The DesTest MAX-Switch Select cartridge expands upon the regular 'Switch cartridge by adding the capability to select between up-to 6 diagnostics programs. You may program the 28F512 PROM with up to 2 16K 'Switch images, 2 8K /GAME (MAX) images and 2 8K /EXROM images. You can use the two slide-switches to select between the six available images at your whim. This cartridge is your one-stop-shop for all your diagnostic program needs. Visit the DesTest MAX-Switch-Select page on my website for more details.

'Switch Mode

The custom DesTest MAX-Switch cartridges add the capability to switch (hence the name) between the MAX-mode and regular cartridge-mode under program control. This is very advantageous for diagnostic programs since it allows the machine to be taken-over right at power-up and lessens the reliance on the ROMS and other system hardware.

DesTest MAX-Switch Software

The DesTest MAX-Switch software includes the following features:

•   Full 64K memory test using the March-B algorithm.
•   No dependence on the ROMs, CIAs or SID: they can be removed.
•   ROM checksum verification (if they are installed).
•   CIA TOD consistency verification.

Dead + Diag FOM '26 Software

The Commodore DeadTest (781220) and Diagnostics (586220) have been reworked slightly and combined as a single 'Switch image. Under this arrangement, DeadTest will run at power-on, then, if there are no errors, will automatically switch-over to Diagnostics in order to test the rest of the system. While the inner-workings of these tests has not been changed, several bugs were identified and fixed. In addition, since this is a 'Switch image, Diagnostics will run fully and correctly even if there is no kernal or BASIC ROM installed.

The Hardware

The DesTest MAX-Switch hardware provides the following:

• Power LED. Most of the time when diagnosing or repairing a C64, the keyboard is removed along with the Power LED. The DesTest MAX-Switch cartridge includes a simple power LED to avoid mistakes like removing or inserting ICs with the power on.
• Reset Switch and LED. A faulty reset-circuit in a C64 can prevent it starting-up properly. A reset-switch can temporarily bypass a faulty reset-circuit and the LED gives a visual indication if something is wrong!
• Mode Slide Switch. The switch on the left-hand side of the cartridge selects what kind of diagnostic-image will run at power-up. Use it to pick between a 16K 'Switch image, an 8K /GAME (MAX) image or an 8K /EXROM image.
• Bank Slide Switch. Each of the three kinds of images (switch, game and exrom) can have two images installed. The right switch selects between these two images.

Extras

It is recommended that you download the included switch-v3.t-hardware_PCBWayCommunity.zip file before you order your PCBs (See Other Files for Assembly near the top of the panel to the right). This file includes detailed assembly instructions, an interactive BOM, 3d-printer files for a suitable cartridge-case and an example PROM image to use. The documentation also explains where to place alternate program images in the 28F512 PROM to customize your diagnostics selections.

Please read the DesTest MAX-Switch Licence agreements (LICENCE,pdf and HW-LICENCE-v2.pdf included in the above .zip file) before ordering your PCBs. Ordering PCBs will be considered as accepting the Agreements.

You may also be interested in the 'Switch v2 (DesTest MAX-Switch on factorofmatt.com) project which is a slightly updated version original 'Switch cartridge. The PCB is somewhat smaller, has less components and is a little easier to build. Find the PCBWay Shared Project here: DesTest MAX-Switch Cartridge on PCBWay