So I’ve bought a Macintosh classic II which powered to white bars and decided to go through recapping the logic board with tantalum caps as well as analogue board with low esr caps using recapamac.com.au/ as reference as well as dp3 and dp4. After the work I powered the macintosh and got the same white bars the first time I powered it and no screen output on second boot.
At this point I measured the logic board power connector pins and got the following voltages
1. 12v 12.13v
2. 5.07v
3. 5.07v
4. 0.23v
5. 3.32
6. 0v
7. 0v
8. -11.85v
9. 2.42v
10. 0v
11. 0v
12. 0v
I've worked on a macintosh classic previously and ordered a set of tda4605 chips and received tda4605-3 from aliexpress. After replacing tda4605-3 it powered for a few seconds with display then the main glass fuse blew and I later found a short on dp5 diode.
At this point I'm looking at replacing the mosfet, tda4605 from previous source and dp5 with another diode as well as qp1 with another octocoupler(as Philips CNY17g-3 doesnt seem to be available).
At this point I measured the logic board power connector pins and got the following voltages
1. 12v 12.13v
2. 5.07v
3. 5.07v
4. 0.23v
5. 3.32
6. 0v
7. 0v
8. -11.85v
9. 2.42v
10. 0v
11. 0v
12. 0v
I've worked on a macintosh classic previously and ordered a set of tda4605 chips and received tda4605-3 from aliexpress. After replacing tda4605-3 it powered for a few seconds with display then the main glass fuse blew and I later found a short on dp5 diode.
At this point I'm looking at replacing the mosfet, tda4605 from previous source and dp5 with another diode as well as qp1 with another octocoupler(as Philips CNY17g-3 doesnt seem to be available).