This particular diagnostics cartridge does not require a test harness, and are specifically useful when your C64/128 has no picture. What sets this cartridge apart from the other test cartridges, are that they all require the RAM to be functioning to boot, (unfortunately, one of the most common fault is defective RAM) This cartridge not only work with defective RAM, but it also can tell you which RAM is broken. The reason why this is possible, is that a correctly made DEAD TEST CART will not require the system RAM, but it will instead temporarily overwrite the kernal ROM bypassing a lot of functions needed to boot the computer. A random person can obviously just program his all purpose C64 cartridge PCB with the ROM file from the DEAD TEST Cart, but it will be useless when you really need it. Thats why I made this PCB specially for this one purpose, and did not just throw a ROM into a all purpose PCB.
Some people just want a SD card solution for their Commodore 64/128/VIC20 the cheapest way possible. So I came up with the “Pennnysaver Edition”. It has the bare minimum you would need to load your games and programs from a SD card, but with the possibillity for upgrades later. It can be used with your Commodore 64 or 128, VIC20, C16 or even the Plus/4. It will run on Raspberry Pi 1, Zero, Pi2 and Pi3. If you want to overclock those older Pi models, Use the config.txt to set the values. The sign # is used to make the Pi ignore the text. Remove it to enable the settings.
Note: currently the Pi’s HDMI screen is not suppported on the Pi Zero, 1 or 2. Note: currently the USB keyboard and drives are not suppported on the Pi Zero, 1 or 2. Note: currently the emulated drive sounds are not suppported on the Pi Zero, 1 or 2. These will be supported later, and the hardware is already set up for it when it is supported.
The simplest working Pennysaver PCB only needs 3 parts to work..
This is the version Im listing on Ebay for my cheapest option. It has most of the important stuff, and the rest can easily be added by the customer if they want.
So what is this Pi1541? The Pi1541 is a real time, cycle exact 1541 emulator by Steve White. It basically connects to a Raspberry Pi 1, Zero, 2 or 3 to emulate a Commodore 1541 floppy drive. Why do we need this when there is the SD2IEC? Its because a lot of games and demos utilize the chips inside the 1541 floppy drive, so without them, the program or game will not work. Here, the Pi is emulating those chips, so that the games will work. No more games that wont load due to incompatibility. The Pi1541 has room for all the buttons, LEDs, connectors and stuff that ports the Pi to your old computer, includind OLED screen. It can be used with your Commodore 64 or 128, VIC20, C16 or even the Plus/4. All you have to do is to copy the files over to the root of the Pi memory card, and copy your games and program into the same SD-card and insert it into the Raspberry Pi. You should check out the authors website for the latest version of the software. Link is below.
There are several ways to use this, but I decided to use it the same way I used to use the SD2IEC. I just start the File Browser and use the C64 keyboard to select my game. When everything is connected and turned on, I just use it as if it was a normal 1541 floppy. The latest news it that now, it also can emulate the Commodore 1581 floppy drive, it supports more file versions and it now also supports USB thumbdrives too!
Pros: – You will never face the potential compatibillity problems assosiated with the much discussed 7406 chip, since its not needed. – Its extremely cheap to make and easy to solder with a minimum of parts. – The PCB is ready for all the extras that I made for the full version, including reset switch, 5x menu switches, output for OLED screen, speaker that can be disabled with a jumper, power LED, activity LED, output so you can solder your own cable for the Commodore serial port, and it even fits my 3D printed case!!
Cons: – You will not be able to use other devices at the same time on the same serial port as the Pi1541 Pennysaver, since I removed the 7406 chip and its assosiated parts. I recommend the full version if you plan to do so.
SD CARD SETUP
1. Format an SD card to Fat32.
2. Download the Raspberry Pi Firmware from the Raspberry Pi Foundation.
3. Copy the files bootcode.bin, fixup.dat and start.elf (found in firmware-master\boot)) into the root folder of your SD card.
4. Copy over a file that contains a 1541 ROM image into the root folder of the SD card. The ROM must be called dos1541 or d1541.rom or d1541II or Jiffy.bin.
5. (OPTIONAL) Copy over a file that contains a CBM font ROM (eg vice-3.1\C64\chargen) into the root folder of the SD card. The ROM must be called chargen
6. Copy your disk images and folders into the 1541 folder now found on the SD card.
Or, simply download the below pre made setup and extract it to a SD card. You can start with that to be up and running right away.
The only difference between this setup and the one from my full version, is this setting in the options.txt file found in the root folder of the SD card: “splitIECLines = 1” must be changed to: // splitIECLines = 1
This project with PCB and parts can be purchased on ebay: https://www.ebay.com/usr/kirsti_73 or from Sellmyretro.com
Using a solder paste stencil is a quick way to get your production speed up when dealing with SMD parts (surface mount devices). At my house, its done because its fun and messy. But what exactly are they? A solder paste stencil is a metal or polymer plate with holes in it that represent the solder pads on your PCB.
All you have to do is to apply solder paste all over your stencil, remove it, and now a thin even layer of solder paste covers all your solder pads. Solder paste is liquid solder, often provided in a can or inside a syringe.
My preferred method is to place the target PCB in the middle of a wooden plate, align the stencil on top at the perfect spot, and later secure the target PCB with older PCS’s in all corners to keep it in place. Lastly, I have to secure the stencil in one corner perfectly aligned with the target PCB. If done correctly, I can now carefully replace the target as many times as I want, and flip the stencil over for a perfect fit with no hassle. I store it in a cardboard box for next time.
I decided it was time to make some kind of replacement for the bulky Amiga 500 RF modulator. This little thing has a nice composite output and a S-VIDEO output for great video quality. Unfortunately, the female DB-23 connectors are hard to find, so I wont be making many of these.
I figured the AD724 would do nicely.
A little about the AD724:
The AD724 is a low cost RGB to NTSC/PAL Encoder that converts red, green and blue color component signals into their corresponding luminance (baseband amplitude) and chrominance (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide composite video output. All three outputs can simultaneously drive 75 Ω, reverse-terminated cables. All logical inputs are TTL, 3V and 5V CMOS compatible.
I do have several PCBs and parts available, but since the DB-23 connectors are not easily available, I will only post the PCB for sale.