I have been working on a Mac IIx motherboard that will not boot. I have repaired the startup/ shutdown circuit and it will turn on by pressing the power button. However, I do not get a boot chime nor video. There was slight battery corrosion and slight capacitor corrosion near C9. Nothing major and that repaired my startup/ shutdown circuit.
I had thought that it may be a ROM issue because I have booted without a ROM stick on my other Mac IIx and I would get a similar result of no chime, no video. I have changed the ROM socket and I am getting voltage to the pins. I wish there was a bomarc schematic for the Mac IIx so I could follow traces for each pin.
My Flir camera shows activity. I also see heat from the CPU. I have another Mac IIx and the heat pattern is similar except for the area around Q1. I have replaced it and it looks like there is activity, but still cold.
I am stumped with this one. Any help or guidance would be appreciated.
My image a Flir image of my working Mac IIx, middle is Flir image of the board I am working on with the red circle and last is image of the board.
I had thought that it may be a ROM issue because I have booted without a ROM stick on my other Mac IIx and I would get a similar result of no chime, no video. I have changed the ROM socket and I am getting voltage to the pins. I wish there was a bomarc schematic for the Mac IIx so I could follow traces for each pin.
My Flir camera shows activity. I also see heat from the CPU. I have another Mac IIx and the heat pattern is similar except for the area around Q1. I have replaced it and it looks like there is activity, but still cold.
I am stumped with this one. Any help or guidance would be appreciated.
My image a Flir image of my working Mac IIx, middle is Flir image of the board I am working on with the red circle and last is image of the board.