Osborne 1 - Resurrection

[Brunhold]

Hello to all casemodders out there!

After my last project, the BRUBCAT, I have decided to start a different casemod. I bought an empty case of a busted Osborne 1 from 1983. "Different" casemod, because I wanted to keep the original look, which means no holes for fans and no lights, but inside modern hardware.

The comparison:

1981:
year of constr.: 1983 (release of first model 1981)
quantities: about 125.000 (1982)
processor: Zilog Z80A, 8-bit
frequency: 4 MHz
RAM: 64 KByte
ROM: 4 KByte
OS: CP/M 2.2
monitor: 5"-Monochrome (black/green)
textmode: 52 x 24; 80 x 25; 128 x 24
keyboard: QWERTZ, number pad, 69 keys
drives: 2 x 5,25" for 102 KByte-disks
interfaces: 1 x IEEE-488, 1 x RS232C, 1 x Centronics, 1 x Modem, 1 x Video, 1 x Battery/Accu-adapter
size/weight: 51(W) x 32,5(D) x 22,5(H) cm / 10,2 Kg

2006:
processor: AMD Sempron 2600+, 32-bit
frequency: 1833 MHz
RAM: 512 MByte
HDD: 160 GB, Samsung
OS: Microsoft Windows XP Professional
monitor: 5"-TFT
resolution: 320 x 234 pixel
grafix: MSI Geforce Ti4200, 8xAGP, 64 MB RAM
keyboard: QWERTZ, number pad, 104 keys
optical drive: DVD-ROM, Pioneer DVD 104s, slot-in, 5,25"
interfaces: 3 x USB, 1 x S-Video, 1 x VGA-Out, 1 x Audio-Out und 1 x Mic-In, 1 x 10/100 Mbit-network
size/weight: 51(W) x 32,5(D) x 22,5(H) cm / 11,5 Kg

The story has its ups and downs, sometimes I have been close to to defenestrate the case, but I finished the mod finally after 6 months.
If my english is incomprehensible, please let me know.

Step 1: The cleaning
I had no chance against over 20 years of smoke and sun, the case has been yellowed on some areas. But the result is alright though.

Step 2: The keyboard-mod
The osborne keyboard has 69 keys, the new one 104, that means work.

I did not like the red color of the mouse.

First problem: The controller needs more space than available.

Now everything fits.

The original backplate, which held the old keyboard can be used to hold the new one, too.

Detail:

Step 3: Teevee
The old 5 inch CRT has been replaced by a TFT.

CRTs have a curved front, TFTs are flat, that is why the frame of the Osborne-front has to be modified.

I did not want do dismantle the TFT. It is hard to find a LCD like that and I have bad memories, because I have killed a LCD long time ago.

Test

[Brunhold]

Come on! Let us proceed, there is still a lot of work to do, and a lot of pictures left!

Step 4: The underground
The Osborne 1 has two floors, and I have put the power supply unit and the hard drive in the lower one .

Step 5: The upper level
A small mainboard is found, because space is narrow.

The fan, which blows the air out:

This is close-fitting:

Step 6: Modding the front
The front-fan needs a grill, silver inside, black painted outside.

The DVD-cover is made of black cardboard. Sorry, but I have not had something better at that time. It was very important to build in a slot-in drive, because the 5 inch disk drives of the 80ies have not had a drawer like optical drives nowadays.

The DVD-drive-busy-LED needs a new position:

On/off switch...:

...and the connector to the mainboard.

[Brunhold]

Step 7: Modding the front interfaces
The front is removable and it would be perfect to mount the interfaces on a batten (right expression?), which is fixed inside. But because of space problems, the batten is screwed on the front.

Elongation of VGA-cable...

...and audio. Almost every connection from the mainboard is repositioned to the front.

Features: 3 USB, 1 VGA-out, audio-out, mic-in, TV-out

Step 8: Assembly

Test before installing Windows:

Everything finished:

After three hours of program installations the PC ran silent and everything looked fine. I slept like a log in that night. The next day I started the osborne again, but ... what was that? Klickklack ... klickklack ... klickklack ... klickklack ...

[Brunhold]

Many thanks, I appreciate that!

But I have to go on with my story, which is long, very long. I hope you have the endurance to hang on.

Back to klickklack.
This is a 80 GB exhibit:

But why did it die?
The heat is bearing the blame! This is the result after measuring the tempertures: PSU - 60 degrees Celsius, the hard disk - 56 degrees, CPU - about 50 degrees. This is definitely to much!

Step 9: Improvement
After buying a new hard drive, I inserted a few more fans. Two 4cm-fans sucking hot air away from the hdd and one 6cm-fan blowing fresh air inside, nearby the PSU. I misused the two boxes in the front. Usually you can store your 5inch-disks there (it is still possible), but now they are air ducts.

Argh, the tests have not shown much better temperatures than before. This is one of those moments ...

Step 10: Improvement #2
I reversed the airflow direction and inserted more fans! Instead of two 4cm-fans blows one 8cm-fan, which is only 15mm thick, fresh air directly on to the hard drive. The remaining holes have been covered. On the other side are now two 6cm-fans, which suck worm air from the PSU to outside.

No air holdup anymore, this is the key fan:

The same reversion on the upper floor! Front fan blowing fresh air over graphics card, the grill has been modified and in the upper cap are two 6cm-fans blowing warm air outside.

Thinner CPU-fan leads to more space to the cap.

[Brunhold]

Step 10: Final test
Temperatures: PSU - 35 degrees, HDD - room temperature, CPU - about 44 degrees. Perfect! Ready for continuous duty. Ok, the PC is explicit hearable, but it is cheaper not to buy a hard disk every week.

We have picture on 28"-TV and on the 5"-TFT:

Thank you very much for your attention!

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