VOGONS


First post, by pixelatedscraps

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I finally got my hands on my Thinkpad 755CX today, after several weeks of shipping domestic within US before being forwarded to my current home in Hong Kong.

The power supply (a new Yustda unit from Amazon) and laptop arrived on the same day coincidentally so it was a good day of unboxing. This is one glorious looking chunky laptop.

I believe there are two batteries to check on the motherboard - the CMOS and a backup, if I’m correct. Then the issue is with a likely dead battery that might be swelling one day. HDD, FDD (potentially look for a working CD-ROM drive) - all things to check and test.

What else should I be doing in order to avoid damaging it? And is there a specific order I should be doing them in? I have yet to turn it on as I suspect I should check battery leakage first.

Thanks in advance, gurus. Will post photos tomorrow.

Links that have helped immensely with information specific to the Thinkpad 755CD/CX:

Official 755CD OS/2 Museum
http://www.os2museum.com/wp/ibm-thinkpad-755cd/

Official IBM Thinkpad 755CX Press Release
https://www.ibm.com/common/ssi/ShowDoc.wss?do … -131/index.html

The Official 755 Upgrade & General Info thread at forums.thinkpads.com:
https://forum.thinkpads.com/viewtopic.php?t=123592&start=60

Drivers & BIOS
http://ps-2.kev009.com/pcpartnerinfo/ctstips/b236.htm

Main battery replacements
https://www.abeststore.com/laptop-battery-md. … +laptop-battery
https://www.power-supplier.co.uk/laptop-batte … Pad%20755CD.htm

Official Part Numbers:

Li-ion battery
85G8554

Ni-MH battery
85G1510

CMOS Battery
NiCD FRU85G1038 / FRU85G1039

HDD
82H8489

CD-ROM
73H9983

FDD
66G5060

Last edited by pixelatedscraps on 2022-01-12, 12:20. Edited 9 times in total.

My ultimate dual 440LX / Voodoo2 SLI build

Reply 1 of 14, by keenmaster486

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Yeah both of those batteries are most likely dead, and should be replaced.

What about the main battery? Do you have that? If you do, it will probably need the cells replaced in order to work again.

Otherwise I wouldn't worry about damaging it. You can probably just turn it on and use it for now.

World's foremost 486 enjoyer.

Reply 3 of 14, by pixelatedscraps

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First pics from opening up and upon closer inspection, it is a 755CX model (https://www.ibm.com/common/ssi/ShowDoc.wss?do … -131/index.html). This makes me simultaneously happy in that the CX are Pentium models which means Li-ion batteries are standard or compatible but equally disappointed as I was hoping for a DX4-100 unit. Let's see though, as the initial inspection prior to boot up shows that the included battery is indeed a Ni-MH unit.

Visually the unit is in great condition for its age - the seller was indeed telling the truth. However there appears to be a missing piece of plastic from the FDD covering (cracked / fell off but no other signs of a fall) and the lock tab on the bottom plate seems to be missing. Other than that, the unit is in really quite excellent condition - and the LCD panel is superb (wonder if its been replaced before?).

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Last edited by pixelatedscraps on 2021-08-25, 08:48. Edited 1 time in total.

My ultimate dual 440LX / Voodoo2 SLI build

Reply 4 of 14, by pixelatedscraps

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And to the insides...

It looks like an early 1996 model with a Ni-MH battery. The HDD is missing and I do not have a replacement for it yet so it'll be a while until I can really get to tinker with this yet. I'm very curious to see if this boots into BIOS or not.

The main battery seems in good condition, as does the CMOS and backup battery - there doesn't seem to be any leakage or corrosion at all. Does this mean I can power it on safely?

I'm scouring the web for the needed NiCD CMOS battery FRU 85G1038 / 85G1039 battery and have found the following sellers. If anyone else is trying to bring back a 755CD / 755CX to life, perhaps this thread can help in some way:

https://www.tamayatech.com/parts.php?g=85G1039
https://www.itpartshelp.com/batteries/ibm-bat … 85g1038-85g1039
http://indexcomputer.com/battery/85G1038.html and http://indexcomputer.com/battery/85G1039.html (not sure why there are two separate ones listed with this seller)

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My ultimate dual 440LX / Voodoo2 SLI build

Reply 5 of 14, by pixelatedscraps

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Diagnostics run well and everything that can be tested, passes. I'm amazed at this. Along with the visual condition, this makes me wonder if this machine has been recently used / restored or was a lightly used machine over its lifetime. Or it was a spare CX that was used for parts - hence the Ni-MH, FDD and missing HDD (CX defaults were Li-ion, CD-R and 1.2GB HDD).

Once all the tests have passed, I adjust the date and time and switch off the laptop and remove the power plug; an easy thing to do seeing as the Yustda plug is not a secure fit - more on that later.

Amazingly, upon boot up the BIOS date/time settings reappear - it could just be I have some juice left in this CMOS / backup battery combo. Nonetheless, a replacement will be ordered for backup's sake.

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My ultimate dual 440LX / Voodoo2 SLI build

Reply 6 of 14, by pixelatedscraps

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I've updated the initial post with links to several sites where I've managed to find original press releases, BIOS and drivers and also spare part numbers and battery links. Should any 755CD/CX owners stumble across this, it might be a useful starting point.

My ultimate dual 440LX / Voodoo2 SLI build

Reply 8 of 14, by drosse1meyer

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Congrats. I had one a long time ago (2000-ish) , someone gave me the 75 mhz version with the pentium bug 😀

I loved the keyboard and how it hinged open and had such easy access to the add ins.

