02020 ticking sound

grmacs

Member
This Mac has a ticking noise. At first I thought when I opened this and plugged it in it was coming from CPU but it is really hard to tell and there is no voltage showing at CPU coils. DCIN is 5.15V cycling at 40-80 mA. Spots of corrosion in many areas of board but not bad really in total. Worst was around U5200 so I reballed one from another board and replaced U5200. Just thinking there's such a high likelihood of no-fix on these boards. Want to know if there is a quick way to determine if I'm wasting my time. Not seeing any shorted big coils they are all .1 and higher when checking diode mode on big coils.
 

2informaticos

Administrator
Staff member
You may have a problem with a secondary power supply.
Do not insist with this board, if you have other jobs to do...
 

grmacs

Member
I ended up discovering that I was missing power at coils at L5800/20/40 but everything looked good up til that. Tracked down to U5700 which had enable signal. All diode readings regarding U5700 and coils compared correctly to another cloud locked donor. Regardless because of lack of outputs, I replaced U5700 and board now boots and ticking noise is now gone of course. Getting an ALS error in diagnostics and screen goes dim just before login. NOt sure if this could be a glitchy thing or not. DIode check of components at LCD connector all look ok. Tried another display but of course realized that ALS error will occur with foreign Apple display so that didn't help. I may just have the customer come in to login to see what display does. Display doesnt respond to flashlight at camera area.
 
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grmacs

Member
I poked around UD140 and components near LCD connections with diode test and compared to my donor, not seeing anything but could replace UD140 just to see. I don't have a way to test the webcam without the customer but maybe I should just wait until customer comes in as I'm thinking these M1's can flag an ALS error with no visable symptoms, correct?
 
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