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IBM 5155 floppy drives unable to boot computer

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bettablue

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As most you all know, I just recieveD a very nice example of an IBM 5155 luggable computer. However there is one drawback. Neither of the 5.25" half height floppy drives will read any of my DOS 3.3 boot discs. The floppies work just fine in my IBM 5150 and 5160 computers, so I know the problem is in the 5155 poor tabes.

So my question is this. How does the cover come off too open and remove the computers case, and then, how difficult it is to properly clean and check the drives once they're removed?

I know I have another floppy drive in one of the boxes in my garage since we moved into my new home, so in theory, I "could" install it in place of one of the two floppy discs in the 5155. However the drive is tan in color, and the original 5155 have a black face plate.

So, does anyone have any info I can use to get my PC working, besides getting one of The more modern USB, or thumb drives?

As always... Many thanks in advance.

Thomas
 
You might not need to remove them. Check the cables first for correct insertion, especially at the controller end.

Also, clean the heads on the drives.

Then check the floppy controller.

Now you've piqued my interest:
bettablue said:
So, does anyone have any info I can use to get my PC working, besides getting one of The more modern USB, or thumb drives?
Click to expand...
How do you propose to get this 'USB or thumb drive' working with an 8088? AFAIK, this technology does not work with ISA-only boards. Do you know something we all should be made aware of?
 
Thomas are you referring to one of those floppy drive emulators that use an USB drive?

Will they work with an 8088?
 
Last edited:
Stone said:
Now you've piqued my interest:
How do you propose to get this 'USB or thumb drive' working with an 8088? AFAIK, this technology does not work with ISA-only boards. Do you know something we all should be made aware of?
Click to expand...
Some of the cheaper floppy emulators use USB flash storage. Like this one, for example: http://www.ebay.com/itm/like/131818390146?lpid=82&chn=ps&ul_noapp=true
The USB only has to interface with whatever microcontroller they are using. The microcontroller itself connects to the PC via the floppy connector.
 
For an XT you'd probably want a DD (720 or 360) variant and a new floppy cable (or adapter), but they do work.
There is also the USB ISA card that people are playing with at the moment.

But anywho, I agree with "clean the heads". I would use a cleaning disk, some cleaning fluid / isoproply, and leave the case on.
 
Thomas, I'll add my vote for cleaning the drive heads first. If you have a head-cleaning diskette (use ONLY the wet ones), just stick it into the drive before the system boots. Since the drive can't read any data on the cleaning diskette, it should boot to Cassette BASIC. Eject the diskette, let the cleaning solution evaporate for a few minutes, then restart the computer with your DOS diskette. I've done this with my 360KB and 1.2MB drives over the years with much success.

As for taking the 5155 apart, it's not as simple as the 5150/5160/5161. I know; in fact, I have to take my 5155 apart soon to do some testing. But if you want the details, have a look at modem7's site:

http://minuszerodegrees.net/manuals/IBM_5155_Guide_to_Operations_6936571_JAN84.pdf

The section you'll be looking for is Chapter 4 (page 229 in the PDF). Since this is the first time you're taking apart a Portable PC, be sure to follow the directions to the letter! This will help prevent damage to the case/monitor, as well as prevent small screws from falling into the motherboard (or worse, under the motherboard/monitor). If my memory serves, aside from the standard screwdrivers, you'll also need an Allen wrench to remove the diskette drives (can't remember the size at the moment).

Once you get the covers off, I'd try just swapping the disk drive data cable connectors for drives A and B. Then, power on your Portable, and try to boot from the secondary drive. If that works, then you know the primary drive is faulty.

Hope that helps!

Jon
 
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