In these days i have had the necessity of a computer with the DOS operating system to create Boot Disk with the ImageDisk program, so i decided to retrieve my old Olidata P133 and install FreeDOS.

I have installed:

• 3COM 3C905 PCI Ethernet Card.
• TCP/IP Stack via 3COM 3C905 Packet Driver.
• Amstrad 1640 5 1/4 Floppy Drive (I had to change a jumper, see photos)
• Upgraded SIMM Ram (100 Mb)
• DOS Driver for Crystal 4232 Sound Card (SoundBlaster Compatible)
• A small fan for the cpu.
• Some Games and Utility.

Gallery:

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My Work Bench for small electronic Repair.

I am very happy to have repaired for my friend four PCB Commodore in one and half hour.

The defects are:

• Motherboard Commodore 64 ASSY 250466 with IEC bus broken. (replaced ic 7406 – U8)
• Motherboard Commodore 64 ASSY 250407 with a Video Output problem with some programs, like FIBR File Manager. (replaced ic 6526 – U2)
• Motherboard Commodore 64 ASSY 250425 with strange character at startup. (replaced ic 4264 – U12)
• Motherboard Commodore Floppy 1541 ASSY 1540050 REV C with IEC bus broken. (replaced ic 7406 – UB1 and ic 7414 – UA1)

My Modern PC with a 5.25 Floppy Drive (Epson SD-600).

This Floppy Drive model works perfectly with the programs: Omniflop / winImage / raWrite.

Download: Diskette Configuration Guide (1571)

I have recovered a Osborn 1 in pretty nice cosmetic conditions but broken ;-(

List of broken stuff:

• Startup Garbage screen.
• Long startup beep.
• Reset works 1 times out of 20.
• Modem port desoldered.
• Powersupply ripple.
• Some screws missing.

Solutions & Fixes:

• Powersupply Ripples: Replaced some capacitors.
• Modem Port de-soldered: Fixed the cold solder.
• Startup garbage screen/long beep/reset: I have replaced a broken 4116 RAM.
• Screws missing: Replaced with a new one.

I have to thank Terry ‘Tezza’ of Classic Computers Blog for the piggyback ram guide.

I used an oscilloscope to find the faulty ram cause all ram in my motherboard seemed to work well. In the photo #9 you can see the signal of the pin 2 (data in) of a faulty ram, while in the photo #8 the same signal of a working a ram.

I continue to upgrade my Amiga 2000 PAL REV 4.5. After the upgrade of the chip Fat Agnus and the Kickstart/4MB, today i have replaced the Denise chip with a new one. The Super Denise chip is capable of still higher resolutions and bit depths.

I have created a funny Poster with some things from my Museum.

Download: NightfallCrew Poster (29Mb / 4677 x 3307)

I had to make this change to get the Expansion Ram 320XL running on my Atari 800XL:

• 5v Power wire on PBI connector.
• Stabilize the clock signal for PBI Devices. (link #1 – link #2)

source: atariage.com

These are some Sid examples which i have recorded from a Commodore 64 with the SwinSID installed. You can Download the original Sid track in .sid file format and the SwinSID in .ogg file format (High Quality), so you can compare the musics.

• Natural Wonders 2 by Alexander Rotzsch (Fanta) 2008 Oxyron – SID (8580)
  
• Natural Wonders 2 by Alexander Rotzsch (Fanta) 2008 Oxyron – SWINSID

• The Alibi by Thomas E. Petersen (Laxity) 1989 Maniacs of Noise- SID (6581)
• The Alibi by Thomas E. Petersen (Laxity) 1989 Maniacs of Noise- SWINSID
  

• My Little Pony by Alexander Rotzch (Fanta) 2005 Chorus – SID (8580)
• My Little Pony by Alexander Rotzch (Fanta) 2005 Chorus – SWINSID

• Albino Human by Alexander Rotzsch (Fanta) 2006 Fanta – SID (8580)
• Albino Human by Alexander Rotzsch (Fanta) 2006 Fanta – SWINSID

Some Sid tracks play perfectly others need some emulation fixes.

I wanted to try my new desoldering station Aoyue 474A+ with the motherboard of the Commodore 64, i have unsoldered all chip and i have added a socket. It works so good and is so fast.

I continue to upgrade my Amiga 2000 PAL REV 4.5. I have upgraded the Kick Rom and added my Vector A2000i zorro Card with 4MB of fast memory.

I have decided to upgrade my Amiga 2000 PAL REV 4.5 for get 1MB of chip ram. I also took advantage of this update to install a new battery for the system clock. Amiga 2000 PAL REV 4.5 Fat Agnus 8372A Installation:

• Install a new Fat Agnus 8372A or 8375 (8375 R1)
• Look for jumper J101 beside the power connector to the motherboard. Change it to the opposite position. (photo)
• Look for trace J500 at the back of the machine near the Cia’s (8520′s). It’s a jumper trace that you will have to cut with a razor blade. (photo)
• Look for trace J102 near the Fat Agnus (8372A). It’s a jumper trace that you will have to cut with a razor blade. (photo)

source: amiga-hardware.com amigahardware.mariomisic.de amiga.org

My SIO2SD interface is dead (without any valid reason) after 2-3 hours of playing demos/games.

I have tried to reprogramming the firmware with a STK500 USB ISP Programmer and the tools AVRDUDE and it has worked perfectly.

The functions keys (Start / Option / Select / Reset..) of my Atari 130 XE not making good contact, i have fixed this problem with a good clean-up and graphite of a pencil.

This is a Joystick Adapter for Apple IIc, with this adapter you can use the Apple ][ Plus Joystick.

Joystick Adapter Pinouts: