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OK. I will socket IC20 and 25 tomorrow. In the meantime, is there a better way (more logical way) of determining if those ICs are working correctly using a scope? The approach of desoldering and using a logic tester seems slightly extreme. This is my board: IMG_20260305_145142-edit-20260305145155.jp...

OK.
This is the 32k screen: ...and after 30 seconds I hear a click:
Pin 35 of the CPU: Pin 34 of the CPU:

Moving LK1 from South to North does affect the display. According to the technical manual, that is the 32/64k switch.
By SAM, do you mean the 783?
I'm afraid I don't live anywhere near Cambridge but I am happy to post this if my attempts prove fruitless...

Hi Rob, Thank you for the response. It is great to be hear. The Dragon is a wonderful machine and one that I would really like to explore, once I get this one working! Here is a screenshot of the display on startup: IMG_20260306_092930.jpg I did check the ROMs previously but have nevertheless upload...

Hi all, I recently acquired a Dragon 64 - after a mere 40 years of waiting - which unfortunately does not work. I have therefore been attempting to repair it. It produces a green screen on startup with a few characters. So far I have checked the following: 1. The 6809 CPU (using my Dragon 32) 2. 74L...