ThinkPad from the 755 era with transparent screen

[Int_31h]

Back around 1997 or 1998, there was a ThinkPad whose display's reflective back panel was removable, and the display could be folded down flat with respect to the keyboard. This was intended to place it on an overhead projector as was common back then.

I think it was a ThinkPad 755CD... I know it was a DX4 processor. I am trying to remember exactly what it was and cannot find any information about it online. It belonged to my brother who worked for IBM at the time and it was issued to him as a standard employee laptop for people who worked in Global Services and travelled a fair bit (thus they were issued laptops).

[solidpro]

I think the 755CDV was the only one to be used on overhead projectors. Never seen one in the wild though.

[BillMorrow]

Back around 1997 or 1998, there was a ThinkPad whose display's reflective back panel was removable, and the display could be folded down flat with respect to the keyboard. This was intended to place it on an overhead projector as was common back then.

I think it was a ThinkPad 755CD... I know it was a DX4 processor. I am trying to remember exactly what it was and cannot find any information about it online. It belonged to my brother who worked for IBM at the time and it was issued to him as a standard employee laptop for people who worked in Global Services and travelled a fair bit (thus they were issued laptops).

see above post from solidpro who is correct..
ibm made only this one 755CDV.. i had one and sold it for over $5k at the time..

NOW, please edit your account and enter your correct location..
thank you

[ThinkDan]

We had a 755CDV at the HelpCentre, it was a fun toy and of course OHPs were in every meeting room back then so it did have a genuine use. Identical to a 755CD but for the screen arrangement. From memory one unique extra in the box was a velcro strap to prevent it toppling off the OHP! ETA: the HMM lists a strap, a stand, and a remote control for the V variants.

There was both a 755CDV (thick chassis with CD-ROM/floppy) and 755CV (thin chassis, floppy only), and both were available as either DX4/100 or P75. The screens were all 640x480 TFTs, and properly backlit so comparable in quality to the normal 755C, although not black matrix so not quite as crisp as the 755CD/CE/CX.

Found a screen for one of these in the attic the other day whilst looking for something else. Bought it many years ago as new old stock and filed it away, like you do, due to "when would you see another one?" logic. Sadly it doesn't come with the clip-on outer cover (FRU 85G1630 in case you were wondering), so not a complete lid replacement for another 755. The large metal pads on the rear of the screen will be for EMC shielding, it looks like the illumination is from the side behind those pads.



Thought I'd note it here and then in, oh, about 7 years somebody will be looking for a spare part...

[solidpro]

Can you retrofit this spare part to a normal 755?

At some point in the last few weeks I noticed a website somewhere also reference a 760CDV as well.... don't know if that's true or not.

OHP's were in every classroom when I was in my youth. They've evolved nowadays into interactive projectors displayed on whiteboards or large LCD displays, usually touch interactive doing roughly the same job. I think I once tried to use an OHP to turn a TV into a massive all projected screen. I think it kinda worked.

[ThinkDan]

Have edited the above to say that the large metal pads are for EMC shielding. It was concerning me that if they were contacts for the CCFL backlights then they'd be passing quite a serious voltage, which seems to be asking for an accident. The dimple shown is a button, presumably so the laptop knows when the screen back is removed and to then power off the backlight, but trivial to override manually. Metal plates in laptops is for shielding, I presume that for the usage scenario without the upper case fitted, the emissions were too high.

I've just laid a 360CSE screen over this 755 V screen, and the connectors are different. Hinges too. I have some parts machine 755CE's to hand and will take those apart, I suspect the differences between 360 and 755 V will be common between 755CE and 755 V, meaning no easy interchangeability between 360/370/750/755 and 755CE/CD/CDV/CV/CX.

The 760C panels use different connectors again, so no chance of an easy swap across to a 760. I don't recall this being carried over into the 760 line anyway.

Let me do a bit of dismantling and get some panels laid out on top of each other for photos and it'll be clearer. I'd like to compare the interposers too.

[solidpro]

Are you going to argue with the truth that is wikipedia? https://en.wikipedia.org/wiki/IBM_ThinkPad_760

IBM ThinkPad 760CDV – Similar to the 760CD, this unique model had a removable back cover on the LCD that would permit light to shine through for use on an overhead projector.

[Psyberducky]

I can confirm that removing the back frame of my 755CDV's screen turns off the backlight (which is really more like a sidelight), and the dimple is indeed the switch that controls this. As you said, you can manually press it to turn the backlight on, which looks really weird if you just have the laptop open on a desk, with the back of the screen removed, and the backlight on!

The rear frame/panel is surprisingly easy to snap off and on, just pressing the sides and pulling it is enough to remove it. I never had the Velcro strap though.

Many years ago, I tried swapping the transparent (640x480) 755CDV screen into an 800x600 755CX, and it didn't quite work - the picture was close to correct, but the phase wasn't quite right. I never tried it with my 640x480 755CX (which has a slightly different video card/interposer and no DSP), but I'd be willing to bet that would have worked properly.

