Quote:
Originally Posted by dominicbeesley
Are we sure the keyboard is playing up and not the video character RAM - I'm not sure how it works on the PET but a BBC Micro was showing similar behaviour in text mode (7) which turned out to be a dodgy DRAM - just a thought.
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It's an interesting thought; but if that were the case, you would expect the relationship between the "wanted" and "actual" characters to be different. Faulty memory would manifest as characters with similar bit patterns but one bit always set or never set; for example, if bit 4 were stuck "on" then you might get @→H, A→I, B→J, C→K ..... P→X, Q→Y, 0→8, #→: and so forth. When the relationship is that the "actual" character is in the same row or column of the keyboard matrix as the "wanted" one, it's more likely that the fault is at the stage of reading the keyboard.