VOGONS


First post, by Intel486dx33

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The mailman brought a package today.

It’s an IBM 755cse with SelectaDock and Sound Blaster 16 ISA card.
It is almost intact just missing the SelectaDock keys, and bottom speaker cover and back cover.
Otherwise it all there.

So I opened it up the top lid to the 755 and found that the battery has started to corrode so I pulled it out.
This is a common problem with these old Thinkpads and a known cause of failure due to the corrosion getting
On the circuit board PCB.

But this Thinkpad still boots but it has a bios lock.
I am not worried about that.

I have a couple donors I am going to use to build a good working one.
I actually only need the TFT Display. But will will see what other parts I can use to build a good working one.
I really like this Multimedia SelectaDock because it has built in speakers, ports, and CDROM.

I think this was IBM’s first Multimedia computer.

First thing I am going to do is take this to a locksmith and get a key made for the SelectaDock.
Then I need to clean up this computer.
The rubber has begun to melt and gets all over my hands when I touch it.
How can I clean off all this disintegrating rubber?

This guy has a nice resource page about the thinkpad 755cse
http://oldcomputer.info/portables/tp755cse/index.htm

Manual
https://manualsbrain.com/en/manuals/1199222/?page=441

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Last edited by Intel486dx33 on 2020-12-01, 04:02. Edited 4 times in total.

Reply 1 of 13, by Intel486dx33

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More photos

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Reply 2 of 13, by Bondi

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You made a great deal.
I also have this docking station with TP360CE or 760LD attached to it. And this is an excellent setup for DOS gaming.
The only downside of your 755CSE is the DSTN screen, as you already mentioned. It also has MWAVE based sound card, according to Thinkwiki. Is it indeed the case? From my experience MVAWE it works okay, but I'd disable it and install a proper sound card with MIDI DB in the ISA slot inside the dock.
It may also be tricky to find the CD-ROM for it. I bought the installation kit (66G3536 ) for mine on ebay, but see none available now.

There is a very nice thread about this device - 486 Thinkpad with genuine Sound Blaster Pro 2

Reply 3 of 13, by Intel486dx33

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Bondi wrote on 2020-04-27, 16:14:
You made a great deal. I also have this docking station with TP360CE or 760LD attached to it. And this is an excellent setup for […]
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You made a great deal.
I also have this docking station with TP360CE or 760LD attached to it. And this is an excellent setup for DOS gaming.
The only downside of your 755CSE is the DSTN screen, as you already mentioned. It also has MWAVE based sound card, according to Thinkwiki. Is it indeed the case? From my experience MVAWE it works okay, but I'd disable it and install a proper sound card with MIDI DB in the ISA slot inside the dock.
It may also be tricky to find the CD-ROM for it. I bought the installation kit (66G3536 ) for mine on ebay, but see none available now.

There is a very nice thread about this device - 486 Thinkpad with genuine Sound Blaster Pro 2

I have some questions.
1) When the dock is locked does it also lock the computer screen ?
2) Do you have a link to the docking station manual ?
3) What ISA sound cards work in this dock ?
4) Does Win95 perform okay in this laptop with a 486dx4-100 CPU ?

Reply 4 of 13, by Bondi

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There is no actually screen lock. The lock has 3 positions - left(2) - computer cannot be turned on at all, middle - TP can be undocked, right(1) - can be turned on. So, in the position of your lock it can boot, but cannot be undocked.
http://download.lenovo.com/ibmdl/pub/pc/pccbb … les/dock1ug.pdf - User's guide
http://download.lenovo.com/ibmdl/pub/pc/pccbb … kpad/tpvol1.pdf - HMM
The dock can take any full length and hight isa card with a daughtherboard.
Win95 works acceptable if you have enough RAM. There are videos of 755CD(same CPU) running W95 on YT.

Did you try to remove the BIOS battery to clear the password? There should be 2 batteries, one is standby battery the other one is BIOS battery. If you're lucky it's the boot password, and not supervisor pasword.

Reply 5 of 13, by Intel486dx33

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Yes, I removed the batteries and turned on the laptop.
I received 2 beeps and then it reboots. it just goes in a cycle.
I did not see any lock on the screen however.

I also tried to open the bottom but the key is locked so I could not open the bottom cover.
Can you post a photo of the key. I want to try to have a local locksmith make a key.

Reply 6 of 13, by Bondi

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Do you start it with main battery removed? I had exactly the same problem. Removing the battery did the trick.
Here is the key.

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Reply 7 of 13, by Intel486dx33

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Thanks for your help.
Yes, I removed the main battery and the two other batteries. One was a yellow coin battery and the other was a green battery.
They both look bad with corrosion.
See photo.

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Reply 8 of 13, by Bondi

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Just checked beep symptom table https://download.lenovo.com/ibmdl/pub/pc/pccb … iles/tpvol2.pdf

Two short beeps with blank screen. - 1. System Board

Last edited by Stiletto on 2020-05-01, 04:31. Edited 1 time in total.

Reply 9 of 13, by Intel486dx33

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Bondi wrote on 2020-04-30, 11:57:

Just checked beep symptom table https://download.lenovo.com/ibmdl/pub/pc/pccb … iles/tpvol2.pdf

Two short beeps with blank screen. - 1. System Board

Yeah, I saw that document. It’s almost like for any beeps they quote ( -1. System board ).

I am going to take it to the lock smith maybe next week to get a key made.
Once I get it off the dock I can more comfortably work on it.

Thanks for your help.

Reply 11 of 13, by Intel486dx33

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I have a new donor thinkpad so I should be able to make at least one good one out of these.

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Reply 13 of 13, by Intel486dx33

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Yes, I still have to take this to the local locksmith and get a key made.
I have been putting it off because of the lockdown.
At least I have a working 755 thinkpad.

But I have some new sound cards too.

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