

I found connecting a TV to the 390 series a challanging experience.  Since my TV only has RCA inputs made it that much more of a pain.(my next TV will have S-video ports).  I spent good money on several cables that claimed to convert the S-video output to RCA, but none of them proved to work.   After much research I ran across some info about using a ceramic capacitor on one of the outputs on the laptop.  I'll get some pics and instructions done up sometime in the near future on how to build this cable.  It still needs some testing.

Supporting Documentation

IBM Thinkpad 390 Hardware Maintenance Manual (November 1998)
IBM Thinkpad 390X Hardware Maintenance Manual
IBM Thinkpad 390 User's Guide
IBM Thinkpad 390 Setup Guide

Page Created 12/04/2005  Last Updated 04/18/2006