REQ: Emerson 19" tv TC1993 no power

J

Jan

Guest
Need info on low voltage regulator str 30130.

Any advice appreciated.
TIA
Jan
 
Here...

http://www.nteinc.com/specs/1700to1799/NTE1776.html

kip
--
"Watch the return E-Mail addy its false"
"Jan" <jan@pan.co> wrote in message
news:f9p930lpnjpmj6k7tpcqfg8kan7e2opo5k@4ax.com...
Need info on low voltage regulator str 30130.

Any advice appreciated.
TIA
Jan
Click to expand...
 
Jan:
If it is not putting out regulated B+ @ 130 V DC it is most likely
faulty..... obviously the other supporting circuitry can cause a B+ faults
like shorted loads (always look for a bad HOT), bad pre-regulator diodes and
filter, faulty base drive/reference, open resistors, etc. The STR 30130 is
usually a fairly reliable unit as long as it is heat sinked well and the
solder connections aren't cracked or dry.... or there isn't a fault before
or after the chip.
Pin 1 Common
Pin 2 Base
Pin 3 Input
Pin 4 Output
Pin 5 n/c

Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Jan" <jan@pan.co> wrote in message
news:f9p930lpnjpmj6k7tpcqfg8kan7e2opo5k@4ax.com...
Need info on low voltage regulator str 30130.

Any advice appreciated.
TIA
Jan
Click to expand...
 
On Thu, 19 Feb 2004 10:26:01 -0800, "Sofie" <sofie@olypen.com> wrote:

Jan:
If it is not putting out regulated B+ @ 130 V DC it is most likely
faulty..... obviously the other supporting circuitry can cause a B+ faults
like shorted loads (always look for a bad HOT), bad pre-regulator diodes and
filter, faulty base drive/reference, open resistors, etc. The STR 30130 is
usually a fairly reliable unit as long as it is heat sinked well and the
solder connections aren't cracked or dry.... or there isn't a fault before
or after the chip.
Pin 1 Common
Pin 2 Base
Pin 3 Input
Pin 4 Output
Pin 5 n/c

Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Thank you for your input.
Click to expand...

I am first year EE student and appreciate your efforts.

I have no voltage out of the regulator.

There is a relay that is not energizing and I assume that;s because
there is no high voltage.

A viscious circle.

How to continue?

No schematic .

Thanks again

Jan
 
Jan:
Slow down a little.... there is a lot of successful troubleshooting and
repairing that can be done without a schematic. Take some time and trace
the circuitry with your eyes..... checking different components with your
DMM.
There is no high voltage because there is no regulated 130 v B+ coming out
of the chip and there are a lot of reasons that there is no voltage coming
out of the chip....... is there "raw" B+ at pin 3 ? (~ 150 V) of the
regulator chip as referenced to pin 1? Did you check for shorted parts and
components in the circuitry after the chip? (see my previous reply post with
suggestions) Do you have a replacement chip that you can install?
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
-----------------------------------


"Jan" <jan@pan.co> wrote in message
news:soee3019aucmaifogs0903rjko2ulrccm5@4ax.com...
On Thu, 19 Feb 2004 10:26:01 -0800, "Sofie" <sofie@olypen.com> wrote:

Jan:
If it is not putting out regulated B+ @ 130 V DC it is most likely
faulty..... obviously the other supporting circuitry can cause a B+
faults
like shorted loads (always look for a bad HOT), bad pre-regulator diodes
and
filter, faulty base drive/reference, open resistors, etc. The STR 30130
is
usually a fairly reliable unit as long as it is heat sinked well and the
solder connections aren't cracked or dry.... or there isn't a fault
before
or after the chip.
Pin 1 Common
Pin 2 Base
Pin 3 Input
Pin 4 Output
Pin 5 n/c

Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Thank you for your input.

I am first year EE student and appreciate your efforts.

I have no voltage out of the regulator.

There is a relay that is not energizing and I assume that;s because
there is no high voltage.

A viscious circle.

How to continue?

No schematic .

Thanks again

Jan
Click to expand...
 
