0175 is a fairly common error on a variety of Thinkpads, both numbered and lettered. You may have tried several methods to clear the error, which does seem fairly catastrophic, however if you can find a way to skip the CRC check and update the BIOS you'll basically be able to reset the CRC and resolve the issue. This can be achieved by doing the following:
Obtain the following items:
- One male DB25 plug for the parallel port.
- Cable
- A switch or jumper.
- A boot disk with the BIOS of the machine (this linked floppy image has had the requirement for a charged battery removed)*
*This boot disk is for the later 755 series but more details on making your own unique BIOS updater without battery can be found here.
The DB25 connector for connecting to the Thinkpad's parallel port needs to be wired as follows (pin to pin)
14 - 11
15 - 9
16 - 12
17 - 13
20 - 25 -> with a switch or jumper inbetween
Once connected to the parallel port, do the following steps:
- Hold the switch or jumper, connecting pins 20/25 whilst powering on the computer - will take about 20 seconds for step 2
- Release the switch once the IBM logo appears
- Restart the machine
- Update the BIOS
Tested on a T20, A21m and 755CE.