IBM T41 T42 RS232 output trick

[pishta]

Do me favor and ohm out your working DB-9 to see if there are any shorts between any two pins that may not be service affecting. I picked up shorts on many of the max chips leads prior to doing any soldering and i didnt use flux yet, my bad but in my defense i was doing it on the dashboard of my truck on my lunch break, soldering iron plugged into 70W inverter :-)
On that schematic, i dont know where the lines go to once they leave the chip. Potential designed shorts on mobo?

[malch]

There are no shorts on the db9 pins. I will send you a pdf schematic of the T42. I use a Fluke digital meter.
If all else fails desolder the wires and start again. page 47 and 55

[pishta]

I have a T40 but ill look again this weekend under some good
Iight and some 5X goggles, thanks. I have no solder or flux on it now. Will tone out max chip leads onboard and report. Pretty much the entire left side 15-28 had continuity between each other as i recall but ill test again.

[pishta]

After further review, and using sharper probes, i determined i had no shorts off my max chip and was able to wire 5 thin leads out of a keyboard cable onto the docking traces under the tape to a db9 socket that i installed in place of the vga port. I took the entire ribbon cable out from the socket of the vga port and found out this actually cured my cdrom issue of not reading discs of all things! The 5 wires braided together just fit the channel where the vga ribbon went but i had to clip the small piece of plastic that was at the end of the plastic frame next to the screw hole for clearance. The tape lays over my solder joints and the battery keeps the tape down. Very successful modification. I am suprised IBM did not offer a serial port here as an option as they would have the ability to use the vga ribbon socket as a 'versatile' socket depending on what ribbon cable you used as the vga and serial are close enough physically to fit in the frame under the hinge

Big thanks to Malch for the docking port pinouts and the attention to this thread.

[ravex]

Hello, what kind of soldering tool have you guys used to make this job done? I am using a soldering device for electronics with a micro tip, but the PCB is still soo freaking small! Man, everyone who has successfully finished this is a soldering master to me. I am exceptionally curious about the guy who claims that has done this during his lunch break on a dash board of his truck!!

Any advice appreciated.

[malch]

geser is the Master Solder Technician. Here is a site that will help. http://www.aes.org/sections/pnw/solder/tools.htm
You have to use a soldering iron with replaceable tips. You need a conical with a very sharp tip.
As for the truck, ask pishta.

[ravex]

geser is the Master Solder Technician. Here is a site that will help. http://www.aes.org/sections/pnw/solder/tools.htm
You have to use a soldering iron with replaceable tips. You need a conical with a very sharp tip.
As for the truck, ask pishta.

my boss has finished the job today, after all. we used a home-made soldering station with a sharp tip, RS-232 w/ wires from a scrap PC and lot of patience. Here are few pictures from that T42. We're going to try it out tomorrow.

Greetings from Czech republic


DSC02768.JPGDSC02773.JPGDSC02776.JPG

[bigoneoszi]

Thanks!

[arasss1979]

hello if someone of you know whether after this transformation to connect the car for gas installations is still needed interface and whether it is enough to just lead 2 cables RXD and TXD sorry for language
help does not work for me, please

[arasss1979]

nobody knows

only I need the same rxd and txd to connect to the lpg control panel I have led these cables here ... and here the stairs start because something is not working and I do not know if this is how it should be. after connecting these two cables in the hyper terminal, an echo arises as I turn on the program from the lpg installation, the connector 2 rxd and txd cables that pops up already connected to the program but after all I did not connect to the installation ..
secondly, when connected via the lpg installation interface it is the same with nothing working
I am asking for a hint where to look for a mistake

[arasss1979]

nobody knows nothing

[dolbytron]

Anybody confirmed it to work without any issues?

[caitomdq]

thanks

Hello to all member's of DK.
After I need RS232 for autodiagnostic and haven't it on my IBM T42 I was look for tipe hov to output it without docking station... And I was spend a lot time tofind schematic diagram of T41 , T42 Apolo 9 mainboard ( Apolo 9 is code name for MB on T41 and T42 ).

Here is what you need :

For all who need COM1 on IBM T41 and T42 it can be put out from Mainboard of laptop.
Look for MAX3243C on MB. It is RS232 transceiver located on MB but it's I/O are
only on dock station connector ( 245 pin HUH...).
I was success output direct from MAX3243C COM1 with cable and work 100%.
U need good solder and time and magnifier too ;-)

Here are PDF files of MAX3243C and laptop schematic of RS232 COM1.
ALso you need to enable COM1 in BIOS setup.
The chip MAX3243C is located on MB bottom on memory socket inside laptop.
You must remove keyboard and inside memory module.
Better disasemble MB of laptop ( if you have time and know to do that...).

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If you find is good for you please push THANKS .
Sorry for my bad English.

Best regards to all on DK

thanks i tri to use this, i lokin for solucion , i need to program ham radios