[BillMorrow]

WAIT..! what..? 760CDV.. never heard if such a unicorn..! mythical AFAIK.. of course all that IS 25 MOL years ago..
755 series was vastly different from 760 series,,

[solidpro]

I think it's a fact made up by someone on Wikipedia. I could find no other reference to the 760CDV anywhere else on the internet.

[axur-delmeria]

I think it's a fact made up by someone on Wikipedia. I could find no other reference to the 760CDV anywhere else on the internet.

I agree. There's no source cited for the 760CDV at all. And the fact that it's not on any Hardware Maintenance Manual (at least, the ones I've seen anyway) casts a lot of doubt regarding its truthfulness.

[ThinkDan]

Yes, that's what I did - check TWBOOK and the HMM, and saw no reference to such a panel for the 760 models.

This withdrawal announcement from May 1996 shows the 755CD replaced by the 760CD, and the 755CV/CDV replaced by... the 755CV/CDV! OK, I presume it's the DX4/100 model being replaced by the Pentium.

Code: Select all

June 28, 1996, you can no longer obtain these products directly from
IBM.  You can obtain these products on an as-available basis through
IBM authorized remarketers with an approved value add or IBM
Authorized Personal Computer Dealers.
       Affected Product Information:  The following machine types are
affected by this announcement:  2524, 2620, 2625, 2630, and 9545.
Refer to the PRODUCT WITHDRAWALS section for applicable models.
       Replacement Product Information
                                                            MACHINE
WITHDRAWN PRODUCT             REPLACEMENT PRODUCT           TYPE
ThinkPad (R) 755CD            ThinkPad 760CD                9546
ThinkPad 755CV/CDV            ThinkPad 755CV/CDV
                                (Pentium)                   9545
ThinkPad 730T                 ThinkPad 730TE                2524
ThinkPad 755CX                ThinkPad 760L                 9547
ThinkPad 360PE                None
ThinkPad 365C/CS/CD/CSD       ThinkPad 365E/ED
                                (5x86)                      2625
ThinkPad 701C/CS              ThinkPad 560                  2640

Interesting comment here from an IBM reseller who appears to have been notified around March 1996 that a 760CDV was planned for Q4 1996, but it never seemed to have materialised.

Remember these things?



Effectively a backless LCD monitor that you overlaid on an OHP, connected via a VGA cable as an external monitor. Much more flexible because any laptop/computer with a VGA out could drive the presentation. Although I'm sure this was also a costly add-on, the flexibility of either taking on on the road or keeping one in the boardroom for any and all uses would surely have challenged the costly premium laptop screen option, and of course the upgrade path (e.g. for higher projection resolution) would have been to simply replace the flat panel, not umpteen laptops. 640x480 was old hat even in 1996, with the 760C/CD arriving with 800x600 panels and the similar resolution 755CX already on the market. We forget how quickly some of these technologies and features progressed, making last year's premium product seem slow or clunky compared to this year's premium product.

This '3M LCD Projection Panel Model 6050' has 800x600 resolution, not sure when this was introduced but both it and 1024x768 variants were available by 1998. More info and pictures here.

[dr_st]

I think it's a fact made up by someone on Wikipedia. I could find no other reference to the 760CDV anywhere else on the internet.

I agree. There's no source cited for the 760CDV at all. And the fact that it's not on any Hardware Maintenance Manual (at least, the ones I've seen anyway) casts a lot of doubt regarding its truthfulness.

I found only this:
https://discmaster.textfiles.com/view/1 ... TPGALL.TXT

Most likely a mistake, or indeed it was planned and never materialized.

Shall I remove the mention in Wikipedia as erroneous?

[solidpro]

I found only this:
https://discmaster.textfiles.com/view/1 ... TPGALL.TXT

That's really spooky that the 760CDV is mentioned on IBM's own disk. But probably was an idea for about 5 minutes that went nowhere. Yeah, I'd remove it..

[dr_st]

That's really spooky that the 760CDV is mentioned on IBM's own disk. But probably was an idea for about 5 minutes that went nowhere. Yeah, I'd remove it..

Done.

[ThinkDan]

Most likely a mistake, or indeed it was planned and never materialized.

Yes, the chronology is odd, no mention of a 755CV or 755CDV and the 760CV / 760CDV were added before the 760C etc.

I checked another mirror and found v3.02 of the same file, from April 1997, vs the v3.01 from Oct 1996 that you had cited - in the later file, the v1.20 comment has been corrected to remove the reference to the 760CV and 760CDV.

Code: Select all

Released Versions
-----------------

Version   1.00     Initial release for ThinkPad 755CE/CD
          ...
          3.01     Documentation change
          3.02     Documentation change
          

Summary of Changes
------------------
...          
<1.20>
 - (New) Support for ThinkPad 755CX, CV, and CDV.
 - (New) WIN-OS/2 support.
...
 

[axur-delmeria]

Remember these things?

I've never seen those in the flesh, but have seen the magazine ads. Also, partially-disassembled LCD panels and OHPs were the usual starting points for DIY video projectors.

[BillMorrow]

a typo, later corrected..?