This is the official home page for Commodore Repair Toolbox (named as CRT hence forward) - a Windows utility tool for repairing vintage computers or peripherals.

Main screen with schematic view:

Component information popup:

Oscilloscope baseline measurement:

With CRT you can easily view schematics, zoom in/out, identify components, see chip pinouts, do manual circuit tracing, study datasheets, view oscilloscope readings, ressources and various other information, helping you diagnosing and repairing old vintage hardware.

It is primarily dedicated to Commodore, and have a few built-in datasets for Commodore computers, but it does support any kind of hardware, as you can add your own data - e.g. other computers, radios, DIY electronics or whatever else you can imagine. It probably works the best, if the hardware is "simple" and have good documentation available, like schematics, and if it is something you need to revisit multiple times - then you can add the needed information yourself, and use it for easy future reference.

• Windows 10 (64-bit) or newer
• .NET Framework 4.8.1 (integrated part of the operating system)

CRT does not require any installation - just download the newest ZIP file from Releases, extract it and run the executable file, Commodore-Repair-Toolbox.exe

• Commodore VIC-20
  • 250403 (CR)
• Commodore 64
  • 250407
  • 250425
  • 250466
  • 250469
• Commodore 128 and 128D (C128D plastic model, not DCR)
  • 310378
    • Has full oscilloscope baseline readings for a PAL system

I would really appreciate if some seasoned Commodore experts would take a brief look, and let me know of obvious factual errors or things I have missed, as ideally this tool could be used by many as a helper-tool, keeping our beloved Commodore hardware running 🙏

You can also help specifically with these topics:

• Do you have higher-quality images of the used schematics?
• Do you have (better) datasheets or pinouts for any of the components?
• Do you see missing components in either the component list or as a highlight?
• Can you improve any data or fill in more technical details anywhere?
• I have done some oscilloscope baseline measurements on a good working PAL system - would you be able to assist with the same reading on a NTSC system?
  • Please connect with me, so we can coordinate on what and how to measure.

You can also contribute by adding new data and send the Excel file and "label file" to me (view Wiki Documentation for how to use the labeling software).

You can create a new Issue here in the GitHub project page or use the built-in "Feedback" tab, if you want to report a problem, suggest any changes or just have a comment. I would appreciate some feedback, to know if this is actually useful for others or if you see some missing functionalities that could be benefitial for many.

Please refer to the Wiki Documentation page for adding or modifying the data.

I have taken data from many places, but I do have a few go-to places I frequently visit:

• My Old Computer (view below also)
• Zimmers
• Ray Carlsen

In some cases I provided or modified the data myself, which is why some expert facts-check would be very much appreciated.

If you want to contribute with a major new or updated dataset, then please let me know, as I happily will show credits here for joint efforts. There is a large Commodore community, and I wish for collaboration into making this a great reference for Commodore reparing (well, on the Windows platform at least).

I have been repairing Commodore 64/128 for some years, but I for sure still consider myself as a beginner in this world of hardware (I am more a software person). I often forget where and what to check, and I struggle to find again all the relevant ressources and schematics to check, not to mention how to find the components in the schematics. I did often refer to the "Mainboards" section of My Old Computer, and I noticed that Jeroen did have a prototype of an application named Repair Help, and it did have the easy layout I was looking for (I did get a copy of it). However, it was never finalized from him, so I took upon myself to create something similar, and a couple of years later I did come up with a very similar looking application, also utilizing some data directly from Jeroen's page (with permission from him, of course).

For now I will continue to add new and refine data for myself, when doing my diagnostics and repairing of Commodore equipment, and then I can only hope that others will take the initiative and time it takes to add additional hardware or help refine the existing data - then I can have this data available somehow at the project home page.