[TechAssist] FIXED: Sony KV-32FS12 no 5V standby (dead)


Sony Model KV-32FS12
Symptom:  Dead set, no 5 volt standby supply.
Fix:  C639 (22uf x 50vdc) primary side of standby by power supply.
Explaination:  High input to IC002 causing internal shutdown to kill 5v=
 output.

Thanks to everyone that replied, and special thanks to those that 
mentioned the internal shutdown in IC002. The suggested parts where
not the problem, but this info got me in the right direction.
I had ignored the fact that the input to IC002 was high, assuming it 
was only high because it was not being loaded. I thought I had verifed this
while testing, because when I jumpered from pin 4 to pin 5 with a resistor
both the input and output voltages for IC002 were exactly correct. 
So once I started to look for a reason for the 7.5v to be high. I found a=
 defective C639.
All is well now. 

Thanks,
****************************************
Lynn C. Hedspeth, CET NC-407
Hedspeth Enterprises Inc.
3521 E. Hwy 27
Lincolnton, NC  28092-7659
704-735-3532
413-828-0216 (fax)
HedTV@xxxxxxxxxxxxx
***************************************

*********** BEGIN FORWARDED MESSAGE ***********
>
>Sony KV-32FS12
>
>Set will not turn on because it has no 5v standby. IC002 is the standby
>regulator IC and it has a good supply to pin 4 (input), but 0v on pin 5=3D
> (output).
>I replaced IC002 but still no standby 5V.
>
>I can input 5v at pin 5 and the set will play. I have even jumpered=
 from=3D
> pin 4 to
>pin 5 with a 120ohm resistor to limit the current and check for=
 loading,=3D
> and it
>still plays fine.
>
>Short of deciding that the new IC002 is defective, does anyone have any=3D
> other
>suggestions. (I ordered the OEM Sony part number 875966329)
>
>Just for info, the voltages are exactly correct with the 120ohm resistor=
 in=3D
> place.
>7.5v pin 4
>5v pin 5.
>
>There is no 5v reset on pin 2 of IC002 (0V), but neither the micro or=
 the=3D
> couple of other
>components hooked to pin 2 is loading it down. And since this voltage=
 is=3D
> supplied internally
>by the IC, I am assuming this just a secondary issue related to the=
 missing=3D
> standby 5v.
>

*********** END FORWARDED MESSAGE ***********


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