Well, here's where I am:
1: Appears that the feed to the transformer feeding the 5 volt supply 
area is fed by a switching area possibly. There are 3 components there 
that I have not been able to find any info on. I f I can't find both 
info and a source (USA), I don't think it's worth while pursuing any 
further. Here are the 3 components:
LAF0001, 8 PIN DIP
AUK647, T0-220 case
CC705, EL817, 4 PIN DIP

If anyone has some info, thanks.

If I abandon the project, I would consider shipping it to someone in the 
USA for say $15 to cover packing and shipping USPS priority with 
tracking. Again it's a 20" LG LCD monitor. Dead, but looks good 
otherwise.  My other option would be take it to our local electronic 
recycle.

Thanks again.

Tony Vandiver wrote:
> Substituting the supply is a good idea.  Also, the list may have 
> stripped your attachments.
>
> Tony
>
>
> Carl Denk wrote:
>   
>> Here's photos.
>> There is a shunt regulator there, it's a KIA431A, TO-92 case rated to 
>> 100 ma. The PCB is a Lien Chang AIP0157. I should be able to make a 
>> rough schematic of major components, but thought I would get this out 
>> quickly. The 5 volt comes off the transformer as 1 winding. If in fact 
>> this 5 volt supply is rated at 100ma, then maybe it's OK, and the issue 
>> is downstream. I could try powering it from a separate 5 VDC supply by 
>> itself through a 100ma fuse.
>>
>> Thanks for the help.
>>
>> Tony Vandiver wrote:
>>   
>>     
>>> Are you sure that the 5V supply is a switching supply and not a linear 
>>> regulator TO-220 using the 12V as a source?  If it is a linear 
>>> regulator, 1/2A gives you 3.5W in the regulator which is over the limit 
>>> for TO-220 packages unless it's got an incredible heat sink.  I don't 
>>> know the monitor, but 500mA at 5V sounds like a lot for lcd logic level 
>>> stuff.  Then again, I know someone who makes a living replacing LG 
>>> supplies in televisions so I'd lean toward the supply being bad too.  
>>> Can you post a few pics of the power supply?  I couldn't really follow 
>>> the parts description.
>>>
>>> Tony
>>>
>>>
>>> Carl Denk wrote:
>>>   
>>>     
>>>       
>>>> Disconnected cable from power supply board to video board, and the 5 
>>>> volt supply measured at 5 volts. Used a 20 ohm resistor to create a 1/4 
>>>> amp load, still had 5 volts, changed to 10 ohm resistor for 1/2 amp 
>>>> load, and the 5 volt was back to a couple of tenths volts. I'm assuming 
>>>> that some regulator chip is shutting down due to over current, but am at 
>>>> a loss where to go from here.
>>>>
>>>> Some of the components are:
>>>> LG monitor model LT953LS
>>>> LG power supply board   E74MQ363049011235
>>>>     Transformer   LITAI   PT-007921, TF-2820, 2650C0167, appears to be 
>>>> an OEM custom  **
>>>>     Power Mosfet    (2) 4511GD  PCB is heat discolored slightly in this 
>>>> area, 8 PIN dIP
>>>>     Voltage regulator ??  AUK647, T0-220 **
>>>>     ??      BRF1015CCT, LTGTDIP, T0-220 **
>>>> LG video board   75E04862
>>>>     1.8 volt regulator for video chip, AZ1086S-1.8EI
>>>>   
>>>>     
>>>>       
>>>>         
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist