Service Forum

[rkawakami]

In response to a couple of questions posed by "noyp", I have put up another web site describing in detail how I laid out my driven interface breadboard. Hopefully it contains enough information on the "whys" and "hows" that one would encounter when trying to duplicate what I did.

http://www.rkawakami.net/ibm_600x/max232_if/

Ray

[victor]

For Thinkpad R40 users here is a nice pictured tutorial received from one of our members who is a photographer. The pictures resolution was very high so I had to reduce them to a more downloadable format.
Winrar is needed to unrar the pictures.

http://www.allservice.ro/forum/dl/r40-tutorial.rar

Enjoy!

[basscleff]

Great information here, once again!
I wonder if anyone can confirm alternate solder locations for a Thinkpad A21m motherboard? Might they be similar to the other ilustrations posted for alternate solder points, that are not on the eeprom itself? (alternate Gnd, SCA and SCL solder points or pads)
thank you!

[rkawakami]

Just wanted to update this thread with an unlock procedure I've performed on a T21 and T23. Both of these laptops have the EEPROM located inside the memory compartment (yay, no disassembly required!). For the T21 I went through the trouble of soldering on the wires to the SDA and SCL pins of the EEPROM. Figuring I had a steady enough hand, when it came to the T23 I simply held the two wires spaced apart exactly the same distance as the pins and "pushed" them onto the EEPROM. For both systems, I just clipped the ground wire onto the metal tab next to the screw hole for the memory cover. I did get an error message during the read of the T23's EEPROM, but the password that was read and decoded was correct. Not sure what the exact wording of the error was since I ran the IBMPASS2 program and then closed the DOS window just as I noticed the message. I'm still using the MAX232 interface circuit that I built on a breadboard several months ago. It has performed extremely well.

[victor]

I just want to update the bookmarks to Ray's tutorial here:
http://www.rkawakami.net/ibm_600x/max232_if/

A splendid article. Nice work once again, Ray.

[victor]

Here is a small application that could help you with the interface diagnosis.
www.allservice.ro/store/utils/itester.zip

I made this because many users experienced problems in building their devices. It is always better to be sure that the programmer is performing before testing on the eeprom itself.

To find out how to use it see the help window.

Good luck!

Staff Note:
itester has been included in R24RF08 kit. Bob

[me1]

hi, gr8 work to all, Im trying to build what I need to unlock my t43, boy am I learning fast lol, anyone have any photos that may help me also the tester program would be good to try first but link seems to be dead ?

[bob]

The link lives again!
Anyway, the itester is included now with the R24RF08.

[Don]

I am in awe of some of the soldering skills pictured on this site.

My hands may look steady to the naked eye, however, under the magnification needed to see the Atmel clearly...my hands no longer looked steady enough to perform any soldering on the tiny legs of the 14-pin IC and my finest soldering iron tip looked like a baseball bat.

I needed to tap into that Atmel in three places (very temporarily).
I only have two hands and a third hand won’t fit inside the memory door of the T23 TP anyway.
The way to “work around” my personal shortcomings was to make a twin-tipped probe capable of tapping pins 8 and 10 using one hand.

The twin probe was constructed by soldering leads on two sewing needles then using stiff insulated wire to sandwich a strip of plastic (credit card thickness) between the needles. When satisfied with the spacing from tip to tip, I used plastic or household cement to glue everything in place. Not pictured is the heat shrink tubing or rubber vacuum hose used to insulate the lead ends of the needles from your fingers.





Hints: 1. Glue a couple of wraps to one needle first, let dry, then you can get tension on your wire for the final wrap.
2. Use very sharp needles (to buffer the oscillation generated by your personal stress)
3. Borrowing a section of windshield washer hose from wife’s car for insulators...not recommended.

“3-pair” telephone cable was used for all leads and a piece of drop was used to wrap needles.

A separate sewing needle was used for the pin 6 ground connection on the Atmel.

While I held the needles in place and sweated blood... my wife made the lead connections to the SIPROG (ground first) and ran Victor’s program. Success! Sweet!

Many thanks to Victor and all that contribute to and help maintain this very informative site. Any time spent here researching will be well spent and all they ask in return is your eeprom dump.

Don

Staff's note: Picture hosted on allservice.ro as per author's request.
_________________
“Men stumble over the truth from time to time, but most pick themselves up and hurry off as if nothing happened.”
Winston Churchill

[lnd54321]

[victor]

At first sight it looks ok to me. Nice drawing
_________________
Victor Voinea
ALLservice HQ, Romania.

[Raik]

http://allservice.cabspace.com/dl/r40-tutorial.rar <<< link is dead.

my driven circuit deliveres
SDA +4,99 V / +0.68 V
SCL +5,00 V / +0.68 V
but switches booth SDA & SCL as expected.
(image follows)

is this a problem?

[bob]

Link updated.

For driven circuit is normal to have all positive values. But I think you didn't power the circuit with the 3xAA batteries?! Use the batteries, it is much safer, the Vcc have to be up to 5V, but not over.

[Raik]

it is usb-powered. a little resistor may help? or something, to limit the maximum voltage?
better lower booth values, the 0,68V too, or just restrict the Vmax ?

[victor]

Hello Raik,

A resistor will limit the curent and the MAX232 won't work. Use the batteries they provide a true CC that doesn't need to be filtered. USB5V+ usually works but I personally know that this may cause a lot of trouble sometimes so Bob gave you a good advice.
_________________
Victor Voinea
ALLservice HQ, Romania.