VZVZ2016-04-24 19:33:16
Do it yourself
VZVZ, 2016-04-24 19:33:16

After the repair, the laptop power supply emits quiet, even clicks and crackles, and hums very quietly. What about him?

ASUS original power supply, 19 V, about 6 A.
Today (by the way, only 4 months have passed) there were problems with the output plug (the contact was lost), I decided to disassemble and replace the output cable.
There were problems with disassembling the case, it was very tightly welded, and my skills were dulled from time to time.
In general, the disassembly was not the most accurate, it was not without a hammer and picking everything that came to hand.
After that, I unsoldered the cable and replaced it, I also soldered the screen casing (I just wanted to see what's inside), the casing has 2 solders.
I decided to try to connect it to an outlet with an open case - and then I heard these very cods.
Cods appear WITHOUT load, somewhere in 1-2 seconds after being plugged into the outlet (and disappear in the same way).
Their frequency is about the same as that of the human heart. Quiet.
When I closed the case, it became almost inaudible, only if you bring it to your ear.
Features: The
PSU is zeroed (instead of grounding), I tried to remove the zeroing and return it - it does not affect.
There are a lot of chokes in the PSU.
1) What could I short-circuit and how? Cable and its soldering - 100% no. About 2 rations of the casing, I also do not see anything.
I sin on the transformer, maybe he? But why then such a low frequency of crackling?
2) How can you help yourself determine where it's cracking? What can be soldered for this?
3) Can such a PSU be harmful, especially for a laptop?
There is no oscilloscope, the battery seems to be charging, nothing is buggy in the computer (touchpad, etc.), BUT according to the multimeter, the output voltage jumps + - 10 -20 mV.
UPD: now (closed case) I also hear a quiet buzz if I put it to my ear. Already with a high frequency, well, how the transformers are buzzing. Should that transformer hum?

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2 answer(s)
Alexander Volkov, 2016-04-25

The cores and windings of chokes and transformers can make sounds during operation, this is normal, but it indicates that you knocked down the fixation of the windings on the cores during disassembly.

iv_k, 2016-04-25

it inductors click. they are usually filled with something like hot melt or compound. and it looks like they left it that way.

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