Regulator STR-58041 will this selfdistruct if

[Jim Lazzaro]

On TV Orion model S21 (which does not start) the power supply
regulator STR-58041 has 329 volts on pin 3. The schematic shows it
should have 280 volts.
Since I haven't been able to solve this start up failure, I am now
wondering if:
1) the 329 volts apllied to it is sensed by the regulator as out of
specs and therefore it does not turn itself on.
or 2) the 329 volts is just higher because there is no current flowing
due to the regulator being defenitely faulty.
Note- all other checks have been done and also there are no shorts
found, resistors have been checked etc., new caps installed.
Please pass on your thoughts on this.
Thanking you
Jim

 

[Franc Zabkar]

On 28 Jul 2004 19:56:11 -0700, Jim_Lazzaro@hotmail.com (Jim Lazzaro)
put finger to keyboard and composed:

On TV Orion model S21 (which does not start) the power supply
regulator STR-58041 has 329 volts on pin 3. The schematic shows it
should have 280 volts.
Since I haven't been able to solve this start up failure, I am now
wondering if:
1) the 329 volts apllied to it is sensed by the regulator as out of
specs and therefore it does not turn itself on.

Pin 3 is the collector of the chopper transistor and is connected to
the rectified 240VAC via the primary winding of the switching
transformer. As such it should measure 240 x 1.414 = 340VDC if the PSU
is in the no-start state.

or 2) the 329 volts is just higher because there is no current flowing
due to the regulator being defenitely faulty.
Note- all other checks have been done and also there are no shorts
found, resistors have been checked etc., new caps installed.
Please pass on your thoughts on this.
Thanking you
Jim

- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

 

[mo]

Franc Zabkar <fzabkar@optussnet.com.au> wrote in message news:<mhchg01svfbmfeuubjgiv1tgr4v2pettu5@4ax.com>...

On 28 Jul 2004 19:56:11 -0700, Jim_Lazzaro@hotmail.com (Jim Lazzaro)
put finger to keyboard and composed:

Filed this reply in the wrong pigeon hole,but here goes anyway.
It is possible that there are 2 resistors of about 120 kOhm in series
from large capacitor to where you are supposed to find that 0.4 Volts
on your ic.
Isolate one end of resistors and measure resistance.
Good luck.