Wednesday, May 4, 2016

The Compaq Portable III

Post dedicated to my friend Thomas H.

  The Compaq Portable III is a computer released by Compaq Computer Corporation in 1987. It was advertised as being much smaller and lighter than the previous portable x86-PCs, however it was still quite large by today's standards.

  Its street price upon its release was 4999 USD for a model equipped initially with an 12 MHz Intel 80286 and later 20 MHz Intel 80386 CPU, 640 KB RAM,1.2 MB 5.25" floppy, 20 /40 /60 MB hard disk, and a 10" amber colored gas-plasma display or 5799 USD with the upgraded 40 MB hard disk. There was also an optional ISA Expansion chassis allowed for 2 full length 16-bit ISA add-in cards for 199 USD. Power is supplied using a mains electricity outlet, no battery exists.


     Compaq actually released a 286 version to restore its Number One spot in the portable market, under the pressure from Toshiba with its T-1100 and T-3100 (which happens to be in my collection) and Zenith with its Z-181. The specs are very similar to the Toshiba T3100 but it has been reported to be more faster than the Toshiba.

     I decided to write about this awesome PC as a friend of mine will get his hands on this machine really soon, so I decided to spear his time with the searches.
So I started to google about it so we can start the machine together as the technical condition of the purchase is unknown.

Unlike modern computers, there is no BIOS or set-up screen in the Compaq Portable III, same as the IBM P70 System which I will write soon. To start up the machine you will definitely need a COMPAQ DIAGNOSTIC DISK.

You can download and create a "Compaq Diagnostic" disk _ here_.

Download this PDF file for system jumpers, switches, part numbers and upgrade options.

The biggest issue is that most machines come with a 5.25 FDD unit, that makes it very hard for the user to create the Diagnostic Disk. However I do have 5.25 diskettes and also a computer that has both 5.25 FDD and a standard 3.5 FDD.

If you require this COMPAQ DIAGNOSTIC disk please email me and I will ship the 5.25 disk worldwide.


COMPAQ PORTABLE III general issues (some issues are caused by the aging of the machines components)

1) Replacing the 5.25 FDD unit with a 3.5 unit. 

-this is almost impossible as COMPAQ was selling this upgrade mounting kit w\bezel 30 years ago... I couldn`t find any on e-bay or other similar sites.

2) Power supply failures, usually there are 2 types of failures. 

-one is caused by bad CAPS, see picture "Pic_1".

When you have bad CAPS in most of the cases you will try to power on your machine and a RED light will blink several times. That is the Power Supply in fault mode. (Stipulated in the User Manual)

-the other cause when your machine won`t power up is the socket between the motherboard and the power supply, but then you don`t have the blinking RED light... or the Power supply is busted but that happens rarely.

Note: The CAPS don`t have to look bulky like the ones in Pic_1, they can look great but still they are not working as the acid from the CAPS leak and short circuit the CAPS.

From my experience I saved 99% of the power supplies just by exchanging the CAPS.

3) Sticky rubber handle. 

-if your machine has a sticky rubber handle is because of the chemical agents in the rubber that wipe away in time and the quality of the rubber will fade as a sticky TAR. You can`t do much about it but you can use some wide scotch transparent tape. That will protect the original rubber coating and your hands won`t get sticky :)

4) The keyboard cable rubber is falling off. 

I had this problem with my Compaq Portable 486C as well and it looks like you have to exchange the cable. As it is IBM COMPATIBLE PC you may use a nice curly cable from an IBM model M keyboard or any other curly cable keyboards from 1987 to 1993. 

Disassembling the unit

What you need:

 1 x Phillips screwdriver   +
 1 x Phillips scredriver      -
 1 x TORX T15
 Infinite Patience :)

Usually it is good to think as a long term project, if you try to solve everything in 1 day like most of us... you will get frustrated and never solve the problem...

I got the User manual that containse the service one as well from my archive as I used to own one.

1. DOWNLOAD the USER\SERVICE MANUAL (if download dosnt start please contact me over email)

-don`t print it unless you want to kill a forest :) !!!!!!!!!!!

The disassemble procedure is stated starting page 69.

Note that for you to disassemble it... you don`t have to take off the chips on the motherboard or fully disassemble everything. Try only to disassemble it modular... big chunks. 

The manual is very detailed so with minimum skills and patience, you can do this!

I hope you enjoyed the post!

Bogdan Tirziu

No comments:

Post a Comment