fabrizio Posted February 18 Share Posted February 18 (edited) Ciao everyone. I have this issue. When it starts cold, you can see characters flashing (video). If try to heat up the 7400 (C15) or the 74175 (C13), it start working fine: clear screen, rset ok, 480 nS and 3,5 uS perfect.Of course, I've tried replacig them. grazie VID_20240209_185251.mp4 Edited February 18 by fabrizio Quote Link to comment https://forums.atariage.com/topic/361607-apple-1/ Share on other sites More sharing options...
ClausB Posted February 21 Share Posted February 21 (edited) The difference between P and 0 in ASCII is 20 hex (likewise @ and space), so look for problems with data line D5. Is the video RAM divided up into bits? If so, there may be a bad RAM chip. Those are old shift registers, maybe hard to get. Is your Apple I original or a replica? Edit: Normal cursor function is to flash between @ and space, so maybe the problem is in the cursor circuit. Edited February 22 by ClausB Quote Link to comment https://forums.atariage.com/topic/361607-apple-1/#findComment-5415670 Share on other sites More sharing options...
ClausB Posted February 22 Share Posted February 22 7408 at C12 and 74174 at C7 are also part of the cursor circuit. Quote Link to comment https://forums.atariage.com/topic/361607-apple-1/#findComment-5415757 Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.