The Siemens Nixdorf PCD-4ND is a rather common piece of old laptop, and actually it is a very decent one! In short it is a very nice piece of equipment for daily use with a not too fast but still decent color LCD display driven by the good old Cirrus VGA chip (512Kb VRAM), a 4.86 processor at 50-100 MHz, and native Sound Blaster compatible sound solution in certain models. These features can make it ideal for running most of the games and software from the old DOS era.


PCD-4ND Image
PCD-4ND Image
PCD-4ND showing a pixelart

This old brick of notebook not only shines in it's features for offering just the right set of hardware for running most of the old DOS software, but also in that it is probably the easiest to maintain, much better than any laptop from either in the past or the recent times. Just unscrew some screws, and you got it in pieces without breaking anything. It also seems considerably durable, most particularly at the supports of the LCD panel: these won't just wear and break like for example IBM models' hinges. To mention something on the dark side it has to be noted though that you could literally bake coffee on this thing, so without some modifications it is probably not a good thing to run it in full speed mode for long. But all in all this is still a notable piece which one should probably acquire if he wants to experience some of the past in real.


  • CPU: Intel 4.86 DX2 at 50MHz or DX4 100MHz (Depending on model, in Turbo)
  • Floating point unit is integrated in the main CPU
  • RAM: 4Mb on board, expandable with proprietary RAM module (16Mb, usually included)
  • VGA: Cirrus Logic, 512Kb VRAM (SVGA, 256 color 640x480 mode supported)
  • HDD: 500Mb included, standard 2,5" IDE HDD
  • FDD: 1.44Mb removable unit (Citizen)
  • LCD: 640x480 color DSTN
  • Keyboard: German layout, emulated numeric pad
  • Mouse: Integrated trackball (Recognized as PS/2 mouse), serial port available
  • Sound: ESS AudioDrive + Yamaha OPL3 in some models (Others: PC Speaker)
  • Connectors: VGA, 1x LPT, 1x Serial, 2x PS/2 (Kb, mouse), optional audio connectors, dock
  • Power: 230V AC, Power supply: 22.8V DC, 1.3A, middle positive
  • Battery: 14.4V 12 cell NIMH, 1800MAH, two can be attached
  • Weight: Goddamn big brick. The LCD panel and the battery adds the most
  • Year: 1995
  • Others: Microphone included in ESS sound chip equipped models (Near the trackball)

The LCD panel is of decent quality, it gives good colors. The backlight however may be more or less uneven, one of my laptops seems to be subjected to some abuse before which made this somewhat worse, in some contrast / lighting settings it may be annoying even with one which was well cared for. Dim vertical stripes can only be visible rarely with special images.

Firmware features

PCD-4ND Keen
PCD-4ND Keen
PCD-4ND running Commander Keen 4

Interestingly contrary to the Chicony NB5620 the FN key features are more sparse even though the Cirrus VGA chip would support all what the older laptop's one did. The most notable miss is the ability to control the picture over the LCD which may otherwise help to acceptably display ModeX dependent games (Like Albion with it's 360x240 mode) and software (Like AdLib Tracker II). An other feature I missed is volume controls for the speaker. Otherwise here the FN functions are properly labeled, and the most important controls are there like the low power mode (Turbo) switch or the brightness and contrast adjustments of the LCD. It's interesting that this laptop can do these while color IBM laptops couldn't.

The BIOS itself is not too rich at features, and it's layout is a little strange having the boot media setting in the security menu. At least it is easy to reach it for that the entry key appears both on the keyboard and during boot on the display. Some self-diagnostics, HDD auto-detection, and a low level format option is probably what I would miss the most.

