Two T21s, two different motherboard problems

[astral]

First time poster here. I've got plenty of electronics experience but I need ThinkPad help and this seemed like the place to go.

I recently picked up two T21s, and neither of them work properly.

T21 #1
Shows the CRC1 checksum error. I looked it up and it seems to be a common issue on these. I saw plenty of solutions, from replacing the chip causing the error to rigging a parallel port contraption to bypass it and reflash the BIOS, but I'm not sure what the most up to date fix is.

T21 #2
This one rarely posts successfully. When I could get it to work it worked just fine, and I found out that my battery worked, but most of the time I just get 2 of the LED lights to flash for a second and it doesn't do anything else. I found some old threads from the 2000s, but being during the machine's usable life the replies suggested replacing the main board, which isn't a great option now. I heard one or two sources claiming the issue was a capacitor in the battery circuit. In that case I do have the skills to replace it, just not sure which it is, and I'd rather not order caps if I don't have confirmation it could actually fix the issue.

I really don't want to junk these guys, they're really neat laptops and I'd love to use one of them as an old Windows laptop to add to my collection.

Edit: Just got out T21 #2 and it started! But I had no RAM installed so it just beeped. Installed RAM, and back to the same old issue. It did this before though, I'll bet if I leave it for several hours I'll get it to start again.
Edit #2: Looks like it could be the Atmel ADP3421 chip? If so then crap, I don't have the right tools to replace an SMD chip like this. Could it possibly be something else?

Thanks for the help,
astral

[SMA]

T21 #1
There are at least two possible CRC errors.
For me, the parallel port dongle worked with a CRC1 0175 error, but not with a CRC1 0188 error.
If you have the CRC1 0175 error, then I will say you should go for the dongle solution.
To perform a regular BIOS update, you will need a working battery and possibly a floppy drive.

T21 #2
Sound like the Blink of Death error (BoD).
The are pleanty of information on this on the forum, but there is no single solution that will work every time.

[astral]

Thank you for the reply! I’m currently tinkering with the first T21, it still posts but with the CRC error. (0175 luckily). I’ve got wires but no dongle, is it possible to just stick the wire directly into the port with no external dongle? I do have a male-male DB25 cable that I use for SCSI but that’s it unfortunately. I don’t have an ultrabay floppy drive but the battery works, and I have a hard drive with an already configured Win2k install for a T21. Hopefully I can get the error bypassed and reflash the BIOS from Windows.

[SMA]

It is just a DB25 male connector to which you will solder some wires. Shouldn't be that difficult to obtain.
I cannot say if it will work with wires directly into the port - may depend on the thickness of the wires used.

You can leave pin 20 and 25 unconnected (that is - forget about the switch mentioned) - it is not needed.

[astral]

Just plugged wires directly into the port and saw this thing boot to Windows for the first time since I got it. Thank you! Now I’ve gotta get this thing to do a BIOS update, and I should be good. Thank god my battery works!

Edit: BIOS updated successfully. I'll have to do more testing, but it's booted successfully without the parallel port wires installed! Thank you very much for the help.

astral

[solidpro]

>>For me, the parallel port dongle worked with a CRC1 0175 error, but not with a CRC1 0188 error.

Astral - we seem to be working on the same kinds of machines at the same time.
I concur with this. I had two T20s, one with 0175 and another with 0188. Yesterday, the 0175 was cured by building the 'parallel port dongle' and shorting pins 20/25 during power up (allowed me to bypass CRC check and relfash the BIOS using floppy).

0188 is still unsolved... Which is a real shame because it's a near complete, decent condition machine. However I can't get past 0188 and most people seem to say 'junk' on google searches...

[astral]

I haven't heard that one before. I hope you can find a fix, maybe there's another unknown parallel port wire solution that we just don't know about. T21 has been more or less stable, it's shut off a few times but I think that may be an overheating issue. I replaced the thermal paste which should help I'd hope. It's a fine machine, great for Win2k.

[SMA]

I am convinced that a crc1 0188 error can be fixed by either
replacing the content of the rf08 eeprom chip - load with the content of another rf08 chip from a Thinkpad of the the same type or
replace the rf08 chip with one from a similar Thinkpad type

[solidpro]

SMA...

1) have you tried?

2) I would if I had any other similar-era broken machines laying around, but unfortunately do not...... Was the rf08 in the 600?

Thanks

[SMA]

1)
Many years ago I have have fixed a couple of CRC1 0175 errors by replacing the contence of the rf08 chip.
(That was long before we knew about the dongle option)
I have never come around to trying it with a CRC1 0188 error, but both errors are caused by bad checksum
errors in the rf08 data - the error code coming depends on what block within that eeprom is bad.

2)
Thinkpad 600 uses AT24C01A eeprom.
Thinkpad 600X and T20 uses AT24RF08CT - but it is very unlikely that their data will be compatible


EDIT: on T20 you can see the RF08 chip below the front memory module

[solidpro]

Hi

Does the T20 have the same eeprom? I actually have the issue on a T20

cheers

[mikemex]

EEPROM doesn't store information indefinitely. Makes you to think what will happen in the long term to the information stored in SSDs...

[RealBlackStuff]

T20/T21/T22/T23 all use the same 14-pin Atmel 24RF08C EEPROM.