Since it was pretty slow for window98+ decided to put linux on it. We were able to get slackware working along with a pcmcia+dongle but it was a pita iirc although a good experiment. IDK what eventually happened to it but I imagine I left it at my parent's house and got tossed 🙁 One of the things I wish I still had.

P1: Packard Bell - 233 MMX, Voodoo1, 64 MB, ALS100+
P2-V2: Dell Dimension - 400 Mhz, Voodoo2, 256 MB
P!!! Custom: 1 Ghz, GeForce2 Pro/64MB, 384 MB

Reply 9 of 14, by stamasd

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I've had one of these since the mid-1990s. It was my first laptop. Still works fine, with Windows 95.

The main battery is dead of course, and my multi-year quest to find a replacement has failed. I have bought over the time several "new" or "NOS" batteries, but all of them ended up being just as dead. These haven't been manufactured for over 20 years. I also tried replacing the cells in one with new cells, that failed also.

If you can find one, a Dock I http://www.thinkwiki.org/wiki/ThinkPad_Dock_I_(3545) or a Dock II http://www.thinkwiki.org/wiki/ThinkPad_Dock_II_(3546) are worthy upgrades. They add a lot of goodies, including ISA slots that you can use for upgrade cards. I have one of the Dock II and it's glorious. It adds 2 full-size ISA slots as well as SCSI controller, and has bays for adding HDDs and/or CD drives.

One thing that you won't be able to do without a fully charged battery, is update the BIOS. The IBM bios flasher checks for a fully charged battery and refuses to function if it doesn't find one, even if the Thinkpad is plugged in. And by fully charged, I mean the battery needs to be at 100%. (99% won't do). I don't know what the IBM engineers were smoking when they decided to put that requirement but it must have been strong stuff. It's pretty much impossible in this day and age to meet it. That was in fact the main reason for my search for batteries - mine has an older version of the BIOS that has a bug which prevents it from having sound in Win98. I have the latest BIOS file but cannot flash it. 🙁 I have heard rumors that back in the 1990s someone hacked that installer to remove the battery requirement, but I have been unable to locate the hacked file.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 10 of 14, by stamasd

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Also, for the HDD you need a caddy. Caddies for the 755 series and the 760 series are compatible (same dimensions and same connector). Standard 2.5" IDE drives fit inside the caddy. I'm not sure what the maximum size is, but mine has a 2.1GB drive so it's at least that. Last I looked (a few years ago) there were caddies with or without drives on ebay for anywhere between $15-30 USD. CF cards with CF/IDE adapters work as well inside a caddy.

(edit) this seems to be the cheapest right now https://www.ebay.com/itm/264937906411?hash=it … Campid%3APL_CLK

Last edited by stamasd on 2021-08-25, 16:46. Edited 1 time in total.

I/O, I/O,
It's off to disk I go,
With a bit and a byte
And a read and a write,
I/O, I/O

Reply 11 of 14, by Intel486dx33

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I have 3 or 4 Thinkpads 755 and I think I can make 2 good working ones out of these. Well I know I have two good working ones.
Maybe I can make 3 good working ones.

What I really like is the Dock. Which has a CDROM drive and supports an ISA sound card.

Reply 12 of 14, by pixelatedscraps

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I've got an original UK-pronged IBM power adapter, a replacement original TEAC CD-ROM in its caddy and an original 2.1GB IBM HDD in its caddy on its way. The HDD is not in the greatest condition but it only cost me $18 and at least I'll be able to swap in a new HDD, SSD or CF card into the caddy if need be. Fingers crossed the CD-ROM is working!

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My ultimate dual 440LX / Voodoo2 SLI build

Reply 13 of 14, by pixelatedscraps

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It works! And with someone else’s HDD and Windows 95 installation, too 😉

All original non-leaky, no-bulge batteries and someone else’s original Thinkpad charger.

I had purchased the original IBM / TEAC CD-ROM drive before realising this was a 755CX - which doesn’t accept a CD-ROM drive. A bit unfortunate, but I have my eye on either a 755CD or period correct external CD-R drive.

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My ultimate dual 440LX / Voodoo2 SLI build

Reply 14 of 14, by pixelatedscraps

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I've posted this over in the huge Bought these (retro) hardware today thread but I'll update here as well.

A 755CD in great condition just arrived earlier today. First few boots were successful and I then set about looking to format and reinstall Windows 95 on the machine. When booting into DOS, I notice the CD-ROM drive is no longer detected. I check the BIOS and set to defaults again before booting and running all the diagnostic tests; a screenshot is attached below.

It may take a couple of days for me to troubleshoot but I'm wondering if in booting up the machine several times, I've woken some long-stirring bugs and something is now failing on the mainboard. My reference material is http://ps-2.kev009.com/eprmhtml/epr2a/h4159.htm but it's getting late and I'm kinda stumped. The seller did mention he had removed the batteries (backup power as well) as he had started to notice them leaking. Could it be that and if so, what should I do to avoid further damage and is it possible to repair whatever issues may have been caused by leaking battery acid?

A shame as the unit is in beautiful condition for its age and I had even managed to install GTA 1 before the CD-ROM failed on the next boot. Just fyi, I did try a spare CD-ROM drive I have and that was also not detected.

Error codes are below if anyone can add or assist, any suggestions would be much appreciated!

Mainboard
DEV 103
ERR 15
FRU 1810

Display
DEV 051
ERR 10
FRU 0041

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My ultimate dual 440LX / Voodoo2 SLI build