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5150 Post Code 601

L

lyonadmiral

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Interesting issue regarding this POST code. 601 is "disk power on diagnostics test failed" however, the DIP switches are set to ZERO drives installed, the only card installed in the system is the Mono/Printer card. What could be causing the issue?

Thanks,
Daniel
 
Then how did you configure a 5150 that had no drives and used cassette only? Because even the Guide to Operations, offers the option of setting the DIP switches for zero drives.
 
According to the Guide to Operations; Bank 1, Switches 1, 7, 8 are to be set on for 0 drive operation. I just went to my workbench to doublecheck that configuration and it is set as such, however upon cold or warm boot, I still get a 601 error.
 
lyonadmiral said:
According to the Guide to Operations; Bank 1, Switches 1, 7, 8 are to be set on for 0 drive operation. I just went to my workbench to doublecheck that configuration and it is set as such, however upon cold or warm boot, I still get a 601 error.
Click to expand...
Maybe those switch settings applied to the first and second 5150 BIOS revisions, and in the move to the third BIOS, IBM changed the switch 1 purpose (to 'boot from floppy drives') but did not reflect that in the later manuals. I'll investigate (when I'm finished my present activity).
 
My 'change of behaviour' hypothesis was incorrect.
For the first, second and third revisions of 5150 BIOS, switch 1 on switch block SW1 does:

ON = No floppy controller present (if present, ignore it)
OFF = Floppy controller is present - drive count in switches 7 and 8 - give '601' error during POST if a problem found with controller or first floppy drive

Alternatively,

ON = No floppy drives
OFF = One or more floppy drives - drive count in switches 7 and 8 - give '601' error during POST if a problem found with controller or first floppy drive

So it sounds like your switch 1 on switch block SW1 is still off.
 
lyonadmiral said:
According to the Guide to Operations; Bank 1, Switches 1, 7, 8 are to be set on for 0 drive operation. I just went to my workbench to doublecheck that configuration and it is set as such, however upon cold or warm boot, I still get a 601 error.
Click to expand...

That's also what the V2.02 Techref says (Page G-6). What BIOS revision are you using?
 
We're trying to get the full list of what the switches are set to, which is more polite than asking "are you sure you flipped them the right way" :)
patscc
 
patscc said:
I don't have a 5150 handy to try this out.
The 5150 doesn't care what 7&8 are set to when it's set to boot to BASIC, right ?
Click to expand...
Looking at the 5150 POST code, if switch 1 on SW1 is on, the POST skips the 601 test (floppy controller and first floppy drive), and at bootstrap time, jumps to BASIC.

Even if switch 1 on SW1 is off (i.e. at least one floppy drive present), the 601 test in the POST doesn't read switches 7 and 8. It doesn't need to. Of the floppy drives, the 601 test tests only the first one.

Switches 7 and 8, the settings of which the POST stores in the BIOS Data Area, will be looked at by the OS.

I do not think that switch 1 should be referred to a 'boot to BASIC' switch, because I'm sure that if I added a hard drive and controller, the 5150 (third BIOS) will boot to hard drive if switch 1 is ON.
 
You've got 256k in there, correct ? And the 8087 is physically present ?
Do you have a VGA you can slap in there instead of the mono card ?
patscc
 
The reason I ask about the BIOS is that the 5160 calls SW1 "unused" and the XT documentation seems to imply that you must have a floppy controller installed.
 
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