Hello!
I have a Mac Classic that refuses to start up. I received it after being battery bombed, and have purchased a new logic board, but before that can be installed I want to make sure that the AB is behaving. I have changed every electrolytic cap the board, as there were some signs of leakage from the usual cluster, and cleaned the board afterwards.
The analog board is model 820-0395 and shows little signs of life. Measuring the molex connector for the hard disk shows 0 volts. The fan doesn't spin. The only thing that I can see is that pin 6 of the TDA4605 has a fluctuating voltage of between 0 and 8 volts AC, which suggests to me that the board is trying to start up but something is stopping it.
I have checked the fuse, and replaced diodes DP1, 3 and 4. I have also installed a new TDA4605, CNY17G optocoupler and IRFBC40 mosfet. I have reflowed the solder around the larger joints and tested for continuity from the AC input, so the socket where it goes into the board seem to be fine. Nothing seems to help and whatever I do doesn't seem to progress any further.
Of course these boards are notorious for having problems and there are going to be a number of things that could be the issue, but I'm wondering if - given the information I have provided so far - I might have simply missed something else?
Thanks!
I have a Mac Classic that refuses to start up. I received it after being battery bombed, and have purchased a new logic board, but before that can be installed I want to make sure that the AB is behaving. I have changed every electrolytic cap the board, as there were some signs of leakage from the usual cluster, and cleaned the board afterwards.
The analog board is model 820-0395 and shows little signs of life. Measuring the molex connector for the hard disk shows 0 volts. The fan doesn't spin. The only thing that I can see is that pin 6 of the TDA4605 has a fluctuating voltage of between 0 and 8 volts AC, which suggests to me that the board is trying to start up but something is stopping it.
I have checked the fuse, and replaced diodes DP1, 3 and 4. I have also installed a new TDA4605, CNY17G optocoupler and IRFBC40 mosfet. I have reflowed the solder around the larger joints and tested for continuity from the AC input, so the socket where it goes into the board seem to be fine. Nothing seems to help and whatever I do doesn't seem to progress any further.
Of course these boards are notorious for having problems and there are going to be a number of things that could be the issue, but I'm wondering if - given the information I have provided so far - I might have simply missed something else?
Thanks!
