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820-01949 - No visible damage

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down1nit

Member
Came in with no damage seen, both sides of board and case. Powered on as soon as I put my ammeter in, pulled 20v booted just fine, was charging battery etc. Chalked it up to bad luck and put it back together, now it doesn't work again. Now it pulls only .063A and does not loop boot.

1v5 LDO .460 diode mode on all 4 chips
3v3 LDO .449 / .460 all 4
PPBUS present at 0.6V

My readings for PPBUS are strange. Measured at the ppbus fuse it climbs from 0 resistance to 5k resistance. I've seen this before, it's normal? Diode readings are similar: .320v to .420V over 10 seconds
 
2informaticos

2informaticos

Administrator
Staff member
Do you have known good battery connected?
This board model may not boot at all without battery.
 
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down1nit

Member
Battery seems deadish. 200ma at c6960 pin 1. Is there a way to measure before the battery fets or do i just swap
 
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down1nit

Member
Did a swap, i hate these batteries. Same deal with known good batt. It pulls 5v .0063 A but SOMETIMES it grabs 20v and sticks at 100ma with either battery, connected or disconnected. I leave it connected for 20 mins and it'll negotiate eventually. Though now it won't. Tempted to put it in a reflow oven just to see. Sigh.
 
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down1nit

Member
Doesn't seem to want to go to DFU, even using DFU force pads. Immediately settles at 5v .0045A draw now. Does not fluctuate, now doesn't get to 20V no matter how long. I hate apple.
 
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