68kMLA Classic Interface
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| Click here to select a new forum. | | Macintosh Portable Power Up Issues - Display Flashes Once | Posted by: SteveHere on 2021-01-15 11:20:32
Hi All,
I'm trying to repair another Macintosh Portable. Non backlit version. I've done the recap, there were a couple of lifted pads that I think I've properly bodged using the Schematic that TechKnight and others have pointed too in previous posts.
Here's a video of what the computer is doing...
https://drive.google.com/file/d/1xHyM52mSeDQvC__K5vl5rsOiGnJZdsC_/view?usp=sharing
To summarize, the first time power is applied (Using a full battery in the case), Press RESET and NMI at the same time, press a key on the keyboard to power on, the screen flashes briefly, and then powers off. It won't repeat this behavior until all batteries / power adapter are unplugged, reconnected, then this cycle can be repeated.
I've read in other posts about the Hybrid and Power Manager, is that the part of the board I should be concentrating on?
Thanks,
SteveHere
| Posted by: bibilit on 2021-01-16 02:30:04
Hybrid probably.
A lot of issues when this is contaminated or bad
| Posted by: desertrout on 2021-01-16 08:17:39
Possibly the hybrid or PMGR IC (they are on opposite sides of the board FYI), could be other causes as well - electrolytic residue, bad traces, other bad / failing IC's like the SWIM... Have you checked the voltages on the 12V and 5V lines?
For a crazy amount of reference:
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