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820-00164 not working after ultrasonic.

K

Kyle93

Active member
Arrived with liquid damage not turning on. Replaced R5167 R5181 R5002 U5110 R5127 C5120 U1950 R1961 R1960. Afterwards had fan spin and booted into OSX no problem.

After ultrasonic with crest there is no fan spin and all rails including PPVCC_SO_CPU only pulse for a second. Havens run into this issue before.

All termination resistors measure good and have good continuity.

Any ideas?
 
2informaticos

2informaticos

Administrator
Staff member
Something happened in the ultrasonic process.
Maybe knocked off component, or broken trace...

Do you get pulse at pin 7/U1950 and PLT_RESET_L?
 
2informaticos

2informaticos

Administrator
Staff member
Check all the traces between replaced components.
Try to start in SMC bypass mode.
Also try the board disconnecting LIO flex, airport card and SSD.
 
K

Kyle93

Active member
Traces from replaced components have been checked multiple times and are good.

No luck on SMC bypass or disconnecting LIO flex. Airport card and SSD also removed
 
K

Kyle93

Active member
Noticed a pattern on this board. If U1950 is removed board powers up with fan spin but only draws 140-150 miliamps however once U1950 is soldered back to the board i gos through the same symptoms of no fan spin and powers rails pulsing. Tried multimple U1950s with same sympoms

Any ideas? Traces tested and good
 
K

Kyle93

Active member
Can a ultrasonic cleaner ruin the board internally if it is left in it for too long? I know this board was left in more then 10 minutes today after the process was completed by mistake. Cant find any bad traces and continuity is good on everything that was replaced. Checked multiple times. With everything on the board it draws 26-50 milimps for a few seconds, goes to 0 then continues. At moments it might go up to 170 miliamps.
 
2informaticos

2informaticos

Administrator
Staff member
The board cannot work without U1950; PCH needs PM_PCH_PWROK and PM_PCH_SYS_PWROK.
Try removing U8130.

UC can damage the board, especially if no sweep option is used.
Hot spots can break traces, or knock off components.
 
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