MP975

MP975

Chicony MP975

Resold by ChemBook, AMS Tech, EPS Technology

and many many other companies

Chicony, it seems, sold a great number of these laptops. Other than outer plastic case changes all MP975's are nearly alike under the skin. Chicony called some MP975A and other versions MP975D. However, I've never found out just what was an "A" motherboard and what was a "D" motherboard.

I believe that a few very early MP975's may have had a different floppy disk controller and would be closely related to the MP968 or ARa models than the majority of the MP975's. Early MP975A motherboards were indeed designed to use FAST PAGE memory and had different hard drive controller chips and these early versions are more closely linked to the MP968 design than I first thought. The Cypress Computers web site (see below) is a very good reference page for the MP975 or Cypress 9750 as they called it.

Memory Issues

The Cypress web site (link below) also explains how to identify early MP975's that use Fast Page memory. If you look at the Win 95/98) Device Manager page and open the hard drive controller icon then you can have a very good clue as to the type of memory that you need to install in your MP975. If your hard drive controller is an Opti dual PCI then you should use the EDO modules, else you need Fast Page memory. Almost all MP975's will use EDO memory.

Regardless as to memory type, installing expansion memory requires that both expansion memory must be two identical sized memory modules and installed in pairs. You can not add only one module. You can not mix two different size memory modules. All MP975A machines are limited to a total of 80 MB of RAM which is 2x 32 plus the standard 16 MB installed on the motherboard. Memory modules for these machines are expensive because they are 5 volt 72 pin EDO memory modules or 5 volt 72 PIN Fast Page modules.

Port Replicator Issues

A second major change was that the connector used to interconnect the MP975 to the external port replicator changed at some point and I use this connector to define early (A?) vs. a later (D?) motherboard. If this is correct, I don't know. The two types of port replicator connectors are as follows.

The first type was nearly as tall as all the other connectors on the rear panel and has about 3/4" (19 mm) space between the port replicator port and the PS2 DIN connector end of the port area.

This is the Port Replicator with a Type "A" Male connector - Note how tall and narrow when compared to Type "D"

The other port replicator connector is the one found on most later date MP975's. (and is also found on the MP983) This connector is long and has less height than the Type "A" connector.

This is the Type "D" MP975 connector - Note how long when compared to Type "A"

You can not intermix a Type A or Type D laptop with the opposite type Port Replicator with out damaging the connectors.

Hard Drive Issues

Some early MP975's used a long out of production 3" hard drive that is impossible to purchase today. This 3" hard drive also fits a carrier module that can not be used with a industry standard 2.5" IDE hard drive and is useless today. If you have one of these machines and need (or wish) to replace that hard drive with a new drive you will first need to purchase the later style hard drive module that accepts industry standard 2.5" IDE hard drives. I had a large number of new 2.5" hard drive modules at one time, but I have sold out of them. It is possible to use a Compaq Armada 1500 hard drive caddy kit plus a new outer shell from the newer MP975 to make a make-do module. I do have new outer shells and you can purchase the Compaq caddy on eBay for a few dollars.

General Specifications for all MP975's

All MP975's support Socket 5 Intel CPU's, the MP975 CPU socket lacks the hole that is found in Socket 7's sockets. The Intel 166mmx - 233 mmx CPU's also lack this extra pin and so they drop into the MP975 CPU socket without a problem. Modified MP975's can use the AMD K6-2 CPU's, but the AMD CPU may need to have the addition pin cut off so that it may be inserted into the MP975 CPU socket. In addition, the MP975 Vcc circuit needs to be modified to support the Vcc voltages needed to properly operate the AMD CPU's. With correct modification the MP975 Vcc controller chip circuitry can output the correct 2.0v or 2.2v VCC that these AMD CPU's require.

The BIOS CMOS memory is maintained by a RECHARGEABLE Li battery soldered to the motehrboard. This is not the main laptop battery, but a small battery on the motherboard. If it goes bad for some reason then it must be unsoldered from the motherboard and replaced. However, this battery doesn't go bad all that often. If it left to completely discharge it will give you a CMOS error message the first time that you boot. Just let the AC adaptor recharge the CMOS battery for several hours before you panic. You will need to go into CMOS stup and reset the system defaults plus reset the system clock if this should occur.

So many people have written to me regarding problems with the internal modem that I'm adding this caution:

A phone jack on the side of a MP975 does NOT mean that there is an internal modem installed!

Remove the main battery and look at the top of the battery bay. If there's a 1.5" x 2.5" circuit board and/or gray metal shield up there then you have the modem installed. Else you have a phone jack without internal modem. If you have the modem, then you need to enter BIOS and change the COM2 port setting to modem. When you next boot, windows should find the modem and ask for a driver. I believe that all of these modems are 33.6K and not 56K modems. You can use the Windows 33.6K standard modem driver from my experiences.

