I came in to radio time tonight and had some power on issues:

Power Supply: Yaesu FP-1030A (maybe 4y old)

2m Radio: Yaesu FTM-310D (6m old)

HF: Yaesu FTdx10, bought used, owned about 2 years

All wired in together on the main 25A lugs, sometimes both on at the same time, never transmit at the same time.

For context: this supply lives in a closet that also houses my NAS. Reviewing the NAS's monthly SMART log, I noticed one recorded temperature peak about a month ago that came within 1°C of the alert threshold — it never triggered the automated warning email, and I'm not convinced this is actually related, but flagging it since it's the only anomaly in that timeframe.

My working theory: the trips seem to follow current transients (cold power-on inrush, CW key-down) rather than sustained load — steady receive current and hot-plugging the radio in didn't trip it, but power-on and keying did. Wanted to lay that out up front in case it points anyone in a faster direction.

Initial fault noticed — powered on the FP-1030A, overload light on, nothing powered up. 

Disconnected both radios (2m and HF); overload light cleared.

2m isolation test — plugged in only the 2m radio. It powered on fine, but power-cycled mid-transmit.

Connection tightening — tightened the screw terminal connections on the supply. 

Afterward, the 2m radio seemed to work normally for a period.

HF reintroduced alongside 2m — wired the HF radio back in alongside the 2m (the configuration that had worked since initial setup). 

Overload light came on immediately and neither radio would power on.

HF-only test — with just the HF connected, the radio operated normally on receive initially, then power-cycled during receive (no transmit involved).

CW transmit test — keyed CW at 50W (not full 100W). The supply cut out on the very first dit.

Physical/visual inspection — Power Supply: removed the top cover (12 screws), inspected the pass transistor heat sink assembly, sense resistor board, control board (including visual location of RV1), transformer, and capacitor bank. No visible heat discoloration, cracked joints, or obvious damage found. Noted general dust but nothing indicating a hot spot. 

The supply's own glass tube fuse looks clean and intact.

In-line fuse inspection and cleaning — pulled the two in-line fuses on the HF radio supply wires, dry-abraded the blades with folded printer paper (no solvent/cleaner used), and confirmed visible oxidation residue transferred to the paper despite the blades looking clean beforehand. Cleaned blades only — did not clean the fuse holder's internal jaw contacts, and no anti-corrosion contact treatment (e.g., DeoxIT) was applied.

Post-cleaning retest, HF only:

Powered on the supply with the HF already wired in — overload tripped immediately on power-up, before any transmit.

Powered off, disconnected the HF radio — overload light cleared.

Reconnected the HF radio with the supply already powered on (hot-plug) — no overload trip.

Powered on the radio itself and pressed Tune at 50W — supply cut out again.

I'm thinking I'm looking at a failure of the power supply (not the radios), but this is a new problem for me. Does anyone have any advice short of a big hammer or high speed introduction of lead?