MBP 820-3662 Power, no chime

[mgrharry]

Working on a MBP 820-3662 board. It had a bad battery and would only run off AC power. Also checked the logic board and found a small amount of liquid damage near DC in board, and one of the CPU screw mounts had popped off the board. Cleaned up corrosion and epoxied CPU screw mount. Popped replacement battery in and.... fuck, it powers on and fans spin for about 5 seconds, spin down, then spin back up and it stays on but does not post, no chime. Plugging in USB mouse shows only brief flash of light when USB is first plugged in. SMC reset done using internal kb does result in charging light change blink as per normal but otherwise has no effect. CAPS lock light does not respond. CPU gets warm after 5-10 min, but not particularly hot.

Some readings:
PPBUS_G3H = 12.68
PPVRTC_G3H = 3.36
PP5V_S5 = 5.09
PP5V_S4 = 5.09
PP5V_S3 = 5.09
PP5V_S0 = 5.09
PP3V3_S5 = 3.36
PP1V5_S0 = 1.52
ALL_SYS_PWRGD = 3.24
PPVCC_S0_CPU = 1.71

Tips anyone?

[piernov]

Re: MBP 820-3662 Power, no chime

PLT_RST_L?
Seems like issue with CPU. Any damage near CPU or CPU VRM chips?

[mgrharry]

Re: MBP 820-3662 Power, no chime

I hope it's not the CPU.... how to be sure?

PLT_RST_BUF_L = 3.35

[piernov]

Re: MBP 820-3662 Power, no chime

No idea, have seen people with that issue multiple times and never got it solved, just randomly assumed it's a CPU related issue (or PCH maybe). For the other cases I've seen, flashing/replacing SPI ROM or replacing SMC didn't solve it. Didn't see someone replace PCH or even CPU for that issue yet.
Maybe it's something completely different but at this point I don't have any clue.

[mgrharry]

Re: MBP 820-3662 Power, no chime

Smc_bc_acok = .85

bad smc maybe?

[piernov]

Re: MBP 820-3662 Power, no chime

It has green to orange light on Magsafe though doesn't it?