Motherboard Revison Details

Revision	BIOS Type	12.1" DS	12." TFT	13.3" TFT	Modem Jack	Video Out
DC31A
DH31	256E0	?	?	?	N	?
LG48A	256??

For additional explanation of the motherboard limits, I've found that the Cypress web site does a good job of explaining the limitations: Cypress Computer's 9750 FAQ

Note: Each Chicony VAR may have their own internal numbering system for BIOS update versions. So be careful when you reflash your BIOS based upon information on other web sites!

A BIOS chip that is incorrectly reflashed may disable your laptop. There is no emergency reflash routine built into these laptops, nor jumpers to allow a "blind" reflash, as found on some desktop motherboards. A bad reflash will require that the BIOS chip be removed and sent to me for reprogramming back to a correct version based upon your motherboard.

PCMCIA

The two PCMCIA Card slots allow two Type II or one III devices. These slots offer both Cardbus (32 bit) and Zoom Video Support. The lower slot is Slot 0 (Slot A) and the upper slot is Slot 1 (Slot B), only Slot 0 can support ZV cards. When a card is inserted into a slot the status LCD will display a "tombstone" with "A" or "B" telling which slot holds a card.

Often dead MP975's will have a PCMCIA "tombstone" that shows up on the status LCD when turned on and these doesn't even require a card in the slot.

CPU's

Does the MP975 support the Intel 233mmx? Answer - Maybe!

A MP975 can support the 233mmx only if the following two conditions are met:

Motherboard version F or later.

BIOS version 1.31 or later.

You can determine the motherboard version from the manufacturer's serial number located near the memory slots and in some cases also on the bottom of the laptop. The third digit in that serial number is the motherboard version number. Do not use AMS Tech S/N - use long bar coded Chicony S/N.

What Type of LCD screen do you have?

With AMS Tech laptops:

AMS Tech machines ending with "CS" have a 12.1" dual matrix LCD's (Example - 101CS)

AMS Tech "CT" models have the 12.1" TFT active matrix display. (Example 105CT)

AMS Tech "CX" models have the 13.3" TFT active matrix display. (Example 105CX)

With other brands, look at the latches for the Lid, if they have curved ends then you have a 13.3" LCD and it is a TFT. If they have sharp (square) corners then it's a 12.1" LCD and may be a TFT or dual scan. A dual scan LCD will use both the contract and brightness adjustment FN keys, the TFT hardly shows any changes when the FN keys are used.

While the 13.3" screen does work on both motherboard types, I've not owned, nor seen, a MP975A that came with one. Other companies may or may not have a code in there model number to tell you which LCD that they installed.

The 12.1" dual scan and 12.1" TFT are exactly the same size and can be told apart by the quality of the video and only with dual scan models does the brightness and contrast work. If you have a dual scan LCD try setting your desktop background color to the darkest blue color on the pallet of colors. The dark background looks better that the lighter blue default color on these LCD's since the ghosting is reduced. Also turn on the mouse tails so that the mouse arrow doesn't disappear when moved.

The TFT machines have limited brightness adjustment only. The TFT is a much nicer looking video, but the most common TFT used on the MP975's was the Lucky Goldstar 12.1" LCD which seems to suffer from a high mechanical failure rate.

Other brands TFT's are sometimes found used with these machines. But the LCD lid is custom made for each brand and so changing to a different brand (or type) of LCD requires a complete lid assembly. Signal cables are also custom.

One of the more common AMS Tech model of there MP975 series was the TravelPro 101CS (MP975A) which came with a 166 mmx CPU chip. The CS meant that it had the 12.1" dual scan LCD. I have successfully over clocked the 166 chip to 200 MHz in few cases. The result is a free CPU speed increase at the expense of early CPU failure. BIOS may not report the faster speed and a test program such as Sandra will be needed to see if you are running at 200 MHz.

However, since an even faster 233 mmx CPU sells for under $50, I feel that over clocking isn't a very good method to boost CPU speed if you are willing to spend some money.

Common Failures with a MP975

1) The CPU socket slides open enough to allow the CPU pins to not make contact. Result is a "dead" laptop. Cure - close the CPU socket.

2) Memory size warning after adding/removing expansion socket memory. Cause BIOS is checking for changes in the system. Fix - enter BIOS with Ctrl - Alt - S and then just exit. This resets the memory size in BIOS.

3) Memory errors after adding memory to the expansion slots. Cause can be bad memory modules or even worse, poorly soldered pins on the expansion memory sockets. If possible test the memory modules in a second machine to see if they are okay. If they you need to use a 10x jewelry's loupe and a tiny screwdriver and prod each pin on the socket connectors where they are soldered to the motherboard. Start with the left socket because this area flexes the most and is were most of the problems have been, in my experience. You are looking for any pin(s) that move sideways when pushed near their solder pad connections.