ajacocks wrote on 2025-03-01, 01:02:

Their reliability was about the same. And yes, there was a Linux on Laptops page for the Winbook XP5, because I used it for reference when installing Linux on the machine that I kept.

- Alex

Got it, thanks so much for the info on these. Definitely confirms the suspicions I had.

3lectr1c wrote on 2025-03-01, 16:17:

PcBytes wrote on 2025-02-28, 22:49:

One thing I've found about Chicony's MP989 and 983 - it's by far the only laptop series to use Award BIOS. You read that right - desktop Award BIOS 4.51 is what these things use.

Yep, indeed, Award BIOS! And nice find with that MP989 - those are absolutely elite Pentium II desktop replacements. Super cool machine.
Award was found from time to time on some 486 laptops - Nan Tan mainly. You don't see many Pentium or newer Award laptops though.

Thanks. I have a Maxdata branded 989 to order soon. I definitely want to own one and it's hard enough to find any.

Ah, nice. Maxdata was also the only company to sell the MP-999, which was a slightly modified version of the MP-989 that supported Pentium III processors. This was Chicony's last laptop. They're hard to find though.

megatron-uk wrote on 2025-02-28, 13:13:

Got another Compaq Armada 1750 on its way.

It's another 14" screen model, this time with a PII 366 and the full set of drives. Needs a replacement CMOS battery (3v lithium cr3032, 1.25mm jst header).

Hopefully the power supply won't give up like the last one.

Huh, it was the PSU that died? I got a Compaq Armada 1700 pretty recently and as far as I can see it's pretty robust and there's no NiMH to ruin things.

The RTC battery is a standard CR2032, but personally I just take those apart now and use my little powerbank spot welder to connect up a fresh CR2032 battery.
Hopefully your experience goes a bit better this time and lasts a bit longer - the Armada 1700 / 1750 speakers in the palm rest are something special in my opinion, FM audio on those sounds really awesome.

Thermalwrong wrote on 2025-03-02, 00:53:

Huh, it was the PSU that died? I got a Compaq Armada 1700 pretty recently and as far as I can see it's pretty robust and there's […]
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megatron-uk wrote on 2025-02-28, 13:13:

Got another Compaq Armada 1750 on its way.

It's another 14" screen model, this time with a PII 366 and the full set of drives. Needs a replacement CMOS battery (3v lithium cr3032, 1.25mm jst header).

Hopefully the power supply won't give up like the last one.

Huh, it was the PSU that died? I got a Compaq Armada 1700 pretty recently and as far as I can see it's pretty robust and there's no NiMH to ruin things.

The RTC battery is a standard CR2032, but personally I just take those apart now and use my little powerbank spot welder to connect up a fresh CR2032 battery.
Hopefully your experience goes a bit better this time and lasts a bit longer - the Armada 1700 / 1750 speakers in the palm rest are something special in my opinion, FM audio on those sounds really awesome.

Yes, I'm pretty sure it was power related. The last one spontaneously rebooted while sitting at the xp desktop and the LCD no longer powers up and all the keyboard and system indicator LEDs stay lit. CDROM 'pulses/seeks' continuously. It's like it doesn't have enough current or is stuck in reset.

I've tried soldering tabs on to cr2032s before and it was always a mess! Easy enough to get a replacement though.

Yes, the sound quality from those speakers was really very good!

You've got to spot weld tabs onto those batteries, a soldering iron either won't work or will fry the battery with heat.

Yes, it's easier just to buy cr2032s with tabs or jst-terminated leads on already!

Got a PMD-5500 Pentium-90 laptop with a TFT display and CS4123 sound chip with an OPL3 FM synthesizer on it. It boots to strictly DOS command and I was able to copy game files over to the 810MB IBM hard drive. The downside is the stretched display with DOS games and I couldn't find anything in the BIOS to disable that.

If anyone can modify the BIOS for the laptop to have that feature, HMU. I'll get the BIOS from the chip onto a file.

megatron-uk wrote on 2025-03-02, 08:32:

I've tried soldering tabs on to cr2032s before and it was always a mess!

Ohh, why, it's not work like this. Just use black electric tape and stick battery to wires.

bjwil1991 wrote on 2025-03-03, 04:59:

Got a PMD-5500 Pentium-90 laptop with a TFT display and CS4123 sound chip with an OPL3 FM synthesizer on it. It boots to strictly DOS command and I was able to copy game files over to the 810MB IBM hard drive. The downside is the stretched display with DOS games and I couldn't find anything in the BIOS to disable that.

If anyone can modify the BIOS for the laptop to have that feature, HMU. I'll get the BIOS from the chip onto a file.

It's chips & tech video according to this: https://www.macdat.net/laptops/dual/pentimedia_ii.php

You should try out this utility, it might work for you too!

Thermalwrong wrote on 2025-02-26, 03:04:

Nice find, what's the LCD model in it? 9.5" TFTs are generally quite rare now and a real pain to replace like for like. I found […]
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3lectr1c wrote on 2025-02-25, 20:41:

Took me long enough but I've found a WinBook XP! Better, unlike my XP5, this one actually starts up every time! […]
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Took me long enough but I've found a WinBook XP! Better, unlike my XP5, this one actually starts up every time!

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Specs:
- Desktop Socket 3 Intel i486DX4 @75MHz (overclocked to 100MHz 😁)
- 32MB of RAM!!!! Fully maxed out.
- 1.3GB Hitachi HDD
- Windows 95
- 9.5" Active Matrix LCD @640x480
- WD90C24 Video
- ESS AudioDrive 1688
- Lexmark keyboard (same switches as a ThinkPad 755C!)

It really is an excellent DOS gaming system - this one even lets you pick between 640x400 and 640x480 scaling via a keyboard shortcut, unlike my XP5. It has a decent on-board speaker and sound playback works great. The keyboard and input device options (you could get these with a trackpoint, trackball, or even a trackpad) makes them super configurable systems.

Problem of course is that they're unreliable, largely due to the soldered varta battery that I've mentioned before in this thread. This XP had nearly no leakage and no actual damage - I replaced the battery with a new one.
These will also completely fall apart around the hinges unless heavily reinforced with JB Weld. I've done that to this unit and hinges are now a-ok. The downside is that you do have to loosen the nuts on the hinges to make them very loose or the plastic will still break, even with reinforcement. This is fine if you're using it at a desk (they're still tight enough to hold the screen up), but if you're using it on your lap then they will fall backwards very easily.

This laptop has one functionality issue - the LCD panel is suffering from what I call "subpixel disease" where subpixels around the corners and edges of the screen malfunction. It's the same issue that affects mid-late 90s IBM displays, although this laptop uses an uncommon Hitachi panel.

I have noted that the CPU cooling design in this laptop is extremely flawed. The CPU is located under a removable cover on the bottom of the laptop. The cover is made of metal, but it doesn't actually contact the CPU at all. When I applied paste to the CPU, it wasn't spread whatsoever when I reinstalled and then uninstalled this cover. I was going to leave it be, after all, the engineers deemed it ok, but then I checked to see if it would overclock to 100MHz.... and it did, and was rock solid stable. So I had to get rid of this bluetooth heatsink.

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I ripped a copper contact plate off of a spare laptop heatsink I had lying around (it was from a Dell Latitude E6420). I then sanded off the thermal glue that was used to adhere it to the heatpipes, and then once it was flat, I sandwiched it between the CPU and that metal cover with thermal paste on both sides. This seems to have done the trick perfectly, as the paste spread and the metal cover now gets quite warm when the system is running. Overclock is still stable and it hasn't crashed a single time - nice! Saved myself having to pay out for a legit DX4-100 chip.

Eventually I will rebuild the battery to get this laptop portable again, and hopefully source a replacement LCD panel. It's definitely a great option!

Finally, a photo of my XP and XP5 together. I think I've changed my mind on which is the "ultimate" option for me - the 486 is still cooler in my opinion, but the extra Pentium performance of the XP5 is a big plus, and the screen is larger (and higher quality), and it has stereo speakers.... If only mine didn't have serious power issues that make it completely impractical to actually use.

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Nice find, what's the LCD model in it? 9.5" TFTs are generally quite rare now and a real pain to replace like for like. I found an NEC NL6448AC30-12 that 9.5" VGA TFT but it requires adapting the pinout and thats if it even fits. My trouble with fixing the T2150CDT / 400CDT / T4900CT laptops is that the LTM10C021 LCD has a really tiny bottom bezel area because of the LCD design so almost nothing fits that space other than the LTM10C021, which isn't cheap.
I think your findings match up to mine pretty much, I like the T2150CDT but being a 486DX4 with no L2 cache, it's not as quick as even a 400CDT. Great for adventure games but not as fast as I'd like with some FPS games.
Good cooling upgrade too, it seems like very few manufacturers really considered the thermals of the 486DX4, possibly because it was a 3.3v chip, but they still really benefit from better cooling.

Thermalwrong wrote on 2025-02-21, 03:31:

Hmm, I had no idea that was so well specced. Shame about the neomagic video but it looks really good otherwise. […]
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MAZter wrote on 2025-02-19, 01:58:

[…]
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Hmm, I had no idea that was so well specced. Shame about the neomagic video but it looks really good otherwise.

------------
Going back to the vertical stretch on chips & tech video equipped laptops, have you ever seen these black bars on the sides and this awkward fullscreen vertical stretching in games with some laptops?

