Acer Aspire 3680 Power Issue

[clayguthrie29]

hello all,

I'm working on a Acer Aspire 3680 laptop with a power issue. Plug it in, no lights, no power...nothing. Checked the charger and it tested fine ( 120 vac in, 42 vac out ). I've attempted to power on with and without battery. I've pretty much got it ruled down to a bad power board, but i wanted to double check my work.

Would i be accurate to assume that if the power board was outputting power, i would at least get a light?

Is the power light bypassing the motherboard or does it pass through it? And if it passes through it, it is possible i could have a bad motherboard. ( I would assume for troubleshooting purposes that the charge lights are bypassing the board. )

I'm pretty confident in my ruling, but would like some input from you guys. thanks in advance.

 

[rusty.nells]

42V/AC out? It should be about 18-20V/DC. Look on the brick for specs.

 

[NYJimbo]

42 vac out

Man,I hope you mean watts or something else.

 

[studiot]

Man,I hope you mean watts or something else.

Hear Hear


Clay,

This is a serious issue. As you are a serious tech and both the problems you have presented have had to do with laptop/power_supply issues do you require help with the electronics side of things? Not all techs will have come the hardware route and may be a bit at sea with it.

 

[clayguthrie29]

While electricity isn't my strong suit, I feel that i may be testing a bit differently than the standard. That's the normal read-out i get from my multimeter ( even on working devices ). And that is particularly why i came here to verify my work. I realize the output should be about 19.5 vac from the charger, but that is the solid, consistent reading i get from each and every unit i test. As i stated before, i may utilize a different testing method than yours though. Feel free to enlighten me on my weakness though. Thanks for the responses.

I'd just like to add that even after i tested this charger last night, i did go back and check my working dell charger ( because of exactly what you said ) and it tested the same reading. I very possibly could be using a different setting though.

 

[NYJimbo]

While electricity isn't my strong suit, I feel that i may be testing a bit differently than the standard. That's the normal read-out i get from my multimeter ( even on working devices ). And that is particularly why i came here to verify my work. I realize the output should be about 19.5 vac from the charger, but that is the solid, consistent reading i get from each and every unit i test. As i stated before, i may utilize a different testing method than yours though. Feel free to enlighten me on my weakness though. Thanks for the responses.

I'd just like to add that even after i tested this charger last night, i did go back and check my working dell charger ( because of exactly what you said ) and it tested the same reading. I very possibly could be using a different setting though.

If you are testing the tip/ring on the plug of a AC adapter (its not a "charger", I wish people would stop calling it that) and you see 42 volts where the AC adapter tells you it should be 19 then you are testing it wrong.

 

[studiot]

There are almost no latops that require an alternating (AC) supply from their mains adapter. The vast majority require DC, mostly in the range 12 to 22 volts.

A DC voltmeter will display zero when testing AC.

An AC voltmeter testing DC will give an unreliable reading depending upon the nature of the supply.
In particular a switching supply such as a laptop charger will actually be pulsed and require a suitable load. Just measuring with a meter alone will not provide such a load and the reading will be high.
Additionally you will need to divide by both the form factor and the RMS factor (neither of which you know) to get the DC equivalent.

A quick look at a 12 volt switch supply to hand reveals that off load it reads 16.7 volts on the DC range and 36 volts on the AC range.

You should be using the DC range of your voltmeter.

Have a look at post#15 of this thread I list various voltage measuring devices I habitually carry. There is one useful gadget for testing mains adapters there.

http://www.technibble.com/forums/showthread.php?t=7539&highlight=voltmeter


If there is call for a thread describing the use of voltmeters, start one and I will happily post my advice.

 

[NYJimbo]

You should be using the DC range of your voltmeter.
.

Aww, you couldnt wait a little longer for him to figure it out ..

 

[clayguthrie29]

I really truly appreciate that help. And for the records it is reading 19.38. So do we agree on my original issue?

 

[NYJimbo]

I really truly appreciate that help. And for the records it is reading 19.38. So do we agree on my original issue?

Well, your first post makes the assumption it's the power board. But if you look at that board it doesnt have much circuitry so it's not likely the charging circuits are there, but you would have to check further. Regardless, assuming its the power board is not a good idea as once the power leaves the power board and goes to the mobo it could be any number of circuits dead that would give you no lights. You might want to test for continuity on the power board if you havent already and look for fuses/links on the mobo near the powerboard connector to the mobo.