Comments- There are at least five Linear Tech chips concentrated in the upper right that I didn't show. There are solder spots for a 60 pin header under the right side of the heatsink. The double box around the 386SX-20 is where there is a double row of solder pads that are all connected to the SMD leads of the 386SX. Possible upgrade that never showed up?
   The speaker wires aren't very sturdy. You can rip the wire pad right off the speaker if you aren't careful. I wasn't...

David Beem pipes up 
My L40SX planar (FRU 95F4879) has chip components numbered differently, all other components are identified the same - Datecodes are from the 14th through 27th week 1991, BIOS date 1991:

External keyboards are not supported. 80387SX Math Coprocessor PLCC

When two 8MB memory modules are installed in the system unit, the planar's onboard 2MB of memory is allocated by automatic configuration as 2MB of EMS memory since the 386SX CPU can only address a maximum of 16MB extended RAM. This memory can then be used with a special driver IBM provides on the L40SX starter diskette. This driver is installable by means of the UINSTALL utility provided on the starter disk.

The driver is easily installed by UINSTALL but IBM warns you not to install the driver if you are a Windows 3.0 user. I decided to install the driver on my maxed-out L40 anyway since it didn't cause trouble with Windows 3.10. However, after transferring the 8MB part from one L40 to my other one, Windows for Workgroups 3.11 refused to start, complaining that an incompatible EMS driver was being loaded.

David L. Beem looked in his Windows 3.1 resource kit and found the answer to my problem. A simple addition of

IgnoreInstalledEMM=On

to the Windows SYSTEM.INI file under the [386Enh] section solved the problem and made the system work great with IBM's EMS driver.

Update: An attempt to create a RAM disk using the EMS RAM and booting Windows 3.11 resulted in total loss of the data on the RAM disk even though Windows did see it.

Modifying standard SIMMs to L40 is HERE
2,4, or 8MB 80ns (expandable to 18MB)
Supposedly, using two 4MB SIMMs is NOT supported.

 (by William Walsh)
The L40SX has 2MB of planar memory. Some units may have at least one 4MB module installed. In either case, more memory than 2 or 6MB total may be desired. This is where things get a little bit interesting, as the L40 uses lower power SIMMs and standard SIMMs might not work.

4MB SIMMs have been successfully converted for use in the L40SX by more than one person. However, it is supposed that you can only use one 4MB SIMM in the system--two are simply not allowed. (Anyone want to prove or disprove this?) 

No modifications to 8MB modules have worked as of this writing (04/2002). However, a somewhat satisfactory solution using modified 16MB modules at half capacity has been found. I have been lucky enough to find two L40 with genuine 8MB modules in them, so I have not attempted any modifications.

The one module I had modified for me (a 4MB module) by David Beem was rejected by both my L40SX. It was usable and passed diagnostics, but gave a constant "164" from the system at POST.

FRU 79F0983 PN 72X6074 Panasonic JU-237AO3W
Cable FRU 79F0987 PN 65F0223 by Rogers

   Floppy is in a carrier and it has a metalized plastic shield around all sides but the front. Small cutout for the drive connectors in the back. The cable is the much beloved tape style. 17mm high "super slim" 3.5-inch floppy disk drive

60MB HD 79F1009 Connor CP2067 5v 640 mA
80MB HD 95F4714
Cable, HD FRU 79F0988 PN 65F0224
MFR ID 31745, same print style as the floppy cable, marked as being made by Rogers.

Due to its vintage, the L40 undoubtedly has the 504M limit disease on native BIOS support. You can use a Disk Manager software package to overcome this limit.

Unless you buy a standalone disk manager program, free ones provided by drive makers will generally only work with that manufacturer's drives...

Peter Wendt sez:
Not long ago I installed an 850MB drive on Martins L40SX with Microhouse EZDrive - must have been an older version. Worked like a charm with no problems after setting the IDE Master jumper right.

If you want an alternative product: Look in the "support / download" pages at www.maxtor.com and download the stand-alone (bootable) version of MaxBlast ...

Switching from Trackball to Mouse operation (or the other way around)

1. Hold pointing device by sides with track ball facing up.
2. Press latch cover buttons and pull top cover toward you. The top cover will release.
3. Pull top cover until top is in locked position.
4. Turn pointing device over so trackball is now facing down.
 
 

Function Of Trackball Mode Buttons

The two small buttons facing the front of the Trackpoint enable drag lock for either the left or right buttons. The two large buttons function as normal "click buttons".

Installation

Turn off the computer and all attached options. Connect the pointing device directly to the pointing device connector on the computer or on the pointing device passthrough located on the numeric keypad.

Note: When using any of these commands, type only highlit letters in the above tables.

[SET], SET, and — in the left column of this table.

[SET] Indicates that you can omit the value, SET, for option1, If you specify SET, the command you enter is stored and remains in the computer memory even though the power, switch is turned off. If you do not specify SET, the command is no longer in effect when the power switch is turned off.

SET Indicates that you cannot omit the value, SET, for option1.

— Indicates that you cannot specify the value, SET, for option 1.

* Indicates that this command is not supported in the OS/2 environment.

PS2 Command Examples 

IBM PS/2 Communication Cartridge I (3541-001) P/N 06G8051 / FRU 06G8066

3541-001 Communications Cartridge PCB (Bottom)

Q.. Is there any way to attach a LAN or terminal emulation adapter to the L40SX?
A. The PS/2 Communication Cartridge I (Type 3541) is an A/C-powered external expansion cabinet that can take one half-length adapter. It is intended for use with network or terminal emulation adapters (such as 3270 and 5250). At 7.1 x 3.4 x 5.7 inches, and 2.6 lbs., it is small and light enough to be taken on the road with the laptop.