On Sat, 21 Feb 2004 07:30:47 -0800, "Sofie" <sofie@olypen.com> wrote:

Jan:
Slow down a little.... there is a lot of successful troubleshooting and
repairing that can be done without a schematic. Take some time and trace
the circuitry with your eyes..... checking different components with your
DMM.
There is no high voltage because there is no regulated 130 v B+ coming out
of the chip and there are a lot of reasons that there is no voltage coming
out of the chip....... is there "raw" B+ at pin 3 ? (~ 150 V) of the
regulator chip as referenced to pin 1? Did you check for shorted parts and
components in the circuitry after the chip? (see my previous reply post with
suggestions) Do you have a replacement chip that you can install?
Click to expand...
Thanks for the advice .

I have been doing some eyeballing with mag glass also and cannot see
any open traces etc.

Volt reg chip has 0 volts on pin 3.

Volt reg chip pin 3 goes to the relay contact through a resistor that
is not open.

I also have obtained a capacitor esr tester and I am in the process of
testing some caps in the power areas.

Hot appears to test ok out of circuit using meter diode testing bce;
but I have no reference to compare. base collector 520 ohms and base
emitter 49 ohms; I believe this is because of diode internal.

I will be obtaining an HOT and volt reg chip on Monday and will keep
you informed of my progress.

Thanks Jan.
 
Jan:
You might check for a 3 terminal regulator chip.... maybe a 7805 or
7806.... on the board that supplies standby voltage to the syscom chip....
sometimes near and around the VCR circuitry.... if there is no standby B+
going to the syscom chip then it won't energize the relay when the power
button is pressed.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
--------------------------


"Jan" <jan@pan.co> wrote in message
news:2fnf30dp6pc3o87kibtgd07oq9uneukpe2@4ax.com...
On Sat, 21 Feb 2004 07:30:47 -0800, "Sofie" <sofie@olypen.com> wrote:

Jan:
Slow down a little.... there is a lot of successful troubleshooting and
repairing that can be done without a schematic. Take some time and
trace
the circuitry with your eyes..... checking different components with
your
DMM.
There is no high voltage because there is no regulated 130 v B+ coming
out
of the chip and there are a lot of reasons that there is no voltage
coming
out of the chip....... is there "raw" B+ at pin 3 ? (~ 150 V) of the
regulator chip as referenced to pin 1? Did you check for shorted parts
and
components in the circuitry after the chip? (see my previous reply post
with
suggestions) Do you have a replacement chip that you can install?

Thanks for the advice .

I have been doing some eyeballing with mag glass also and cannot see
any open traces etc.

Volt reg chip has 0 volts on pin 3.

Volt reg chip pin 3 goes to the relay contact through a resistor that
is not open.

I also have obtained a capacitor esr tester and I am in the process of
testing some caps in the power areas.

Hot appears to test ok out of circuit using meter diode testing bce;
but I have no reference to compare. base collector 520 ohms and base
emitter 49 ohms; I believe this is because of diode internal.

I will be obtaining an HOT and volt reg chip on Monday and will keep
you informed of my progress.

Thanks Jan.
Click to expand...
 
Jan,
One end of the relay coil connects to the standby power supply, the
other end to the relay switching transistor. The standby supply powers
the microprocessor, relay switching transistor and relay coil. When
the power button is pressed the microprocessor turns on the relay
switching transistor supplying 5 volts through a resistor to the base.
The relay closes and provides input to the STR30130. Look to see is
the base of the relay switching transistor getting its forward bias
when the power button is pressed.
Gordon Gaskell AAS
Home Electronics of Havre de Grace, Maryland
 
On 21 Feb 2004 19:29:03 -0800, gordongaskill@netzero.net (Gordon
Gaskell) wrote:

Jan,
One end of the relay coil connects to the standby power supply, the
other end to the relay switching transistor. The standby supply powers
the microprocessor, relay switching transistor and relay coil. When
the power button is pressed the microprocessor turns on the relay
switching transistor supplying 5 volts through a resistor to the base.
The relay closes and provides input to the STR30130. Look to see is
the base of the relay switching transistor getting its forward bias
when the power button is pressed.
Gordon Gaskell AAS
Home Electronics of Havre de Grace, Maryland
Click to expand...
Thanks for the info Gordon.

I checked the voltage at the base of the relay switch transistor.

This was measured as .5 volts.

I also replaced the HOT and the volt regulator on spec.

I believe the relay is not picking up to supply voltage to regulator.

Cannot trace where the relay is fed from.

Thanks

Jan
 
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