I got myself another Mac Plus and an additional logic board for a decent price. The machine is in good condition but does not work. The AB has battery damage inside the battery compartment and for whatever reason on the Optocoupler IC. I reflowed (nearly) every joint and tried powering it on. Unfortunately I only produces a clicking noise. The voltages on the floppy port are jumping around. Max 2,something V on the 5V line, same on the 12V. Only the -12V line produces the expected voltage. It seems that the power supply cannot start. I replaced the battery damaged optocoupler and Q11 next to it. I visually checked components for burn marks or something obvious, but had no luck.The logic board inside the machine works with my working Plus without any issue. The connector cable is fine and has no fuse.
This is the type of clicking produced by the AB.
View attachment macplus.mp3
On my other Plus I once had the "flup flup" error. I'm under the impression that the "flup flup" sounds different from what I now hear. I have to work through the Dead Mac scrolls book but would be happy if you have any advice.
The additional logic board is dead and worth another thread.
This is the type of clicking produced by the AB.
View attachment macplus.mp3
On my other Plus I once had the "flup flup" error. I'm under the impression that the "flup flup" sounds different from what I now hear. I have to work through the Dead Mac scrolls book but would be happy if you have any advice.
The additional logic board is dead and worth another thread.
