TechNotes		July 14, 1995  Vol 1 No 8
Copyright (c) 1995 Dynamic Learning Systems.  All rights reserved worldwide.

Table of Contents
-------------------------
A.	Disclaimer and Cautions
B.	About TechNotes
C.	About Dynamic Learning Systems

1. Communications
		Upgrading a Packard Bell Internal Modem

2. DOS and Windows
		Windows Can't Find the CD-ROM

3. Drives
		Cooling the Hot SCSI Drive
		Finicky Floppy Drives
		Using a CD on an IDE Port

4. Manufacturers and Parts
		Soundscape Drivers
		Getting Creative

5. Memory
		Adding Memory to a 386 Motherboard
		Trouble During a Memory Upgrade
		New Motherboard, Old Memory

6. Motherboards, Ports, and Busses
		Checking for P5 Bugs
		CPU Differences


Disclaimer and Cautions
------------------------------------
	This document is COPYRIGHTED under international law.  This document is provided as an educational service by Dynamic Learning Systems, and is intended to benefit all readers.  Although this document is copyrighted, you may print and re-transmit this document freely, so long as the document is used in its entirety, and credit is given to Dynamic Learning Systems.

	THIS DOCUMENT IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.  The reader assumes the entire risk as to the accuracy and the use of this document.  All PC service and maintenance involves some element of personal risk, as well as risk to the equipment involved.  If you are not comfortable following the information contained herein, refer the work to more qualified personnel.  ALWAYS BACKUP VITAL INFORMATION IF POSSIBLE BEFORE ATTEMPTING ANY TYPE OF SERVICE.


About TechNotes
------------------------
	TechNotes is a compilation of symptoms and solutions for various PC problems.  A new release of TechNotes is released every two weeks.  We welcome your contributions of symptoms, as well as solutions that you have found to your own PC problems.  We also encourage you to contribute enhanced or alternative solutions.  It is our hope to make TechNotes a first-rate tipsheet for PC and peripheral service.  The file name of each TechNote includes its release date.  For example, a file name TN040795 indicates a TechNote (TN) date of April (04) 7th (07), 1995 (95).

About Dynamic Learning Systems
----------------------------------------------
	Dynamic Learning Systems specializes in PC upgrade, maintenance, and troubleshooting topics for electronics/computer enthusiasts and technicians.  We publish The PC Toolbox newsletter.  If you have any questions or contributions for TechNotes, or wish to obtain subscription information for The PC Toolbox, feel free to contact us:

	Dynamic Learning Systems
	P.O. Box 805
	Marlboro, MA  01752  USA
	Fax: 508-898-9995
	CompuServe: 73652,3205
	Internet: sbigelow@cerfnet.com


SECTION 1. Communications
=======================

UPGRADING A PACKARD BELL INTERNAL MODEM

Q. I am working on a Packard Bell i486SX machine with a Phoenix BIOS.  It came with a 2400 baud modem module installed (not installed in a card slot, but has a ribbon cable plugged into the mother board).  When setting the system CMOS configuration, the only options for COM1 are (1) modem, and (2) COM port.  I installed a 28.8KB internal modem on COM1.  It works fine.  However, when booting the system, I get an error message telling me that the system configuration is wrong - regardless of the CMOS setting.

A. It sounds like you have not reviewed all of the available CMOS settings.  On page two of your BIOS you will see a setting for your "internal" (on you motherboard) modem.  Set this to disabled.  This CMOS entry is used only for the modem module installed on your motherboard, and not for your new internal modem.  Once the modem module is disabled, your system should see the 28.8KB internal modem alone, and no longer report an error.


SECTION 2. DOS and Windows
============================

WINDOWS CAN'T FIND THE CD-ROM

Q. I'm trying to install a MediaVision MultiMedia kit CD-ROM on my i486SX2/50 computer.  I've got the software drivers loaded and everything seems fine when it's booting up but the CD-ROM drive does not show up under Windows (i.e. the File Manager).  What's wrong?

A. Since Windows relies on DOS for file access, I suspect that you're having trouble accessing the drive under DOS as well.  Chances are that your low-level device driver has installed properly, but the DOS CD-ROM extension MSCDEX.EXE is either missing from AUTOEXEC.BAT, or is failing to install.  Start a text editor (such as DOS EDIT) and open your AUTOEXEC.BAT file, then look for the MSCDEX entry.  It will appear such as:

C:\SB16\DRV\MSCDEX.EXE /D:MSCD001 /V /M:15

although the path on your system is probably different.  If this command is missing, you sill need to locate MSCDEX on your system, and add an appropriate command line to AUTOEXEC.BAT.  If the command is present, check the command line switches to see that they are all correct, and that they match with the command line switches used in your low-level device driver loaded in CONFIG.SYS.  Also make sure that you are using the very latest version of MSCDEX which is included with MS-DOS 6.22.  You may need to change the path specified in your command line to something like:

c:\dos\mscdex.exe.....

