Hey,
Got a liquid damaged A2337 on the bench (board 820-02016 rev 4.0.0) and I'm hitting a wall. Looking for input before I keep tearing into it.
What's been done already: U5200 (ISL9240HI) was oxidized. Reflowed it first, didn't fix it, ended up replacing it. Q5240 was running at 70°C so I swapped it too. Replaced a few obviously dead passives in the oxidized area before any of this.
Board pulls 60 mA stable on USB-C. No battery connected.
Rails that are good:
What U5200 is doing:
Downstream of that: P3V8AON_PWR_EN is 0, which makes sense since CHGR_EN_MVR never latches high. P3V8AON_FAULT_L sits at 0.63 V because Iceman has no input.
Where I think I am:
This board is supposed to boot from USB-C without a battery. In that case U5200 should pre-charge PPVBAT_AON_CHGR_REG through its internal reg and CHGR_VBAT should come up to something usable. Mine just sits at 0.289 V, which is what's tripping the charger into hiccup.
So either:
Questions for anyone who's done a few of these:
Got a liquid damaged A2337 on the bench (board 820-02016 rev 4.0.0) and I'm hitting a wall. Looking for input before I keep tearing into it.
What's been done already: U5200 (ISL9240HI) was oxidized. Reflowed it first, didn't fix it, ended up replacing it. Q5240 was running at 70°C so I swapped it too. Replaced a few obviously dead passives in the oxidized area before any of this.
Board pulls 60 mA stable on USB-C. No battery connected.
Rails that are good:
- PPDCIN_AONSW 5.12 V
- PPVBUS_USBC0 5.13 V
- PP3V3_UPC0_LDO 3.43 V — Ace2 is alive
- PPBUS_AON 5.16 V solid
- PPCHGR_VDDA 5 V
- PPCHGR_VDDP 4.92 V
What U5200 is doing:
- CHGR_VBAT 0.289 V
- CHGR_CSO_P 5.17 V
- CHGR_BGATE 5.16 V
- CHGR_AUX_OK 1.28 V (pulled up to PP1V8_AON_MPMU which is 0 V, so this reading is basically leakage, ignore it)
- CHGR_EN_MVR pulses to 0.18 V for about a second, then drops to 0
- CHGR_RST_IN 0 V, no short (3.01 MΩ to GND)
Downstream of that: P3V8AON_PWR_EN is 0, which makes sense since CHGR_EN_MVR never latches high. P3V8AON_FAULT_L sits at 0.63 V because Iceman has no input.
Where I think I am:
This board is supposed to boot from USB-C without a battery. In that case U5200 should pre-charge PPVBAT_AON_CHGR_REG through its internal reg and CHGR_VBAT should come up to something usable. Mine just sits at 0.289 V, which is what's tripping the charger into hiccup.
So either:
- something is pulling the VBAT rail down (cap shorted partial, dead FET leaking, etc.)
- R5260 (5 mΩ shunt) is open
- Q5265 (BGATE FET) is dead even though gate is driven
- something on the BMU side (J5150, Q5155, D5150) is dragging the rail
Questions for anyone who's done a few of these:
- Anyone seen this exact behavior on a 820-02016 specifically?
- Does this board actually boot cleanly with no battery, or do you guys always plug in a battery / simulate one with a bench supply?
- Any known weak spot on the VBAT rail with liquid damage on this model? Cap that's notorious for going short, etc.
