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115 comments
Tube🍂Time replied to Tube🍂Time

I 3D printed a new power connector. the strain relief is printed using TPU.

Darryl Ramm replied to Tube🍂Time

@tubetime Did you have to make your own contacts of could you reuse something else?

Tube🍂Time replied to Tube🍂Time

any ideas about the type of connector the docking port uses? it's like a micro ribbon connector but with four rows instead of two rows. 240 pins total. pin pitch is 1.27mm. the only markings on the connector are "MXJ1" at one end and "52577A" at the other.

Tube🍂Time replied to Mark J Koch ✅

@maehem yeah i sorta think its a Hirose product but it's not DXM, which has only 2 rows of contacts, not 4.

DrYak replied to Tube🍂Time

@tubetime and apparently that specific one is only found on 700 and 720 series.
Source: thinkwiki.org/wiki/Docking_Por

Probably this one is ISA only, whereas the following series have PCI and/or CardBus.

Tube🍂Time replied to Tube🍂Time

i figured it out. it is the AMP .050 CHAMP line of docking connectors.

Tube🍂Time replied to Tube🍂Time

oh i should fix the backlight, which blinks on and off for some reason. time to take it apart!

Tube🍂Time replied to Tube🍂Time

welp, looks like i missed a few electrolytic capacitors. check out all that nasty corroded fuzz on the nearby component leads!

Tube🍂Time replied to Tube🍂Time

all cleaned up! i had to remove all those parts, add flux and reheat all the pads, scrub with IPA, and then put everything back in place. and replace the caps, of course.

Tube🍂Time replied to Tube🍂Time

it lights up and stays lit, so i'll call that a win. (yes, the hard drive still isn't working, so it's not booting.)

Tube🍂Time replied to Tube🍂Time

i just got the AC adapter for this! it came in from everyone's (not) favorite auction site. the listing conveniently forgot to mention that it REEKS of cigarette smoke. 🤢
oh well, at least it was cheap.

Tube🍂Time replied to Tube🍂Time

even the inside smells like smoke. it's not an ultrasonically-welded plastic case (just held together with 4 screws hidden under the labels) so it's definitely not airtight.

Tube🍂Time replied to Tube🍂Time

pulled the main power transformer for reverse engineering purposes.

Tube🍂Time replied to Tube🍂Time

last night i reverse engineered it. the design is simple so it wasn't too hard. the files are here: github.com/schlae/Thinkpad700C

Tube🍂Time replied to Tube🍂Time

it also explains the mystery "INPUT SIGNAL" pin on the old 4-pin IBM Thinkpad power connector. this pin simply increases the output current limit when it is pulled low by the laptop. it's because the power brick is also the battery charger, and when the laptop is turned on, you have to increase the current to compensate.

Tube🍂Time replied to Tube🍂Time

anyway, isopropyl alcohol wipes and a bath in Simple Green has mostly taken care of the bad smell.

Tube🍂Time replied to Tube🍂Time

now for that pesky docking connector: I've discovered that a 1.2mm PCB fits perfectly in the connector, so I made a set of two boards that stack and break out all the pins to 0.1" headers.

George Laskowsky replied to Tube🍂Time

@tubetime Please don't step on those! Lego is bad enough already

math blasterson replied to Tube🍂Time

@tubetime Haha, that was actually my first thought when you started this thread. "Those are just dressed up card-edge connectors." Nice job.

Tube🍂Time replied to Tube🍂Time

now you know why I need a working logic analyzer. these pins also go to the hard disk connector inside, which makes me think they are the internal bus. the trick is to figure out what they do.

Dustin replied to Tube🍂Time

@tubetime holy smokes you are really deep-diving on this one, well done!

Tube🍂Time replied to Tube🍂Time

next step is to identify control lines vs address and data

DrYak replied to Tube🍂Time

@tubetime when you manage ti document it, you're probably going to make a few hardcore ThinkPad fan happy.

Expect retro OPL2/3 sound card and joystick ports to appear.

Tube🍂Time replied to Tube🍂Time

starting to pick out a few lines. between the cursors is an extended bus cycle

Tube🍂Time replied to Tube🍂Time

now I'm writing short programs in DEBUG to help me figure out which data lines are which.

Tube🍂Time replied to Tube🍂Time

i've got all the address and data lines mapped out, and all the basic control lines. now to figure out the DMA lines...

Tube🍂Time replied to Tube🍂Time

and that's 99% of it figured out. i haven't untangled which IRQ is which, and there are a small number of signals i don't understand yet. but this is functional enough to start building adapters. i'll publish this at some point.

Tube🍂Time replied to Tube🍂Time

there are a few signals unique to the hard drive connector, so I'm figuring those out now.

Tube🍂Time replied to Tube🍂Time

the unique signals are the card setup line (turns out this is slot 1 and the dock connector is slot 2), the high address bits predecoded, IDE style, and what seems to be a system reset line.

Tube🍂Time replied to Tube🍂Time

the hard disk drive has a weird 60-pin AMP CHAMP connector (5176376-2) but that just gets wired to a 52-pin 2mm header. the pin wiring is 1:1 except for the last 8 pins which are not connected.

Tube🍂Time replied to Tube🍂Time

it was surprisingly hard to figure out that AMP part number, btw. connector manufacturers constantly scrub all information about old products because who knows 🙃

Tube🍂Time replied to Tube🍂Time

and yes, the hard drive is vaguely like IDE but it uses the Micro Channel bus instead of ISA. IBM called it DBA (direct bus attach) ESDI. this drive uses the POS ID code DF9F.

Tube🍂Time replied to Tube🍂Time

i needed to figure out which interrupt lines were which, so i wrote a quick and dirty program to detect when an interrupt fires. then i manually triggered them by grounding each pin in turn.

George R. M. 🇩🇪🇺🇦 replied to Tube🍂Time

@tubetime for a second there I forgot these use the aptly-nicknamed "ThinkPad 700 drive". What a cursed thing it was, DBA-ESDI 2.5".

Glen Akins replied to Tube🍂Time

@tubetime My guess would be acquisitions and not caring about all the product lines of the acquired company. Good news is now that TE owns all connector manufacturers*, they won't have this excuse going forward. (*slight exaggeration)

Brad Bell replied to Tube🍂Time

@tubetime I like how they keep making the connector but change the names and numbers

bitsavers.org replied to Tube🍂Time

@tubetime

I started archiving catalogs from connector companies just because of that problem.

Jeff Haluska replied to Tube🍂Time

@tubetime Haven't seen somebody do that in about 25 years.

Jeff Haluska replied to Tube🍂Time

@tubetime Time to invent a rubbing alcohol pressure washer.

ĸurth replied to Tube🍂Time

@tubetime don't say 'just screws' … bless the screws

FozzTexx replied to Tube🍂Time

@tubetime I once got something that was so bad that the things inside that were still sealed in the original shrink wrap reeked of smoke when I took the shrink wrap off. I ended up throwing away most of the items.

Jeff Haluska replied to Tube🍂Time

@tubetime You're taking good care of the capacitors they're growing in size! 😆

Joe Pasqua replied to Tube🍂Time

@tubetime Now that would be a truly useful AI - upload a picture of a connector (perhaps with a ruler for scale), and it tells you what the connector is and where to get it.

Yours was a tough one, but its hard even for more common connectors. Next time I go to Anchor I’m going to take some stuff with me to see if I can find matching connectors.

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