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Thinkpad 750CS Questions

R

Raven

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I am currently planning on purchasing a Thinkpad 750CS from another forum member here to use as a DOS gaming and dev machine. I know from experience that a 33mhz 486 is good enough to run any of the games I want to play on it (I played them all [albeit without sound] on a 25mhz 486SX T4400C in the past - it died :/).

It has a CS4248 chip for audio, which I believe is SB-compatible, but I've had some bad experience with non-true soundblaster chips. Keep in mind I don't care about audio "quality", just as long as it plays back both digital sound effects and Adlib/FM without skipping one, the other, or both (I've had some cards refuse to play digital sounds but do Adlib fine while claiming SB compatibility).

The video card is my other worry. I've used lots of this era of WD cards, and they usually work fine, but my T6600c refuses to properly do VESA. It took a long time to find a VESA driver that would recognize it correctly and then be recognized itself by games. Once I managed that the bottom third of the screen liked to alternate between mirroring the top third, being blank, and being correct. Needless to say that didn't work out for me for VESA games.

I'd like to hear what you guys have to say about this era of Thinkpad's compatiblity with DOS games, VESA, and SB. Any success stories, horror stories, etc. related to this and similar models, or even the same chips.

Thanks.

Edit: Oh, and it has a PC speaker... right? I don't think my T6600C does, and it's been bothering me.
 
I didn't check my messages until recently. I haven't found the time to mess with my 755CD much, but if you still need help, I can look into specific things for you.
 
Wow that's a late reply, hah. I'm not looking into one at the moment, but haven't filled the gap of a portable DOS machine, so if you could test the following for me it would be appreciated:

- Does it have PC speaker sound? (I use Cosmo's Cosmic Adventure to test this - all sound effects are PC Speaker, music is Adlib)
- Is it truly SB-compatible? (I use Monster Bash as my benchmark for this, as it's relatively picky - the sound effects in particular)
- Will it run in VESA modes properly? (Stargunner and Master of Orion 2 are the games in question for me)

If you can't/don't want to test this stuff that's fine - I understand (I'm quite lazy, lol).
 
I can provide a few observations from my own 755CD, for what they're worth:

As far as SB compatibility goes, it's generally ok. Certain games that make exotic use of MIDI might not work perfectly. Ex: IndyCar Racing apparently uses MIDI for tire skid SFX, and it ends up sounding like scratching rather than skidding.

VESA seems to run okay, though gaming at 640x480 isn't the best on a sub-Pentium 133MHz system. My 755CD has a 75MHz Pentium and it's pretty choppy when running Wing Commander III in VESA. It runs Nascar racing in VESA like a slide show unless all textures are turned off.

320x200 games that make standard use of audio will probably run fine. Just bear in mind that since 320x200 is a non-square pixel mode, most of these games will look slightly squashed on the laptop's LCD.
 
I'm having a tough time getting the files onto a CD that can be read by the CD-ROM drive in the Thinkpad, but it does sound like it has a PC speaker (albeit a tiny, high-pitched one, probably unsuitable for game sound).
 
I've actually owned quite a few 486 and Pentium class Thinkpads specifically for DOS gaming.

IIRC, the CS4248 audio chip TOTALLY SUCKS. It actually emulates the SB with a software driver, and the driver doesn't work in 32-bit protected mode. So while the card will work fine in Wolfenstein 3-D or Monkey Island, for example, it won't work at all with games like DOOM and TIE Fighter.

Also, you'll want to avoid Dual-Scan LCDs (anything with a "cs" suffix as opposed to "c"), as they are terrible for fast-scrolling graphical applications (i.e. games). A lot of the lower end 486 Thinkpads had these. I'd even recommend a Monochrome Thinkpad over one with a DSTN.

I remember the 750C and 755C having the Crystal audio/modem combo cards. Plus, most of the 755's and none of the 750's came with a CD-ROM drive, so you'll have to attach them to a Thinkpad Dock I or Dock II for an optical drive. I had a Dock II, and it was really neat because it had 2 ISA slots, a built-in SCSI adapter, and a 5.25" drive bay.

I'd recommend the 755CD or one of the 760 series. This is when IBM started using the MWave audio/modem combo, which had a driver that actually worked in 32-bit mode. http://www.thinkwiki.org is a good resource for the entire Thinkpad series, from older vintage machines to the newer Lenovo ones.

Too bad I didn't know you're looking for an old gaming Thinkpad when I went down there to trade parts, I'm actually trying to get rid of one that's in good shape. :p
 
Also I vaguely remember having trouble with VESA modes. I know I couldn't run the TIE Fighter Collector's CD in 640x480 mode, but it ran okay in 320x200.

I think DeeP (an old DOOM map editor) ran okay in 640x480x256, but wouldn't work in higher resolutions.
 
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