Sound support

PCD-4ND Chips
PCD-4ND Chips
The ESS AudioDrive and the Cirrus VGA

Some models of this laptop have a good Sound Blaster compatible sound support materializing in an ESS AudioDrive sound chip accompanied with a Yamaha OPL3 FM chip. The best part is that to work these don't require any drivers, and a lot of games and software also supports this particular hardware (As ESS Technology ES688) not even needing to set it up as just Sound Blaster compatible (But of course that works too). Note that for that it includes a real OPL3 chip, it will need the AdLib delays when accessing (This is important for example with AdLib Tracker II which would skip these delays by default). The hardware also includes a microphone situated next to the trackball.


The graphic is ran by the good old Cirrus VGA which provides very good access times to guarantee that the games and other graphics-intensive software won't wait for it to work. Note that though that apparently it has some problems with the framebuffer, some SVGA games may require some related setup before they would work. VGA games (So most of the old games) of course will go without problems. ModeX games and software will fail to display properly on the LCD if they show more than 640 pixels in 16 color mode (AdLib Tracker II for example), or 320 pixels in 256 color mode (Albion for example). If possible, set these up so they won't try to use more pixels than possible. Some time in the future I might program a fix for it (Cirrus VGA can cram 720 pixels in a 640 pixels wide LCD with some programming), so these software will show somewhat acceptably.


First, to save you the trouble, this laptop unlike some others from the time, has all the important peripherals at easily accessible places, so you may not even need to actually disassemble it to replace something. So at first I will outline these common tasks.

The hard drive

The HDD is situated between the battery and the floppy units, accessible from the backside. The compartment is held in place by just two screws situated on the front just above the clips holding the battery and the floppy in their sockets. After removing these a little force may be necessary to lift the compartment (do it with a flat screwdriver if it doesn't want to go), and you can flip it like on the picture. The HDD itself may be covered with some shielding or not (If it has the shielding then that was which made the compartment harder to remove), and might be held in place by additional screws. After removing those, you can pull the cover off of it. To remove the IDE connector, use a flat screwdriver and carefully work it off by loosening on the edges. You can replace it to any ordinary IDE 2,5" HDD.

RAM expansion

It is unlikely you will want to replace this as it is a proprietary module, but if you need to remove the mainboard, you will need to do this as well. The cover for it is on the backside, above the battery, held in place by two screws. After removing that, you may either see something like on the picture, or somewhat less. I don't mean the absence of the RAM module here, but that older models had just a thin cover only revealing the edge of the module. The RAM itself holds on to it's socket very hard, it is painfully hard to remove it if you happen to have the older model (Use the above mentioned flat screwdriver and move it side by side while pulling to carefully loosen the module). With the 16Mb RAM module, the laptop has 640Kb base plus 19Mb extended memory, without it, it has 640Kb base plus 3Mb extended.

LCD display

PCD-4ND Opening
You only need to remove 3 screws to replace the LCD display unit. These screws are situated on the backside, in the upper part, under where the other side the LCD attaches to the laptop. After removing these screws, flip the laptop, open the LCD, and gently pull it upwards. It will come loose, nothing (Yes, nothing, no wires at all!) holds it in place. The LCD is connected to the rest of the unit through a connector located in the middle of it's base, well, it is a very nice idea, but sometimes it may be the source of a problem. This connector for the regular opening and closing of the laptop seems to oxidize faster than other connectors. If the LCD seems unstable which seems to fix after bending the display a little, then that's the problem. Some contact spray will help this.


The processor unit is accessible from the top after removing the labeling strip of the F keys. When that strip is removed, a screw might reveal, unscrew it, then with a clip, you can remove the cover what will reveal the main CPU (Either a 4.86 DX2 or a DX4 probably with some kind of heatsink applied. The problem with this socket is that without special tools you can't remove that little board the CPU is installed on, so if you are really in this business (Like for creating some better heatsink for this thing), you will need to actually disassemble the laptop.

