Step 10.73 — Confirm dead¶
Step 74 of 80 · Chapter 10 — Wiring and Checkpoint #1
(no image — see text)
Gather for this segment — steps 10.73–10.79 (~20 min)
Tools and consumables
- multimeter
- multimeter on Ω
- room thermometer
Parts:
- multimeter · tool
Do: Cord out of the inlet and out of the room. Meter on DC V across the PSU's +V and −V.
Check
0 V, and it stays 0 V for ten seconds. The bulk caps are discharged.
What you're looking at
A PSU holds charge in its bulk capacitors after the cord comes out. Reading 0 V across its DC output, and watching it stay there for ten seconds, is what proves the machine is safe to probe.
Unplugged, AC lids on
every step in this section is measured with the cord out; nothing here powers anything on. Every probe point is outside the AC lids, so the sweep re-checks the closed mains side. A row fails: lids off, trace and fix, refit, repeat that step. LDO layout: every lid is still off.
Source: LDO wiring guide § Checkpoint 1