My "new" 486 laptop

Greetings,
Just arrived home with this great computer from Freecycle.

It's specs are:
CPU: 486DX @33Mhz
RAM: 4Mb
HDD: 120Mb
FDD: 1.44Mb
GFX: Monochrome screen
I/O: 1x RS-232 serial port,1x PS2 for mouse,1x PS2 for keyboard,1x VGA Out,1x Printer
OS: It boots to MS-DOS 6.20. It has Windows 3.1 installed

But it has a few minor problems:
1- The "i" key is acting weird. When I press the "i" key, it moves the cursor to the beginning of the line. May be a problem with the keyboard connector?

2- I had to remove it's battery. If I turn the computer on with the battery inside, it shut's down after 10 seconds.

3- CHKDSK reveals some bad sectors on the Quantum 120Mb hard drive. I think it is a 2.5" IDE HD (haven't opened it yet). If so, I have a spare 20Gb HD. I can then create a couple of 2Gb partitions and I'm good to go.

It's keyboard is awesome, with a great tactile feedback on each keypress.
It's trackball mouse is also working well.

Tomorrow morning I will take it apart, give it a good cleaning and take a couple more pictures to share.

Cheers

Very nice! Love those monochrome LCDs, too. Hope you get the keyboard working well, those keyboards are great.

manicminer said:

2- I had to remove it's battery. If I turn the computer on with the battery inside, it shut's down after 10 seconds.

Click to expand...

A shorting problem?

CHKDSK reveals some bad sectors on the Quantum 120Mb hard drive. I think it is a 2.5" IDE HD (haven't opened it yet).

Click to expand...

Reformatting solves this problem, but I'd do it only if the bad sectors prevents the laptop from booting and being used properly.

It is common for very old batteries to short so the system shuts down. You can tape over the contacts so that the battery can be installed and allow the system to run.

Reformatting will keep known bad blocks from being used (as long as the bad blocks are not in the FAT table area). Problem is some drives will continue to form bad blocks making the drives unusable after a while (head crash might have kicked up some particles). You should be able to get another HD of the same size (anything under 540MB) to replace the old one.

What brand and model number is it?

If you have or can find a copy of SpinRite it will do the reformat in-place.

Thank you all for the replies.
Pictures updated in the first post.

>> NathanAllan: I took it's keyboard from the case, gave it a good cleaning, cleaned the contacts to the motherboard, but it was no good. The "i" key acts weir because it registers the key-press, and then puts cursor on the beginning of the line. It I Right SHIFT+i, it prints "i7" on the screen. If I press the Left Shift, it shows the last commands used. The DEL key displays the "»" symbol. Very weird... External PS/2 keyboard works great.

>>DOS lives on!!: It was shorting problem. I have tapped over the contacts and now it stays on.

>> Unknown_K: I tapped the contacts like you said. It works now. Thank you . I'm trying to avoid reformatting because it's previous user made a great work in the software side. It boots to a nice Menu, allowing me to choose EMS, XMS, Ramdisk, Windows. Maybe I'll clone the HD and put a "new" HD inside and then install MS-DOS 6.22

>> strollin: The label says: DUAL GROUP. It's model number is SDK-4000. I did not find any information on the web about the company.

Cheers

UPDATE: Keyboard still not working 100% after a good cleaning. Starting to scratch my head.
Also, tried to upgrade it's Ram. I had 2 x 16Mb single side modules in my Akai S2000 Sampler. The laptop won't boot. No image on screen. Tried with 8Mb double side Ram but also no picture on screen. With 4Mb single side it works alright. I don't have any 8Mb single side stick, but I guess it would work.

Cheers

What type of RAM? Couple be FPM or EDO (definatly not SDRAM) or just proprietary.

Is there any indication as to who made the laptop, other than Dual Group? Example is CompuAdd, they released laptops but they were made by Lexmark and Epson. I would start to think about getting a compatible keyboard to replace that one with.

Also, are there any part numbers on the ram?

>> NathanAllan: No, there isn't. THe only reference to the manufacturer is Dual Group. The RAM is a standard EDO ram. I tried today with a couple more. All the single sided ones worked alright. Double sided won't allow the computer to boot.

Today I worked on the keyboard. Opened it and cleaned all the contacts. It still acts weird. "i" registers "i7", "p" registers "4", DEL registers "»" and so on. With PS/2 external keyboard there's no problem at all.

Any hint?
Cheers

Try turning number lock off.

Thank you Unknow_k. Done that. Same problem.

I had a laptop identical to that, but branded different, I am pretty sure whoever actually built that, did so for other companies to rebrand.

Unfortunately I let that laptop go last time I moved, I wish I remembered how mine was branded, or that I had kept it so I would have spare parts to offer you.

FYI the CPU IS upgradable in that thing (at least was in mine), I had an AMD 5x86 133 booting in it (though if I recall not at 133mhz, I want to say it clocked to 100mhz IIRC because mine was a 486-25 to begin with, and I couldn't figure how to change CPU speed, and I figured underclocked was better for cooling).

I’m a little late to this conversation but I’ve just bought one of these mine is labelled ypsilom skd-4000.

id also potentially like to upgrade it to run a different cpu and ram so looking for information about the manual and what settings I’ll need to change the voltage / clock for a processor.

ive seen pictures of others running a dx2 50 so I was toying with a dx4 100 but reading the last comment from many years ago i may try for a 586 133 I love this old tech.

anyway if anyone still has one of these and wants to advise id be interested.

btw I found a website of another user that was on the listing of the one I bought. Though mine is untested so it may not even boot….

http://www.computernerdkev.heliohost.org/skd-4000/index.htm

Please start a new topic rather than post on this 10-year-old one.

- Alex