Hi,
My friend just got a Mac Plus, which was dusty but not obviously corroded anywhere; after cleaning and checking +5 V (4.98) and +12 V (12.15) rails, she powered it on and saw this:
View attachment IMG_0797.mov
With 1 MB and 4 MB of RAM from her SE/30, it shows these (respectively):
All symptoms are consistent for the given RAM configuration, and she cleaned and tightened RAM/ROM sockets and tried swapping high/low ROMs to no effect.
We've looked at this post which suggests bad RAM (unlikely given the above?), ROM, or the 6522 chip. It seems like a logic board rather than analogue board problem?
Please advise -- any points on the board to check which would help indicate the issue? Are there other likely causes? Is replacing the 6522 or ROMs a reasonable next step? Does the consistent behavior with each amount of RAM tell us anything?
Here's a photo of the logic board:
Thanks!
My friend just got a Mac Plus, which was dusty but not obviously corroded anywhere; after cleaning and checking +5 V (4.98) and +12 V (12.15) rails, she powered it on and saw this:
View attachment IMG_0797.mov
With 1 MB and 4 MB of RAM from her SE/30, it shows these (respectively):
All symptoms are consistent for the given RAM configuration, and she cleaned and tightened RAM/ROM sockets and tried swapping high/low ROMs to no effect.
We've looked at this post which suggests bad RAM (unlikely given the above?), ROM, or the 6522 chip. It seems like a logic board rather than analogue board problem?
Please advise -- any points on the board to check which would help indicate the issue? Are there other likely causes? Is replacing the 6522 or ROMs a reasonable next step? Does the consistent behavior with each amount of RAM tell us anything?
Here's a photo of the logic board:
Thanks!
