820-00165 Board Repair

[Instafixx]

PPBUS_G3H is 8.57
PP3V42 is 3.4V
ALL SYS PWRGD is 0V
U1950 all pins 0 Volts
PP5V S4RS3 PULSING
PP3V3_S5 IS 3.3V
PP5V_S5 IS 5V

BOARD HAS BEEN WORKED UPON PREVIOUSLY.
A FEW COMPONENTS MISSING WHICH WERE RESTORED. (C1260/1/2)

SMC ALSO REFLOWN/CHANGED

 

[2informaticos]

"U1950 all pins 0 Volts"
Pin 8 MUST have voltage; is directly connected to 3V42_G3H.
Rebuild broken trace...

 

[Instafixx]

Sorry i meant all pins except Pin 8. getting 3v42

 

[2informaticos]

"PP5V S4RS3 PULSING"
Any big coil pulsing at same rithm?
Check in SMC bypass; this should provide higher pulse.

Do you get 1-2 pulses, or continuously every 5s?

 

[Instafixx]

PP5V S4RS3 - It pulses continuously every 2-3 seconds.

Other Big Coils ( CHECKED WITH RAW BOARD ON TABLE)
L7560 3.3V STABLE
L7430 PULSES BETWEEN 0V TO 0.8V EVERY 2-3 SECONDS
L7630 PULSES BETWEEN 0V TO 0.7V EVERY 2-3 SCONDS
L7320 PULSES BETWEEN 0V TO 1V EVERY 2-3 SECONDS
L7310 PULSES BETWEEN 0V TO 1.1V EVERY 2-3 SCONDS
L7130 STABLE 8.57 VOLTS
L3095 0V

IN SMC BYPASS - PP5V S4RS3 IS SAME. PULSING FROM 0V TO 3.9V

 

[2informaticos]

So you get pulse on CPU core too.
Check for pulse at pins 7 & 3 of U1950; also PLT_RESET_L.

Please, use capital letters when really need only...

 

[Instafixx]

Yes Pin 7 and 3 are pulsing

Pin 7 to 2.2V and Zero
Pin 3 to 1.5V

PLT RESET L is stable at 0V.

 

[2informaticos]

What about CPU_VCCST_PWRGD and CPU_VR_READY?

 

[Instafixx]

CPU_VCCST_PWRGD pulsing from 0.5V to 0V.
CPU_VR_READY pulsing from 0.6V to 0V

 

[2informaticos]

Possibly CPU issue.

Check all SPI Bus Series Termination resistors and their traces.
Inspect J6100 for corrosion.
Heat CPU with quality flux; in case of accumulated crap underneath.