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T3100 - what to look at first

alank2

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I picked it up fro $30 in a garage sale this morning with a nice zipper case. It powers on and the display looks great, but it griped about the hard disk and I don't ever see it trying to access the floppy drive. Should I open it up and check the power supply voltage outputs first?

Is there a service manual for it?
 
Getting somewhere now!

Got it booting - I thought it was only a 720K drive, but it is 1.44M!

It is a 3100e - setup gives the option of 20M or 40M hard drive, but it will not boot saying there is a problem with the hdd controller. I think I can hear the HDD spin up at power on.

The keyboard is a bit flaky often typing an extra character or two - not sure what to look at on that.

Any tips on the HDD for what to look at? I ran the test3 and when it tests the HDD it says ABORTED 805101
 
It looks like you have to disassemble/remove the display to get at the hard drive. Does anyone know if the T3100e can run with an external monitor without the internal display connected safely? That would be useful for testing/trying to find a drive without reassembling it.
 
It has really been disassembled. I'm using some JB weld on the hinge parts where the threaded inserts broke away from the plastic mounts.

I found a 1.6G drive that seems to work in it. The BIOS only has two options though, 20M or 40M.

I think I found in the BIOS where the table is though and I might have some OTP EEPROM's I could burn (which doesn't give a lot of option for retrying).

bios.png

I found a page which shows:

Model BIOS type selection Cylinders Heads Sectors per track Capacity Seek time
Conner CP-3022 Type 11 615 4 17 20 MB (Formatted 21.4 MB) 27 ms
Conner CP-3024 Type 11 615 4 17 20 MB (Formatted 21.4 MB) 27 ms
: ? : Type 12 980 5 17 40 MB (Formatted 42.8 MB) 25 ms

615 cylinders -> 0x67 0x02, 4 heads 0x04, 17 spt = 0x11
980 cylinders -> 0xd4 0x03, 5 heads 0x05, 17 spt = 0x11

Does the 0xE4A0 make any sense? I see the first drive in it, but it lists the cylinders twice (0xE4A1 and 0xE4AD), then the heads at 0xE4A3 and the spt at 0xE4AF.
Then the second drive appears at 0xE4B0.

Any thoughts on why they would list the cylinder twice?

The drive I installed has 3148 cyl, 16 hd, 63 spt.
 
I modified the BIOS, but ran into a checksum error. Does anyone know how Toshiba does their BIOS checksums?
 
The extra parameter that looks like a dupe of the cylinder count could be 'landing zone'

As for the checksum, could it be the same as for option ROMs? The last byte would hold a sum of all previous bytes, negated.
 
Thank you for the checksum tip!!! That was it. As it turns out, the checksum being a single byte was only in the odd EEPROM. Using one time programmable EEPROM I can lower bits, but I can't raise them, so I found some unimportant bits to lower that made a checksum I could also lower bits to get to, and ... no more checksum error! I didn't even have to flash another OTP EEPROM IC and could use the two I started with this morning!

So, interestingly, my drive which is 3148 cyl, 16 heads, 63 spt ends up being reported to DOS/int13 as having 1023 cylinders. MS-DOS 6.22 fdisk/format got me a workable 500M partition which is certainly much better than 40M.

The BIOS does show the correct 3148 number in setup when I look at it, so its int13 function must compare that number and if larger than 1023, it sets it to 1023. Had it just kept the lowest 10 bits I would have had (3148 & 1023) been 76 cylinders.
 
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