jerjerbinx
New member
Wondering if anyone could help diagnose this issue I'm having with my Mac Classic. (video attached of symptoms on screen). I scoured the forum, but didn't see anything similar mentioned.
I pulled my Classic out of storage and booted it up. HDD spun up, OS7 loaded, video looked good and everything appeared fine...all 4k of RAM was reported... except there was no sound, so I figured there were leaky caps.
I opened it up to look around and, fortunately, there was minimal leaking on the logic and analog boards.
I should note that this Classic has a RAM expansion board installed. This has worked without issue up until the day I was set to recap the board. Before doing ANY work inside, i booted it up the machine one last time and out of nowhere got a sad Mac error "00000005 00100000". I pulled the ram expansion board and the Mac booted just fine with the OS reporting 1k of on-board RAM.
So, I proceeded in re-capping the logic board first and gave it a good cleaning. I booted it back up and it had sound finally, but it immediately had this persistent horizontal noise/distortion (hsync?) on the screen. The RAM module sad mac error was still persistent, but only with the RAM expansion installed.
I then re-capped the analog board. Booted it back up and still had the same video issue.
I checked the voltage on the 5v and 12v rails, and they were both reading correctly.
I then went over all of the solder joints on the analog board, checking the flyback and logic board power and re-flowed a few that could be suspicious, but everything looked ok.
Booted it back up and same issue.
I feel as though this is an issue somewhere with the logic board, as this wasn't happening before I re-capped it. Perhaps the cleaning process gave failure to something?
From what I understand, the RAM expansion error is related to a failure in the 74LS174 IC... Could this also be related to the video glitches?
Any insight or ideas would be greatly appreciated!
I pulled my Classic out of storage and booted it up. HDD spun up, OS7 loaded, video looked good and everything appeared fine...all 4k of RAM was reported... except there was no sound, so I figured there were leaky caps.
I opened it up to look around and, fortunately, there was minimal leaking on the logic and analog boards.
I should note that this Classic has a RAM expansion board installed. This has worked without issue up until the day I was set to recap the board. Before doing ANY work inside, i booted it up the machine one last time and out of nowhere got a sad Mac error "00000005 00100000". I pulled the ram expansion board and the Mac booted just fine with the OS reporting 1k of on-board RAM.
So, I proceeded in re-capping the logic board first and gave it a good cleaning. I booted it back up and it had sound finally, but it immediately had this persistent horizontal noise/distortion (hsync?) on the screen. The RAM module sad mac error was still persistent, but only with the RAM expansion installed.
I then re-capped the analog board. Booted it back up and still had the same video issue.
I checked the voltage on the 5v and 12v rails, and they were both reading correctly.
I then went over all of the solder joints on the analog board, checking the flyback and logic board power and re-flowed a few that could be suspicious, but everything looked ok.
Booted it back up and same issue.
I feel as though this is an issue somewhere with the logic board, as this wasn't happening before I re-capped it. Perhaps the cleaning process gave failure to something?
From what I understand, the RAM expansion error is related to a failure in the 74LS174 IC... Could this also be related to the video glitches?
Any insight or ideas would be greatly appreciated!
