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Hp laptop adapter fail

73's de Edd

Aug 21, 2015
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Sir pharaon . . . . .

there's short(beep) between the blue circle leds

The beep should have been on the internal LED leads of that optical isolator and what was its reading in millivolts on the meter.
The OI's other section is the dual junctions of a light detecting transistor junction . . .thus the reason for about twice of what I am expecting to hear that the LED is being.

I dont believe that you have ANY problem with that item.

Can you give us the numbering that 16 pin flat pack IC just above the central 10 Ω pwr film resistor.
I am sort of thinking of an LTA 301P. controller.

I HIGHLY suspicion that one of its internal totem pole driver transistors inside of it was blown to bits, as the original,( just being referenced), central 10 ohm resistor was blown up by the blown power FETS drain source directly shorting together and also sending their high voltage level up the 10 ohm unit to that driver section of that PWM controller IC.

I may have its reference schematic prepped tomorrow.

73's de Edd
 

pharaon

Oct 28, 2014
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i got clear picture for lenovo pa-1900-56lc adapter
i think it's the same circuit

GzStUCU.jpg
 
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pharaon

Oct 28, 2014
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is there any way i can test the LTA 803N to check if its working or not
 

davenn

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Sep 5, 2009
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is there any way i can test the LTA 803N to check if its working or not

I cannot find a datasheet, so I don't even know what the chip is, let alone how to test it
 

pharaon

Oct 28, 2014
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Found this in other website

Claim that LTA803N is a counterfeit of TEA1752 / TEA1753

Is that true
 

pharaon

Oct 28, 2014
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3970516700_1445630816.jpg

after the first burst the 15a 250v fuse were blown as well so i changed it with the resistor

now i tried to try the unit again with 60watt bulb

and the new fuse were burst again
so there must be shorted some where but i don't know where exactly
 
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davenn

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after the first burst the 15a 250v fuse were blown as well so i changed it with the resistor

that's a 3.15A fuse NOT 15A

now i tried to try the unit again with 60watt bulb

and the new fuse were burst again
so there must be shorted some where but i don't know where exactly


quite possibly the bridge rectifier --- appears to be on the heatsink on the top right of your latest pic
 

tedstruk

Jan 7, 2012
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If they are $7.00 on ebay....then save this for parts and buy a new one.
cause it looks like your just making it worse...
 

pharaon

Oct 28, 2014
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How to check if the lta803n got dc current or not
I mean to check if the problem from something else but it
 

davenn

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How to check if the lta803n got dc current or not

as I said before .... we don't have a datasheet so we don't even know what each pin does
without that info, it is unknown what voltages to expect on which pins
 
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