[SOLVED]820-00165 - No 3.3V on Pin1 of SPI-ROM

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bjf

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Liquid-damaged. Light corrosion in a few places (see pics) including the area around the SPI ROM chip. SPI_SMC_CS_L is measuring 1.38V instead of 3.3V. PPVRTC_G3H is measuring 3.3V.
PP3V3_S4 is at around 0.3V, then it slowly drops, and then jumps up to 3.3 for split-second. SYSCLK_CLK25M_X1 is at 0.8V and SYSCLK_CLK25M_X2 is at 0.06V. Because I don't know if you should have a clock at this point I replaced U1900 and Y1905. Not sure where to go next.
 

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bjf

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Ok, I'll have to make a request to Louis to change the image upload converter settings for the forum. The pics are high-res but are getting dumbed down. There is corrosion around U6100. I cropped the pics and uploaded them. Hopefully they're somewhat useable.
 

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bjf

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Ok, I don't like to work on them until I clean them in the ultrasonic so any previous notes were after cleaning. I checked all of the lines in that entire area and they're all good. I checked all of the resistor values too and they're fine.
 

bjf

Member
Looks good. Diode measurements match a good board. I attached pics of the other 3 spots that got hit.
 
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bjf

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bjf

Member
Yes, you're right, that is U1950 and it definitely looks like it got hit. I replaced it with a known-good chip. No change.
 
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bjf

Member
Yeah, everything looks good. It looks like it wasn't hit. I'm measuring 3.42V on the pin. When I measure on Pin 5 (PM_S0_PGOOD) I'm seeing a short pulse up to 3.4V every 5 seconds or so.
 

bjf

Member
Yes, it's also going up. It looks like it's hitting a normal voltage when it pulses, maybe slightly high. Somewhere around 1V, slightly higher or lower at times.
 

bjf

Member
Yes, it seems to be hitting about 0.6V on R1962.
It looks like it's hitting the correct voltage on Y1905 when it pulses. SYSCLK_CLK25M_X2 is hitting around 0.9V and SYSCLK_CLK25M_X1 is hitting around 1.3V (it stays at around 0.8V when not pulsing.)
 

dukefawks

Administrator
R1962 should spike at 3V, preferably use a scope, multimeter is too slow.
What is the voltage on Y1905?? Should not spike over 1.6V on both pins.
 

bjf

Member
Yes, R1962 is hitting around 3V.

Y1905:
Pin 1: SYSCLK_CLK25M_X2 is hitting around 0.9V
Pin2: SYSCLK_CLK25M_X1 is hitting around 1.3V (it stays at around 0.8V when not pulsing.)
 
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