A1706 820-00239-A no power

hgoncalves

Active member
Hi,
I have an A1706 820-00239-A that has no power. The ampmeter doesn't even power on, so the mac doesn't pull any voltage

PPDCIN_G3H it's not shorted - 1k ohm
PPBUS_G3H is 13 k ohm
PPBUS_HS_CPU = 8 M ohm
PP3V0_G3H = 18 k ohm
PP1V8_SUS = 1.2 k ohm
PP1V2_S3 = 150 ohm

It had the DB500 broken, and I have already replaced (with the same result).
I can't see any oxidation, and don't have any history of it.
Can you help?
 
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hgoncalves

Active member
HI,

J3300
PIN 3 (XB_CC1) = 0.590V
PIN 53 (XA_CC2) = 0.203V
PIN 6 (XB_CC2) = 0.510V
PIN 52 (XA_CC1) = 0.580V

JB500
PIN 52 (TA_CC1) = 0.616V
PIN 6 (TB_CC2) = 0.625V
PIN 3 (TB_CC1) = 0.622V
PIN 53 (TA_CC2) = 0.617V
 

2informaticos

Administrator
Staff member
"PIN 53 (XA_CC2) = 0.203V"
This looks bad.
Check the components connected there.
Possibly bad C3215 chip.
 

hgoncalves

Active member
The cd3215C had a small burnt hole... I replaced and the short is gone, but still no power, and ampmeter powerd off.
PIN 53 (XA_CC2) = 0.600V and 12M ohm
Also the D3328 was broken and i replaced it. However i have 0V on diode mode and 100 M ohm of resistance in the pin 31 of the J3300
 
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2informaticos

Administrator
Staff member
Still black meter, not 5V?
Check XB_CC2 too; had low value before.
In fact this CD3215 pair has all values lower than other pair.
 

hgoncalves

Active member
Hi,
The amp meter is fully black. (now it tries to start, but immediately goes fully black. Very,very quickly almost not noted)). Previously, it was always full black).
PIN 3 (XB_CC1) = 0.600V
PIN 53 (XA_CC2) = 0.617V
PIN 6 (XB_CC2) = 0.510V
PIN 52 (XA_CC1) = 0.580V
 

2informaticos

Administrator
Staff member
XB_CC2 is still too low, comparing with the other lines.
Check diode protection, or corresponding CD3215 chip.
 

hgoncalves

Active member
Sorry, but I didn't understood what you meant by " Check diode protection, or corresponding CD3215 chip ". C3214 and DZ3351 seems to be ok. Shell I replace this CD3215?
PP20V_USBC_XB_VBUS seems to be shorted. On it i get 0.13 ohm of resistance and 0.0002mV on diode mode, and the D3370 seems to be a little decolourized (not sure).
 

hgoncalves

Active member
I can't find the R3370 on my schematics. Are you sure this is the one?
Already clean the pins, and i'm testing without the connectors but same result
 

hgoncalves

Active member
I lifted up D3370 and the pad was gone (burnt). The short disapered and so i made a jumper from C3354 pad, and solder the diode back again. The short is gone, but still no power (black meter)
 

hgoncalves

Active member
Hi,
I don't get any voltages on F3000/1, but something funny happens:
On one of the ports of J3300, if I flip the meter, the meter works and the mac puls 4.97V, and consumes 0.13A In this case, i get 5V on F3001, and 0V on F3000
 

hgoncalves

Active member
After replace U3200, now, on one port JB500, the meter shows 4.97B and 0.07A and stays powered on steady, and on all other ports, the meter starts for about 3 sec, shows 4.97V and them reboots
 
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