Once the DOS extension is configured and loaded properly, DOS and Windows should be able to locate and use the CD-ROM easily.


SECTION 3. Drives
==================

COOLING THE HOT SCSI DRIVE

Q. I have a SCSI disk drive that is very hot to the touch after it has been running for just a little while.  My last drive was an IDE unit that never got so hot.  The SCSI drive also makes a whine loud enough that it can be heard in another room.  Is this normal?  Is it dangerous?

A. From the physical symptoms you describe, it sounds as if the spindle motor (the motor that spins the platters) is failing.  The whine you hear is probably a high-frequency grinding of the motor bearings - the heat is likely the resulting friction.  It is VERY unusual for a drive to produce a whine that loud, and while it is not a danger to you, your data is at serious risk.  I recommend that you perform an immediate backup of the drive, and replace it as soon as your finances allow.  In the future, a warm drive is not a cause for concern, but then the drive is hot and making loud noise, you need to take immediate action.

FINICKY FLOPPY DRIVES

Q. I just finished building an i486DX2/66 system, and I'm having a problem with both of the floppy drives.  When I try to access drive B: (1.44MB), the system attempts to access both drives, and when I try to access drive A: (1.2MB), I get no response at all.  If I disconnect one of the drives, the other one works fine.  The CMOS is setup correctly and I'm pretty sure all the jumpers are right on the controller card.  Any suggestions?

A. Start by checking any jumpers on the drives themselves - most have a jumper which allows them to be set as A; or B:.  If both are set as B: (and the floppy cable has no 'twist' between drives), you will have a conflict.  Next, check the drive cable and see that each connector is attached securely (and in the proper orientation).  In a normal setup, both drives are jumpered as A:, but a floppy cable with a 'twist' in ribbon wires 10 through 16 flip the signals between the two drives so that even though both drives are jumpered as A:, one will act as B:.  The end-most connector on the floppy cable is for drive A:, while the middle connector is for drive B:.  Check your floppy drive configuration again and see that it follows this approach.

USING A CD ON AN IDE PORT

Q. Can you tell me if I can use a hard disk controller (IDE) to control my IDE CD-ROM drive?  The interface connectors appear similar (they both have the same shape and number of pins).

A. As long as your CD-ROM is an ATAPI-compatible IDE device, you should be able to use it with your IDE controller  Your CD-ROM manual should mention ATAPI (although some don't).  Just plug it in as you would your hard drive.  Remember that you will need an ATAPI driver loaded in CONFIG.SYS (and the DOS CD-ROM extension MSCDEX) before the PC will work with the CD-ROM drive.  Also remember that CD-ROM drives operate much more slowly than hard drives, so don't expect blazing performance.


SECTION 4. Manufacturers & Parts
=============================

SOUNDSCAPE DRIVERS

Q. Does anyone know if Ensoniq has a FTP or WWW site?  I just bought a Soundscape SC2000 sound board and need a driver to run this under OS/2.  Any help would be greatly appreciated.

A. No problem, you can try downloading Ensoniq drivers from http://www.ensoniq.com or download by ftp at ftp.ensoniq.com.  You can also try the web at http://www.engin.umich.edu/~blowery/soundscape.html

GETTING CREATIVE

Q. I need to contact Creative Labs for some new drivers and utilities.  Are there any web or ftp sites on the Internet for Creative Labs?

A. There sure are!  Try contacting Creative Labs on the world-wide web at http://www.creaf.com or try downloading files from their ftp site at ftp.creaf.com.


SECTION 5. Memory
================

ADDING MEMORY TO A 386 MOTHERBOARD

Q. I have been given an old i386 system with a "mini" motherboard.  I want to know if I can upgrade the memory - and what memory configurations are allowable.  The system has an AMI 386 BIOS chip.  Note that there are only four 30-pin SIMM sockets on the motherboard.