The actual disassembling

PCD-4ND Backside
First you should start with removing the LCD unit as the screws holding it in place also hold the two halves of the main case together. After it is put aside, you can continue with unscrewing all the screws on the bottom (Except for the HDD enclosure: You won't need to remove the HDD unless you want to remove the mainboard from the case). Note that there are two screws, one under each, the battery, and the floppy drive too, so remove these as well. Then on the backside there are six screws among the connectors: You don't need to remove all of them, only the ones holding the upper side of the laptop (unless you are going to remove the mainboard from the bottom). After these all removed, you can open the case. This can be started from the battery side as there is a lone clip on the floppy unit side which will come loose on it's own this way.

PCD-4ND Kb. cord
To remove the top cover with the keyboard, you need to disconnect either one or two things depending on the model. One is the keyboard which is held in place by a clip connector: use a flat screwdriver on the connector's edges to raise it, so the keyboard cable comes loose (When assembling, after fitting it back, you need to push this to fix it in place). If your model has sound, you will find two wires going to the speaker as well, but that has a simple connector, so it's not of any problem. With this you are basically done, from here there shouldn't be any problem further on if you need to do anything else. Just to mention, if you want to remove the mainboard, remove the hard drive and the memory expansion card first. Then after unscrewing the screws at the connectors, with a little care, you can just pull it off from the bottom (Among removing the tape holding the trackball's wires in place).

One thing to fix this time may be the speaker: For me those thin wires were worn, they didn't make proper contact with the cone which made the sound unstable at times. It just needed removal and re-soldering.

Problems with overheating

The laptop's designers seem to have gone a bit too far with allowed heat buildup, so that in the 100MHz model in turbo mode you could literally cook your morning omelette. The processor unit's heatsink gets too hot to touch. To let the thing live longer you should probably not run it in turbo mode at all (You can do this in the BIOS, at power management). You can of course turn on or off turbo mode any time by the appropriate FN key combination.

For me it seems like it is possible to fix it with proper heat conducting, I might do it some day to let it running better. At least that will be a nice thing in the winter. :)

Notes (2013.04.23)

As of now I discovered the cause of the malfunction of sound: it is caused by a short on the heavily patched audio-video board, as of now it sadly seems to be unfixable (From times to times I try to work on it, but until now, with no luck).

However if you have a PCD-4ND which you wish to sell, especially if in Hungary, feel free to contact me. I think this little laptop really worths more attention and preservation, so I might well end up collecting it, hoping to maintain proper part supply to maintain the ones in better shape.

Referred artworks

  • PCD-4ND Image
  • PCD-4ND Keen
  • PCD-4ND Chips
  • PCD-4ND Opening
  • PCD-4ND Backside
  • PCD-4ND Kb. cord



  • Created: 9 Dec 2016, 8:10pm

Hi Sakhile! With these old machines it might happen that the HDD is more or less broken, although it is possible it only lost data collecting dust in an attic for decades. Formatting them, installing a fresh system (a variant of DOS possibly) could help. Otherwise you might need to change the HDD which isn't a problem for these (they accept normal laptop IDE HDDs, you might even use a CF card with a CF-Laptop IDE converter).


  • Created: 12 Nov 2016, 10:59am

when I switch on laptop Siemens nixdorf laptop it says invalid system disk


  • Created: 8 May 2016, 9:05pm

I don't really understand the situation. This computer's power plug is a fairly standard round plug, found on just about any universal power supply, and it is even the more common middle positive. Before frying the poor thing, you should try to apply power there, if it works, it should come alive from even as low as 14 Volts. I sold my PCD-4NDs to a collector a while ago due to having no room and time for them, however I still have a PCD-5ND which is identical for the power & battery details. The old battery certainly can be at fault, but the laptop can power up without battery all fine. If it doesn't, it likely has some other problem.


  • Created: 7 May 2016, 3:42pm

Does anyone have any circuitry info on the PCD-4NCsx/25, in particular the wiring from the power input connector to the battery contact springs? I have one of these laptops which does not power up and know that the battery is at fault but, although the power unit is definitely OK, I can't charge the battery. Alternatively, I'd like to power the PC direct from an external 20v DC source but, ry as I may with checks at the battery contact springs, I can't power it up.

Any help or advice will be appreciated.

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