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L-CSteve
06-19-2010, 04:28 PM
Hey Guys,

Just recieved a Toshiba L300-146 today, For a DC Jack Repair. Opened the laptop up with batt and ac dissconected.

Sorted the dc jack out, However the motherboard does nothing, No fans work, No Beeps, No led lights light up at the front, it like the mobo is dead.

Any suggestions on a workaround, or know any companys that can repair the mobo itself.

I have used a multimeter to test voltages going into laptop and they are ok and reach the motherboard, Also looked around to see if mobo was shorted but carnt find anything.

vdub12
06-19-2010, 04:36 PM
Hey Guys,

Just recieved a Toshiba L300-146 today, For a DC Jack Repair. Opened the laptop up with batt and ac dissconected.

Sorted the dc jack out, However the motherboard does nothing, No fans work, No Beeps, No led lights light up at the front, it like the mobo is dead.

Any suggestions on a workaround, or know any companys that can repair the mobo itself.

I have used a multimeter to test voltages going into laptop and they are ok and reach the motherboard, Also looked around to see if mobo was shorted but carnt find anything.

There was a thread about a week ago that talked about some notebooks have a fuse.

L-CSteve
06-19-2010, 05:28 PM
I have stipped the laptop down to the mobo, I have found the 2 fuses, 1 for power & 1 for battery, i have done the following at the web address http://www.laptopsockets.co.uk/fuses-links.htm and i get a reading of 01.1 ohms for both.

Im taking the fuses are not blown, im confused now

Martyn
06-19-2010, 05:41 PM
I can't see if they are plugged in or soldered. If they are plugged in, test them off the motherboard in case there is something else you are reading through.

Larry Sabo
06-19-2010, 05:52 PM
Fuses normally (at least all those I have encountered) have a resistance much less than 1.0 ohms. Try re-measuring with the DVM leads reversed to see if what you are reading is the forward resistance of a diode. If the reversed resistance is much higher, it indicates an open fuse.

L-CSteve
06-19-2010, 05:54 PM
These fuses are soldered to the mobo, If the fuses are working would i get a 0.0 reading. or is the original reading ok

Still get a reading of 01.1, if i change the dvm leads reversed i get between 4.** - 6.** ohms

Martyn
06-19-2010, 06:21 PM
These fuses are soldered to the mobo, If the fuses are working would i get a 0.0 reading. or is the original reading ok

Still get a reading of 01.1, if i change the dvm leads reversed i get between 4.** - 6.** ohms


Touch the leads together just to check the DVM is zero'd ok

L-CSteve
06-19-2010, 06:44 PM
when the dvm leads not touching i get a reading of: 1 .

But when there touching i get 00.7

Larry Sabo
06-19-2010, 09:18 PM
When the leads are not touching each other nor anything else, the DVM should read open circuit, i.e., infinite ohms. Maybe the 1 you mention indicates "Out of range," but that's a strange DVM to read that way. When they are shorted together, the DVM is reading the resistance of the leads and connection where you are holding the probes to each other, plus any internal error, so the earlier reading of 1.1 indicates the resistance of the fuse is about 0.4 ohms. However, the reverse resistance of 4.** to 6.** ohms (3.** - 5.** after subtracting lead resistance) is rather high and suspicious. I don't have a laptop motherboard with fuses that I can test for comparison but if you do, make a few tests and decide if the 3-5 ohms is common.

L-CSteve
06-19-2010, 10:42 PM
Maybe my Tester is starting to fail, i have a tool tech dt830b, However im thinking about sending this laptop of to a company who can repair this fault in regards to either a fuse or diode etc etc.

Does anyone know of any good companys within the UK who repair motherboard faults with a good sucess rate.

Cheers, thanks for your support guys

vdub12
06-20-2010, 01:18 AM
I think there something wrong with your meter because unless your testing it under water you should get an open connection if there not touching.

Some fuses might get a little resistance but for the most part it should be very low. You can try testing them with a probe and see if they light the probe up.

hyfidel
06-20-2010, 07:09 AM
Wouldn't it be easier to just put the meter on continuity mode and listen for the beep?