Acer AL718: It Goes On And Off

[Davi.p]

Re: Acer AL718: It Goes On And Off

"The Mosfet 27G11 gives (Cold)fluctuating readings on one the right leg .625 on the left
leg noting at all"

I don't know how you've made the readings..
lets imagine the item, the label on the front, heatsink in the back, legs under.. leg to the left is most of the times g, then d, then s to the right, report the radings in each combination like (+ is the red probe):
+ - + - + -
G-D G-S D-S
- + - + - +
G-D G-S D-S

Bye..

[nick2012]

Re: Acer AL718: It Goes On And Off

It has only 3 legs ?

[Davi.p]

Re: Acer AL718: It Goes On And Off

yes like all mosfets.. i repeat but you re-read my past message, there are 2 bigger heatsinks, the one smaller of them has the mosfet connected..

[nick2012]

Re: Acer AL718: It Goes On And Off

Okay I' had the Mosfet taken out and maesurd G=open D&G=close in beeb mode.
In Diode mode G+=0,D-,G+=.28 and G-=0,D+=0,G-0,So only the center and
Right leg gives a' reading,hope thats understandeble else I have to make a' photo
perhaps.

[selldoor]

Re: Acer AL718: It Goes On And Off

I dont follow it here is an easy way to present results

Mosfets

If you have a manual range multimeter, set it to 200 ohms (two hundred). This is for 3 pin ICs only. You can test a mosfet (Q, IC designation) "in circuit" by (power off and unplugged)

a) black on pin 1- red on pin 2 - record ohms
b) black on pin 1- red on pin 3 - record ohms
c) black on pin 2- red on pin 3 - record ohms

If any reading is less than 30 ohms you might have shorted mosfet. Remove from circuit and repeat the tests to verify.


This test is from retiredcaps 2 seconds to black - there are a lot of useful
tests in there the next one tells how to test the 8 leg mosfets.

see here
https://www.badcaps.net/forum/showthread.php?t=10419
start at post 19

[nick2012]

Re: Acer AL718: It Goes On And Off

Okay I'll get zero on all legs in Ohms mode,so its defect for sure,I have already removed it
from circuit,and still read 0 ohms on all legs.

so i got to search for a replacment part.

[nick2012]

Re: Acer AL718: It Goes On And Off

Found a' other from the outher board with readings,
A.Black
B.24 Ohm
C.36.5 Ohm

A.13.2 Ohm
B.Black
C.13.2 Ohm

And has a marking on it like ->|o|<- .
name&type.
LT6207
SBF1045CT

Maby usseble as replacment ?

[selldoor]

Re: Acer AL718: It Goes On And Off

I am still not sure you are understanding the instructions.
No answer should be Black and you should only have three readings
not 2 sets and if any reading is less than 30 ohms it is likely to be bad.

So
a) black probe on pin 1- red probe on pin 2 - how many ohms?
b) black probe on pin 1- red probe on pin 3 - how many ohms?
c) black probe on pin 2- red probe on pin 3 - how many ohms?

I have to go out now for a couple of hours.

[nick2012]

Re: Acer AL718: It Goes On And Off

then it's defect ,i'll get no readings ,on none of the legs !,its dead for sure,
the other one hoever gives good readings.
Will look for replacement tomorow at the local store.

[Davi.p]

Re: Acer AL718: It Goes On And Off

nick i've understood you, the symbol ->.<- means it is a double diode and is not suitable..
report the label on the mosfet so we can help to find a replacement. Then measure all the 3 legs chip on the other heatsink like this:
in diode mode
red on central pin, black on outer pins > must read infinite
invert probes > must read something like 0.150 - 0.600 (sorry i don't know common values for shottkies), in any way if shows 0.00 is shorted. Test also in ohm the big resistor connected to the S leg of mosfet and each pin with each other of the 8 pin chip on the back..

[nick2012]

Re: Acer AL718: It Goes On And Off

the ID of the Mosfet is 27G11 ,939030 could not find anything on internet of this type.
the 8 leg chip on the backside will I' later check,but i'am litle baffeld on how to do it,
sounds verry complicated.

[Davi.p]

Re: Acer AL718: It Goes On And Off

i don't even find anything with that label, you have to take one 600v 10A N channel minimum, 8 leg chip it checks like i said, in ohm low scale measure from each pin to each other and write down results...

[nick2012]

Re: Acer AL718: It Goes On And Off

It's whay to complicated for me now,and trow everyting in the trashcan,thanks for
your time and info.

[selldoor]

Re: Acer AL718: It Goes On And Off

"It's way to complicated for me now,and throw everything in the trashcan,thanks for
your time and info. "

Sorry to hear that

What about plan B or was it plan A.
I felt that was a good price and good idea but thought Davi-p had hands on experience of faulty bulbs.

As the main board was not connected when you "shorted" it should still be ok.

its way to dificult for me,
As alternite I'found that it may be beter to buy a' replacment board at:

http://nl.aliexpress.com/item/ViewSo...944393283.html

[Davi.p]

Re: Acer AL718: It Goes On And Off

Yes, what about a plan B? Since your lamps are good with much probabilities.. you can inspect the lamp ends and if you don't damage them by a error after that you order a new psu board.. (think to the green..)