I'm trying to revive my old Apple II Europlus, but I have a trashed boot screen when I power it up. The speaker make the startup bip, but then it halt there. Eventually, some random noise happen in the speaker. Does this screen mean something, or it's just trashed?
It's not trashed. I'd be "reseating" all the chips to insure there is better connection in the sockets. You likely have oxidation on the pins after all these years, but there is also a chance a memory chip or (less likely) a ROM IC bit the dust.
Try carefully re-seating the IC's first.
ok, Il will do that. What do you mean with "it's not trashed" ? Does this pattern mean anything?
Except for the fact that something is not working correctly :-)
If you're getting a "beep" when powering on, then you know the CPU, ROM, and at least some of the RAM is working. My guess is that you are seeing the Page2 Text screen on the monitor instead of Page1. You could verify this with some simple commands typed in (blindly) such as CALL-151 and 800:B1 B2 B3 B4 and see if the characters in the upper left of the screen change.
If I'm correct, then the 74LS259 at location F14 would be the culprit. You could start by removing it and cleaning its pins. As others have said, this would be a good idea to do for all of the chips.
thanks for the tip, I will try that!
See also my earlier post about a problem that is comparable to yours: https://www.applefritter.com/content/apple-ii-europlus-help-diagnosing-no-prompt
What I have now is that some keys are self repeating for two or three times when I press them, but not all. Not sure if this is related, it's certainly another problem.
Many, many thanks for your help! Now my II europlus live again.
That's great news!
I think the key-problem could be a loose contact in the key switches maybe? And did you clean the keyboard IC socket on the motherboard? I use Kontakt 60 for that.