THE SHAREWARE PLUS COMMODORE 64 & 128 BLOG sent me two 1541 Trackdisplay kits, one kit for Track and one for Sector. Normally I don’t modify original cases, but it was already cut up at a few places by the previous owner so I thought it’d be ok to cut up a hole in the front.


An overlay sticker is included in the package to cover up the hole which gives a really nice finish. Mine looks currently a bit rough since I added a piece of plastic in front of the display to dim the display and I need to finish up the installation with a 4-digit 7-segment display bezel, or make a custom sticker later on.

The kit is available for 1541/1541C/1541-II/1571/1581/C128D/C128DCR and requires some DIY. Everything is through-hole soldering and the manual covers the assembly in detail, you will not have any surprises or trouble assembling everything together. Soldering the The 7-segment display LED cables requires some patience though :).

This display supports displaying the current track AND/OR sector(or any memory location) which is an advantage compared to other solutions when studying loaders for example (nothing beats code reversing!). The display(s) will show “00” on intialization as the memorylocations are not yet populated, but its not a problem.

 

From the Manual:
The Track Display is memory based, ie. the memory cells relevant for the respective drive types are monitored for change in real time. During write access to the memory cells, the hexadecimal data value of the memory cells is decoded and output via the 7-segment displays connected to the display drivers CD4511. The address selection and the decoding of one and / or several addresses are handled by an EPROM which has been programmed as a gate array. Theoretically, this design allows arbitrary memory cells to be represented by the SRAM of the floppy: track, sector, buffer pointer, status register – simply everything that is stored in the floppy RAM. Also, cascading several boards by stacking is possible, e.g. Track + Sector. For the sector display only a differently programmed EPROM is required.

 

You will get a nice package with all needed components and a manual.

 


Populated PCB, 7-segment display connectors(IC sockets) are located on the rightmost part of the PCB. I installed a passthrough-socket for the RAM since the boards will be stacked. I also always install IC sockets as a routine. The sockets, however, added some height to the installation and caused me a bit of a problem later on.
 
The decimal points(DP) will be used to display which ROM is active and to show when drive is exchanging data with the computer. Wires and resistors for accessing the DP are present on the PCB.
 


Both ends of a 7-Segment-display cable. Shrinking tubes used on the wires to isolate and stabilize. The display and the socket are not 1 to 1 pin compatible so you need to cross a few wires (documented in the manual).

 


Some drives have large ceramic capacitors which can be replaced with smaller ones or, if space allows, bend them down a bit. They can be moved to the bottom side of the drive PCB in worst case.
 

Another approach is to add empty socket(s) to lift the PCB above the capacitors (picture is for illustrative purpose only).

 

 

 

Track AND sector trackdisplay PCB in place, stacking them became too high to fit under the lid, possibly because I added IC-sockets.

 

The kit allows for some DIY and there is lots of space in a 1541 drive. I connected the PCBs together with a ribbon cable and wedged the memory IC below the first board.

 

Installed a DolphinDOS under the Track/Sector display just out of curiosity. When resetting a DolphinDOS drive the display defaults to “77” or shows a “blank” display, probably to do with how memory is initialized. DolphinDOS mode runs too fast for the sectors to be readable on the display, not a big surprise though :).

 

Inside the lid, cables and glue.

 

 

First part is fast formatting a disk, and second is loading a game where it switches to a fastloader after a while. The video does not quite do justice for the 7-segment LED display as it is more distinct in reality and no ghosting can be seen on the led segments.