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Board A1342 2009, 820-2567, no audio, no chime

V

VinceLx

Member
Hello all,

This board works but it has no audio, not even the chime at start up. Prohibitory sign is displayed when trying to change the audio level.
No beep sound also if no memory installed.

In system preferences > sound: there is nothing for output or input.

If I plug a audio USB adapter, it appears in the above menu, and volume control works normally.

Some measures:

PP1V8_SO_AUDIO=1.8V
PP4V5_AUDIO_ANALOG=4.5V
PP5V_S3_AUDIO=5V
PP3V3_S0_AUDIO=3.3V
HDA_RST_L=3.3V

but
AUD_GPIO_3=0V, so is SPKRAMP_SHDN, and I understand that this is disabling all 3 amps 6610, 6620 and 6630

I was thinking about replacing U6201. Is this the good way? Other options?
 
Last edited:
2informaticos

2informaticos

Administrator
Staff member
"AUD_GPIO_3=0V, so is SPKRAMP_SHDN"
What do you expect there?
If 0V, means NO amp shutdown; do you want to mute it???

If no audio codec is recognized in system report, then change the codec; if has all power rails good.
Inspect for corroded traces and resistors first.
 
V

VinceLx

Member
I don't agree. For example the datasheet of U6610, LM48556TL, says for SPKRAMP_SHDN (pin SD*, number C3):
"Active Low Reset Input. Connect to VDD for normal operation. Drive SD low to disable."
So I expect 3.3V to avoid shutdown, no?
I don't find any corrosion. So, I change the CODEC, U6201?
 
2informaticos

2informaticos

Administrator
Staff member
I just saw that's truth.
Apple fucked off again a schematic.
Signal name should end with "_L", as active low signal.
Is only visible inside of chip marking (SD*).

I didn't even look at schematic, only thought on signal name; mea culpa.
Check HDA_RST_L first.
 
V

VinceLx

Member
In fact it is strange, because Apple put the "_L" for HDA_RST_L (tagged RESET* inside the chip), not on SPKRAMP_SHDN
Anyway, this HDA_RST_L is 3.3V. So chip is enabled, power rails ok, no corrosion: tomorrow I will try to replace my first 48 pin chip...
 
2informaticos

2informaticos

Administrator
Staff member
We cannot expect Apple, nor other manufacturer to simplify board repairs.
Watch Louis videos about "right to repair" hearings...
 
V

VinceLx

Member
No luck for this one, still no sound. Either the chip was also bad, or I fucked it, or there is another issue that I don't see at all.
I also checked that there is no short on SPKRAMP_SHDN on the amps, I measure 75kohm, seems ok.
So, for this one I give up :(
 
V

VinceLx

Member
I heated the MCP, now I get no video and no backlight (and still no sound, even without RAM).
I checked all the rails, they are still ok
Fan spins, no red light on mouse, just the peak when starting
PPVCORE_S0_CPU=0.99V
LVDS_IG_PANEL_PWR=0V
State should be S0:
SMC_PM_G2_EN=3.4V
PM_SLP_S4_L=3.32V
PM_SLP_S3_L=3.32V

Probably heated too much? I put 90 seconds at 450`C, only the MCP, I protected the remaining PCB with aluminium. What would be correct time and temperature? (I know, I should have asked that before)
Any idea to get back the video? Or is it fried now?
 
2informaticos

2informaticos

Administrator
Staff member
MCP damaged now, I suppose.
Heat test is about 10-15s at 180-200 degrees on the die.
I do this normaly with 400 on the hotair station, at few cm away.
However, depends of the tool used.
 
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