meantomatoes
Member
Last Activity: 04-14-2025, 10:16 PM
Joined: 06-03-2018
Location: Florida
-
Turns out I had the CPU 90° the wrong way. The corner arrow is not obvious on this motherboard. -
Update, found a Hz mode on my multimeter, the RTC crystal near the CPU and the one near the I/O header pins both read almost exactly 60 Hz. Puzzling.Leave a comment:
-
ASUS Prime X470-Pro No Power on
Hi all,
Building my second PC with parts from Facebook, lo and behold the motherboard doesn't turn on. I initially thought 5VSB was missing but realized it's not because the RGBs work fine as soon as it's powered and actively change colors, but there's no response by shorting PWR_SW. Voltage at PWR_SW is ~3.3V. By shorting PSU power pins, components turn on but board does not POST. Clearly, there is an issue with the power circuit.
Does anyone have a boardview for this board? I've fixed MacBook boards but not PC boards. I don't have an oscilloscope to measure the RTC.... -
Re: A1502 Macbook Pro 13" liquid damaged 820-3476, orange light no power
Sorry for the slight necro but I wanted to update you. I removed R8190 first and found the short on PP3v3sus_en, which could only be U8020. SLP_SUS is now 3.3v, yaaay. The other rails connecting to U8020 are fine. I ordered a donor on aliexpress so hopefully it will have a working U8020
I'll post a final update once it arrives.
Leave a comment:
-
Re: A1502 Macbook Pro 13" liquid damaged 820-3476, orange light no power
Wait--after checking S5_PWRGD again it's actually 3.42 as normal. Not sure what I was measuring before...
So, short on SLP_SUS is either CPU, R1464, Q5490, or on P3V3SUS_EN etc. I don't see where it would be tied to SMC?Leave a comment:
-
Re: A1502 Macbook Pro 13" liquid damaged 820-3476, orange light no power
Okay, thanks. It actually looks like some of the underfill stuff got under the balls. Will probably try cleaning and reballing but I need to get the stencil. Will report back
After removing smc SLP_SUS short should go away right?...Last edited by meantomatoes; 10-07-2020, 02:53 PM.Leave a comment:
-
Re: A1502 Macbook Pro 13" liquid damaged 820-3476, orange light no power
Hi piernov, thanks for replying
So should I try replacing or maybe reflowing smc? I don't have a donor board
Also thanks for the software in your sig! I've been using phoneboard
...
Leave a comment:
-
Re: A1502 Macbook Pro 13" liquid damaged 820-3476, orange light no power
Not sure who came up with that rule but here's my second edit:
I think PM_PCH_PWROK is 0 because ALL_SYS_PWRGD is 0. Not sure why. Not short. So it's probably not an issue with U1950 as is common with this model.Leave a comment:
-
A1502 Macbook Pro 13" liquid damaged 820-3476, orange light no power
I'm new to board repair so bear with me. Just my luck that this is my first.
This board likely had work done before. It was probably ultrasonic'd because it's pretty clean. The SMC had its underfill removed so someone probably reflowed or replaced (doubt) it. Pictured: Near the SMC the traces of Q5490 for pins 4 (PPDCIN_G3H_ISOL) and 2 (PP_SLP_SUS_L) are somewhat exposed.
It's stuck in S5 and missing PM_SLP_SUS_L (shorted) although I don't think that exposed trace is the problem, may have been the last person being lazy for a reading? Anyway, is this a dead CPU? As I'm...Last edited by meantomatoes; 10-06-2020, 12:33 AM. -
Re: Samsung UN40EH5300F No Power
happy to report that with the new diode all is well! TV works perfectly! thanks everyone for helping...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
okay, ordered SB360, will keep everyone posted. what do you think of those other two diodes with fluctuating voltages? they have a different P/N unfortunately. they're on a different transformer leg than DM851C. and the transformer clicking?...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
SR306 with 342Y under that. so it's likely the diode that's the problem and not that IC or transformer making the clicking sound?...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
shows 00.7 ohms in both directions. on diode mode, it shows 001 shorted together, and 1 not shorted...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
sorry for the bad quality...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
DM851C that i pulled from the cold side to test it. that shouldn't affect the IC should it? i'm not sure which pin is which, there's a little arrow on one of the pins, that one is showing 3V. the one to the left of it is showing 0 and the leftmost is 304V AC, except it drops and quickly regains with a new clicking noise at or near the transformer. is this because of the removed diode? the pin across from the leftmost and the adjacent one show 0. the next adjacent one actually jumps up to ~57V with the click and slowly falls down. the rightmost...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
should i put the diode back on before testing?
seems wasteful to me...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
same reading...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
DM851C shows 001, DM852C and DM853C show 328, and DM855C-DM858C show ~448.
for the IC, i assume you mean the number printed on it and not the voltage or anything? it's 3S111, SK391, 267(and maybe a 1 or I or L)...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
DM851C has no resistance in either direction, DM852C and DM853C have something wonky where they slowly increase slower and slower in the correct orientation to like 8k ohms (is that right? the dial is on 20k and it's showing ~8.00) and then slowly decrease with the opposite direction. DM855C-DM858C have ~16k ohms and then ~100k the opposite way.
IC? where would that be?...Leave a comment:
-
Re: Samsung UN40EH5300F No Power
yup, 170 volts not fluctuating...Leave a comment:
No activity results to display
Leave a comment: