• Please review our updated Terms and Rules here

compaq portable/luggable docs, tech ref?

M

mosfeat

New Member
Joined
Oct 13, 2008
Messages
9
Location
In flight
I have acquired an ailing compaq portable (original silver label, single floppy, but HH centered). I am looking for a pointer to a tech ref (and/or schematics to save time). At least, the settings for the DIP switches would be useful.

The floppy spins on boot but won't read and the keyboard is non-responsive for starters. There is no BIOS info until I get the can't read diskette, hit any key.. message, which I assume is normal for this version.

All the connections have been cleaned and reseated, and I am about to swap the drive and start scoping signals.
 
Patscc: Correct, the first luggable, silver label, 8088 4.77. Has FDC/Printer card and video card.

BIOS is marked as: 10666-001 Rec C
System board is: 000004-001 Rev N

There are no BIOS POST message (identifier, mem, etc) until the ~ can't read the diskette, hit any key to continue message, after the drive spins up. I know the later model (horizontal drives) I had at one time did have POST messages, but have no idea if there were present on this model.

Fallo: thanks for the link.
 
message

message

I'm just dense today.
So on the screen you actually see:

hit any key to continue message

If I got it right, I think you're floppy (you're using a 360k boot disk,right) just needs a bit of cleaning/lubing.
If gets to the trying to boot stage, then it's passed POST.
patscc
 
mosfeat said:
Patscc: Correct, the first luggable, silver label, 8088 4.77. Has FDC/Printer card and video card.

BIOS is marked as: 10666-001 Rec C
System board is: 000004-001 Rev N

There are no BIOS POST message (identifier, mem, etc) until the ~ can't read the diskette, hit any key to continue message, after the drive spins up. I know the later model (horizontal drives) I had at one time did have POST messages, but have no idea if there were present on this model.
Click to expand...

Apparently not, since the original Portable was modeled after the IBM 5150, which did not display a memory count or any kind of startup message.

The Revision C Compaq BIOS is functionally equivalent to IBM's 10/27/82 BIOS, meaning that it can use the full 640k of memory, hard disks, and EGA/VGA.
 
Got a few minutes with the luggable today.

Both the drive and the controller have some problems. I dug up another 360k floppy to test with and found the controller has signal dropouts so I'll check caps and the drivers. Using a different machine, I also found that the compaq floppy starts on read req (boot) and then stops after a few seconds--starts a read operation (spin-up, head studders and then just sits spinning). Heads have been cleaned by hand with clean room cloth and pure alcohol, lubed and term is good.

The drive is a Mitsubishi M4851-352U HH with a FH bezel. There are four goups of three test points on the logic board. Anyone have a list of the test points or a service sheet? I am going to poke around for the signal level TPs and see if they are good and the alignment is adequate (strongest signal as I have no alignment disk).

3254039909
 
Last edited:
i have a portable plus that some times does this (as well as sometimes not turn on). the way i fix it is to pick it up and shake it. lol
 
You must log in or register to reply here.
Back
Top