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 (1488)

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.

Retro Innovations ROM-el:

To program the ROM-el chip by Retro Innovations you need a Adapter. The ROM-el chip uses a Atmel flashrom AT49F001AN (128K x 8) and we must build an adapter that converts the pins of the 2364 PROM Commodore 64 Kernel, which is used in ROM-el chip, to the original state of the chip AT49F001.

After this work, you can use the Willem programmer to program the FlashROM with one or more C64 kernel.

Nano SwinSID Prototype by x1541:

This project is based on the microcontroller ATMEGA88PU from Atmel and the emulation code is written by Swinkels.

The prototype of Nano SwindSID is a scaled down version of the Micro SwinSID, so far so good, and here’s my initial impression.

x1541, a user of the forum64.de has made a very nice work, the pcb has the same size of the original SID chip (6581/8580), the components are arranged very well and the entire space of the pcb was used. I can just say to buy it when the Nano SwinSID kit will be available, your money will be spent well.

Nano SwinSID Features:

• ISP Connector.
• Same size as the original SID.
• 6581/8580 Jumper.
• Smd ATmega.

source: forum64.de

This is a very old project published in a Dutch magazine to capture the state of the IRQ for Commodore 64 (vic-20) with a LED. After many years i have decided to make it.

On the photo you can see the project and the right connections on the cartridge port.

Components:

• 1 x IC 74LS04.
• 1 x Bicolor LED.
• 2 x 330 ohm resistors.
• Tiny wires.

How it work?

When the CPU generates an IRQ the green LED lights up, otherwise is red, if the irq is turned on and off quickly the led is orange.

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)

Finally i had time to finish the enhancements of my Commodore 64, below a brief description of what you see in the photos.

Enhancements description:

• 1541-III bulk version.
• Reset Switch.
• Multi Kernel with Atmel flash rom.
• Multi Kernel Switch.
• Eprom homebrew PLA.
• Cartridge ON/OFF Switch.
• DualSID with separate output (6581 / 8580)
• 2 x Fan Cooling.
• Fan Cooling Switch.
• Bright Blu Power LED.
• 1541 Ultimate REV1 with v2.0 Firmware.

DualSID KIT by Tomi Malinen:

DualSID is a device which allows you to plug in two different SID models to your Commodore 64.

You can set the second SID‘s address to five different memory locations. For more information and price visit the Tomi Malinen homepage

Download: DualSID V3 PCB Scan (631)

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.

Micro SwinSID KIT by Peter Sieg:

Certainly you can’t expect perfect emulation, but we are very close, the audio is much more clean than the original SID chip, if the project continues on this road we will arrive very soon on the perfect emulation.

Micro SwinSID (SwinSID88) is a hardware replacement for legendary SID sound chip which was placed in every Commodore C64 computer.

This project is based on the microcontroller ATMEGA88PU from Atmel and the emulation code is written by Swinkels. The first version of the pcb (prototype) was made by Crisp.

For more information and price visit the forum64.de.

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.