19/09/2017
Important test steps when repairing
1. Power Source Test:
- Most mains do not need CPUs (except for some INTELs that require a new CPU
).
- If the source is not tested try to remove the 12V (4pin) jack if you can, then the problem is
100% in the VRM circuit is short. - Squeeze: If the fault is just an island mosfet or something light, press squeeze will run normally.
Pressure
or not hit, then hit hard. - Measure 5V (or 2v5 -> 5V) at PS-ON battery.
If lost: Battery Detector PS-ON -> Chip NAM or
SIO. That guy beat that guy. (If the test chip, the source NAM and instead try quartz
chips anymore offline)
- Detect mosfet island (or IC Island): Green foot -> (last) island port (or direct) -> SIO; Dam
gates or SIO island.
Major damage: dead island mosfet, SIO error, NAM chip error.
2. Clock pulse:
- Run as soon as you click on the source without needing to plug in the CPU, check the clk and fix immediately step 2. Usually just cough, change quartz and replace IC clock is all.
3. Check the source levels:
- Vcore; VRM circuit