[TV] Re: Magnovox PTV843 dead LED on

[John Peters <peters@xxxxxxxx>]

Is this the one with the 3 optocouplers at the rear of the chassis? The 
large one fails all the time. I have changed about 15 of these.
> anyone have the schematic to the large signal panel. I am chasing my 
> tail on this one....
>
> -----
> Mike
>
>
> Mike wrote:
>   
>> just got back from looking at the set. the main power supply will not 
>> start, however it is getting the startup signal from the signal module. 
>> all standby voltages are present where they should be, 12v present at 
>> proper points on the cold side controller IC. I found one bad capacitor, 
>> it was bubbled up, 470uf, 25v off near the shutdown IC. replaced this. 
>> checked both the HOT and HVOT, they are fine. tested all diodes in the 
>> circuits and they are also fine. no signs of burned resistors, all SMD 
>> transistors test A-OK.
>>
>> I replaced the cold and hot side controller ICs with ones i found on 
>> another board i had laying around, but it still wont startup, and theres 
>> no telling if those ICs were any good either so i might have to just get 
>> new ones and hope for the best. ESR test of all the caps indicate they 
>> are all A-OK.
>>
>> any ideas? thanks.
>>
>> -----
>> Mike
>>
>>
>>
>> Mike wrote:
>>   
>>     
>>> buddy of mine called me up about one of these, no picture, no sound, LED 
>>> only. i think ive seen this chassis before, not sure. is it similar to 
>>> the PTV800/PTV810?
>>>
>>> -----
>>> Mike
>>>
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-- 
John Peters
Peters` Electronics
Port Lavaca,Texas 77979
361-552-4398

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