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Now I know why this happens... The Chips & Tech CT65545 / 65548 supports vertical stretch of both text and graphics mode, but only supports horizontal stretch of text mode, not graphics! With a 640x480 display that's just fine, it can line double horizontal 320x200 stuff for full screen on a 640x480 lcd. However on an 800x600 LCD panel it can't evenly double 320 into 800 so it seems it just doesn't stretch graphics mode horizontally. Reading the datasheet for the 65548, there's specifically no mention of horizontal compensation for graphics mode, only text.

If the laptop vendor enabled vertical stretch and horizontal stretch with an 800*600 screen then that's fine in text mode, but graphics can only stretch vertically not horizontally so we end up with the odd stretched games. They did everything they could but the C&T 65545 / 65548 just can't properly stretch a 320*200 screen to an 800*600 LCD panel:

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Well as you can see, it can't eliminate the black borders but now the aspect ratio is better 😀

Just requires tweaking register 3D7h - 5Ah from '01' (Olivetti Echos PxxxE & Zenith Data Systems Z-Note GT) or '00' (Satellite Pro 410CDT) to '04'. And make sure 3D7h - 57h is set to '23' to enable v-compensation in graphics mode.

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Now I've seen this work on multiple laptops, I *really* need to figure out how to make a program to do this, such a small change makes such a good difference.

Sadly this does confirm for me that laptops with the CT65548 and an 800*600 screen can't do fullscreen 320*200 without black borders, but at least the aspect ratios are correct now. This means that the later chips like the HiQV (65550) are a requirement for fullscreen 320*200 on SVGA LCD panels.
I wonder what it'd take to swap a 640*480 LCD onto one of these? Should just be some register twiddling like the PC110 mods to switch from DSTN to TFT mode, just switching from SVGA to VGA TFT mode...

Okay so, wondering if I should perhaps make a thread for this because there needs to be an 'all-in-one-place' thread for laptop LCD scaling. This was resolved rather trivially using a utility I found I had that's been shared on driverguide for a long time: https://www.driverguide.com/driver/detail.php … riverid=1265806 and yyzkevin's site: https://www.yyzkevin.com/pc110/65535-2/
There's a utility for controlling these registers cleanly that was provided by Chips & Technologies for demo & testing purposes a long time ago called 54XSET.EXE. With it you can do funny stuff like green screen or inverting the screen, but running "54XSET.EXE OE" modifies the registers for horizontal and vertical compensation so that 320x200 is stretched to fully fit a 640x480 LCD, or give correct 4:3 scaling with black borders on an 800x600 LCD. Just add that into the autoexec.bat and it'll take effect as soon as it's run until the computer's restarted, then the scaling looks like the pictures in my last post about this.

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This and the WD90C24's stretch utility, both seem to be otherwise unknown. This 54XSET utility does seem to be the best way to fix scaling on C&T CT65535 -> CT65548 graphics chips.
(so much better than me trying to make an assembly program to do the equivalent and it's more controllable)

This utility should work on your laptop and give proper 4:3 scaling 😀

bjwil1991 wrote on 2025-03-03, 04:59:

Got a PMD-5500 Pentium-90 laptop with a TFT display and CS4123 sound chip with an OPL3 FM synthesizer on it. It boots to strictly DOS command and I was able to copy game files over to the 810MB IBM hard drive. The downside is the stretched display with DOS games and I couldn't find anything in the BIOS to disable that.

If anyone can modify the BIOS for the laptop to have that feature, HMU. I'll get the BIOS from the chip onto a file.

Oh sweet, you found the Pentium version of the PMD-5500 (aka PentiMedia II)! Thermalwrong already linked the page I have on my website on this laptop - it was made by Dual Technology Corporation.
I could really use the full specsheet for that one! I'm assuming most of it aside from the processor is the same as the 486 version, but I'd like to confirm. I could also really use photos of it (one of each side) that I could put up on the website.

It's unfortunate that the PentiMedia II uses the CS4231 sound chip - it would be a quite nice DOS gaming machine otherwise.

Edit: wait, you're saying it has an OPL chip on-board? If true, I wasn't aware that the CS4231 even supported that.

Edit two: The LCD should be 640x480 - I'd be very surprised if it had an 800x600 panel installed. Could be wrong though.
CPU switch settings for that model are also posted on my website, you can upgrade it to a Pentium 133. They should use standard desktop CPUs.

These are the specs that I currently have for the Pentium PMD-5500 (based off print ads I've found). At least in the case of MPC Technologies (who sold these), those were the three display options they had. No TFT 800x600 panel.

It does appear that it has Sound Blaster support, it was advertised as such. Neat!
You can see what specs I'm missing in the image - filling in any blanks would be a big help!

3lectr1c wrote on 2025-03-03, 16:56:

Oh sweet, you found the Pentium version of the PMD-5500 (aka PentiMedia II)! Thermalwrong already linked the page I have on my w […]
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bjwil1991 wrote on 2025-03-03, 04:59:

Got a PMD-5500 Pentium-90 laptop with a TFT display and CS4123 sound chip with an OPL3 FM synthesizer on it. It boots to strictly DOS command and I was able to copy game files over to the 810MB IBM hard drive. The downside is the stretched display with DOS games and I couldn't find anything in the BIOS to disable that.

If anyone can modify the BIOS for the laptop to have that feature, HMU. I'll get the BIOS from the chip onto a file.

Oh sweet, you found the Pentium version of the PMD-5500 (aka PentiMedia II)! Thermalwrong already linked the page I have on my website on this laptop - it was made by Dual Technology Corporation.
I could really use the full specsheet for that one! I'm assuming most of it aside from the processor is the same as the 486 version, but I'd like to confirm. I could also really use photos of it (one of each side) that I could put up on the website.

It's unfortunate that the PentiMedia II uses the CS4231 sound chip - it would be a quite nice DOS gaming machine otherwise.

Edit: wait, you're saying it has an OPL chip on-board? If true, I wasn't aware that the CS4231 even supported that.

Edit two: The LCD should be 640x480 - I'd be very surprised if it had an 800x600 panel installed. Could be wrong though.
CPU switch settings for that model are also posted on my website, you can upgrade it to a Pentium 133. They should use standard desktop CPUs.

I think there might be a few variations of the PMD-5500, just remembered I bought one ages ago and it's now sitting in storage. Mine is a 486 with a Gallant SC-6000 clone soundcard apparently??
You can see the pics here: Re: Bought these (retro) hardware today

bjwil1991: was this one from galesburg illinois or somewhere else? One sold for auction pretty recently and I was watching it. That's a nice TFT in the auction pics.

Oh also you've got to try out its party trick, the LCD is removable and flippable 😁

There are two versions of the PMD-5500 - one that used Socket 3 486 processors and the other which used Socket 5 Pentium chips. Dual released several laptops in that same/similar shell and the PMD-5500 (officially called the PentiMedia II) is the second of them. Both versions would have been released around the same time, with the 486s being the lower end system. The rest of the specs are supposed to be the same between the two. Neat idea that I haven't seen any other laptop manufacturers do. You have the 486 version of the laptop.

Your post is how I was able to document the specs of the 486 version actually! There is an image of the sound card on the webpage you had linked in your earlier post.
http://www.szetszedtem.hu/149laptop486/1600/6 … -76/071hang.jpg
You can see it's using the CS4231 chip, and yep, there's a Yamaha IC right nearby.
The board in that photo is labelled as "PMD-5000", which is the model number for the PentiMedia 1, which released in 1994 and was the first to use this case design. I'd assume based on that that the PMD-5000 uses the same card (it definitely did have *a* sound card). Unfortunately no one has documented those online yet so I don't have much info on them beyond them having a 486 and Pentium version just like the PentiMedia II.

Just took another look through the PMD-5500 BIOS release notes and the second to last version of the Pentium BIOS (released 1996/04/13) added support for an 800x600 TFT panel, so it did exist.

Is there a utility for making the display not get stretched while playing DOS games?

It was linked in the post from Thermalwrong above. Your laptop has the C&T 65545 video chip so it should work, in theory.

Yeah, I just opened the whole quoted thread. I put it on a diskette and tested it on two Pentium laptops: DGi FMA7600 and the PMD-5500. I typed in 54XSET OD and launched a game. No longer stretched, so I added the command to autoexec.bat to see how it performs. Going to see if Windows 9X would shrink or stay in the 640x480 resolution.

So, does your PMD-5500 have an 800x600 panel then? If so, you’ve got a late production and high spec unit! That’s one nice and super modular laptop. I’d love to get my hands on one of those someday.

Should also work fine as you’ve seen with your FMA7600, which is the Nan Tan 7600 - it also uses the 65545 video chip.

Sadly, it's 640x480 for the display. Ironically, I can set the resolution to 800x600 and move the mouse around to go around the screen. For the price I paid for this laptop, I can't complain. Except for the brittle plastic. But other than that, with a GamePort, I can hook up my MIDI boxes to it and a joystick.

With the command set in the autoexec.bat, DOS isn't stretched and Windows 9x boots happily with the native resolution of 640x480 without issues. The one FMA7600 laptop I have has issues with PCMCIA cards being installed and would lock up the system. I have some Pentium 100 CPUs somewhere so I can adjust the speed and make it reliable. Not sure if it's because of the clock speed or something else causing it to not work. And the sound card does have the YMF-262M chip on there for Adlib support and it has Sound Blaster support as well, but I'm not sure how accurate it is yet.