Q. The announcement letter says that only LAN adapters, 3270 and 5250 emulation adapters are supported in the Communications Cartridge I. Can other adapters be used as well?
A. Generally speaking, yes, if the adapter is 8" long or less. There will be some adapters that won't work, however; memory and video adapters, for example. Also, the IBM SDLC adapter is known not to work. (It can only be configured as COM1 or COM2, which are reserved by the L40 for the built-in serial port and the optional serial port or fax/modem.)

Troubleshooting

Q. I can't seem to print anything.
A. Make sure your parallel port is turned on. Use PS2.EXE to check the status of your ports.

Q. My communication software to recognize my serial port (or internal fax/modem).
A. Make sure your serial port is turned on. Use PS2.EXE to check the status of your ports.

Q. I can't get my serial mouse to work.
A. Make sure your serial port is turned on. Use PS2.EXE to check the status of your ports.

U10 Unk
U11 Yamaha YM7109C-J
U13 KM62256ALG-10
 
 
 
 
 
 
 

J1 50 pin header
U3 Firmware FR 101
U4 80C32-1
U5 SSI 73D215A-CH
U6 SSI 73M214A-IH
Y1 14.745 M osc
Y2 9.830 M osc
 
SSI 73D214A-IH Modem Analog Front End Datasheet
SSI 73D215A-CH Receiver Digital Processor
Yamaha YM7109C-J MD96FX 9600bps FAX MODEM LSI  Datasheet

Interesting, uses the 80C32-1 CPU... It supports data (up to 2400bps) and fax (9600bps) communications, and standard Hayes AT commands.

Updated Fax/Modem Fixes Fax Issues

FRU P/N79F0996 is the updated Data/Fax modem. FCCID ANO85431198A

Older Internal Data Fax Modems may fail when using a FAX program, but they pass diagnostics.

      Some down level Data Fax Modems may not operate with class one FAX programs.  If the system is experiencing FAX program hangs when trying to transmit or receive data, run the advanced FAX diagnostic from the reference diskette. If this operates correctly check the modem for the part number in the physical check section. If part number 06G9210 is NOT on the fax modem,  the modem may be affected.

Directly supported printers
DICONIX raphics Printer
HP LaserJet Series II
IBM PC Graphics Printer
IBM Proprinter  I/XL
Okidata ML192/193        Native mode 
Diconix 150              DOES NOT WORK!!!

Q. What is the syntax of the FAX command to use with the L40 Fax/Modem?
A. The FAX command must be followed by a file name and phone number to dial. There is no "front end" to the program; it is strictly command line driven. The file transmitted must be straight ASCII or a PCX graphics file. You may use a plus (+) sign between files to send them contiguously, without page breaks between (for example, a business letterhead followed by the letter) or just one name after another to send them as separate pages. The phone number uses the standard Hayes (AT) modem command set.

Q.. What fax software can I use with the L40 Fax/Modem option?
A. No special software is needed. The Fax/Modem option includes a program that provides basic Send/Receive, View, Print, and Set Options features. The software will accept ASCII, PCX, TIFF, or fax file formats for transmission.

Q. If the Fax/Modem is in an L40 with the speed turned down to 5 or 10MHz, will this affect the performance or accuracy of the Fax input/output?
A. The Fax/Modem is not supported at 5MHz; for best results in a multitasking environment, such as in the OS/2 DOS box, or under Windows, the 20MHz speed should be used.

Q. External monitor will not work off PS/2 Model L40 VGA port; the monitor is blank.
A. To use the external VGA port, you must first use setup program to change display type from LCD to CRT. Once this is done, the video signal will be rerouted to external monitor.

Q. When I attach an external monitor or projection device to the PS/2 Model L40 VGA port, the LCD goes blank. Is there any way to have both displays working simultaneously (for doing demonstrations to large audiences)?

A. Only one display can be used at a time; either the built-in LCD, or an external monitor or projection device. However, some devices that convert VGA output to "standard" analog RGB output for video projectors have video cables with "piggyback" VGA connectors, so that a monitor can connect to the back of the plug that goes into the VGA port. In this manner, the demonstrator has an external monitor to look at, while the audience sees the projection screen. (One such conversion box is called the Extron 109, manufactured by Covid Electronics. Other such products may also exist; this is not meant as an endorsement of this particular vendor or product; merely an example.)

OS/2

Q. What's the minimum OS/2 version required for the L40?
A. OS/2 V1.30.1 is the minimum requirement.

BSD / Linux on 8543

Alfred Arnold takes a guess with:
   I don't think it's impossible.  My L40SX has 8MB, hard drives up to the 500MB limit shouldn't be a problem and from the software's point of view, it's a 32-bit system.  That's quite enough for an older Linux or BSD installation, though it might not be much fun to work with it ;-)

W95

William Walsh went for it:

A while back I installed Win95 on my L40SX. The experience went pretty well and speed wasn't all that bad...maybe not on the order of using it this way for serious work, but fast enough for tinkering.

Anyway...Windows 95 didn't detect the onboard VGA as plain VGA. The chipset used is a Western Digital something and that's what Win95 found. I have not been able to locate a data sheet for the IC used, but I wonder if it is capable of more than plain VGA with a memory upgrade/hack?

I suppose the likelihood of the internal panel supporting more than 16 grays is not good, but an external CRT could always be used for the higher up modes.