A. The answer to your question relies partly on what type of i386 your motherboard is fitted with.  An i386SX uses a 16-bit data bus, so the four SIMM slots are likely two banks (0 and 1).  An i386DX uses a 32-bit data bus, so those four SIMM slots are probably just one bank.  This is important since the number of SIMMs required to fill a bank effect the cost of the upgrade (four SIMMs are more expensive then two SIMMs).  Most i386 systems are upgradeable to 16MB, and you can generally fill banks with 256KB, 1MB, 2MB, or 4MB SIMMs to make 16MB.  For example, suppose you have an i386SX with 2MB on the motherboard (one bank would need two SIMMs).  If you add two 1MB SIMMs, you would have a total of 4MB in the system.  If you add four 1MB SIMMs, you will have a total of 6MB in the system.  It is also possible to mix SIMM sizes between banks (i.e. add 1MB SIMMs in the first bank, while adding 2MB or 4MB SIMMs in the second bank).  If your CPU is an i386DX, you will need to fill all four SIMM slots, so adding four 1MB SIMMs also brings the system memory to 6MB.  When adding memory, remember to update the system CMOS to reflect the correct amount of installed memory.

TROUBLE DURING A MEMORY UPGRADE

Q. I'm in the process of upgrading the memory in my i386SX system.  I'm attempting to upgrade from 1MB to 4MB ram.  My friend purchased four 1MBx9 (70ns) SIMMs.  When I first installed the new memory, I received a message at boot up alerting me to a 'parity error'.  I went into CMOS Setup and exited - hoping for the auto-config feature to make the necessary corrections to installed memory.  During the subsequent bootup, I received a message alerting me to a R/W error and a faulty SIMM in socket #0.  So, did my friend purchase the correct SIMMs?  Could different RAM manufactures be an issue?

A. Before you do anything else, check your user manual and verify that your SIMMs are indeed compatible with the motherboard - most are, but it never hurts to check again.  Also verify that the amount of RAM listed in your CMOS Setup is accurate.  The system will flag an error if the amount of RAM listed does not match the amount of RAM detected.  If the SIMMs turn out to be incorrect, you can usually bring them back and replace them with the correct devices.  If the SIMMs are correct, check for proper installation.  SIMMs are remarkably sensitive to accidental damage from electrostatic discharge.  It is possible that one of the SIMMs was damaged during handling or installation.  Try rotating the SIMMs by one position and see if the problem follows the suspect SIMM (i.e. you then see an error indicating a faulty SIMM in socket #1).  If this is the case, the SIMM is likely defective and should be replaced.

NEW MOTHERBOARD, OLD MEMORY

Q. Several days ago, I upgraded my motherboard from an i386SX/33 to an i486DX2/66.  It is a UM4981 motherboard with 8MB of RAM in two 4MB SIMMs.  I also have a Dynamite ProVideo card (ISA) with 1MB of video RAM.  I'm using DOS 6.22 and WFWG.  My problem is that some (not all) of my DOS programs no longer run - I receive  the following message "Memory allocation problem--system halted".  To correct the problem, I must perform a hard reset.  I am currently using Netroom3 as my memory manager, but have also tried using straight DOS with and without MEMMAKER.  The result is always the same.

A. We must assume that your two 4MB SIMMs are new 72-pin SIMMs designed to accommodate the i486's 32-bit data path.  If this is the case, one of your SIMMs may have an intermittent or marginally defective address - the BIOS memory diagnostic and HIMEM.SYS will often catch catastrophic failures, but they are not renowned for 'stressing' memory to uncover marginal flaws.  I suggest that you try running a more demanding memory diagnostic and allow it to run in 'burn-in' mode to stress the RAM for a prolonged period.  This should uncover marginal problems in your SIMMs.  If a SIMM should be reported bad, replace it.  If a diagnostic does not uncover a problem, check your CMOS configuration and see that any values specifying memory are set properly - including wait states.


SECTION 6. Motherboards and Busses
===================================

CHECKING FOR P5 BUGS

Q. I am trying to learn more about the floating-point bug in the Intel Pentium microprocessor.  Are there any shareware or freeware utilities that I can get from the Internet to check my systems for the existence of these bugs?

A. Help is readily available.  You can get a Windows utility called PENTST.ZIP to check for the Pentium bug at ftp.oak.oakland.edu.  You can also try the PC Magazine Pentium Test utility from http://www.ziff.com:8001/~pcmag

CPU DIFFERENCES

Q. I have been hearing the terms P24D, P24T, and P5 used regularly in 'techie talk', but could you explain simply what these things are?

A. These are three DIFFERENT classes of microprocessor.  The P24D is basically an Intel i486DX2/66 which includes a write-back cache.  The availability of this internal cache would improve the CPU's performance in systems WITHOUT an external (L2) cache.  The P24T is the long-awaited Pentium Overdrive - a scaled back version of the Pentium packaged to fit in an i486 CPU socket.  The P5 is the 'shorthand notation' for the full-fledged Intel Pentium microprocessor (which is incompatible with i486 motherboards).

