Lg 50pj550 no STBY light

[dzyk2000]

Re: Lg 50pj550 no STBY light

Well ,we need to get the other Voltage reading correctly first because you are report something that is impossible, I.E. 390VDC when no AC is present on the bridge. I do NOT want want to be chasing ghost due to wrong information/Data.

i have two multimeters, i know is imposible but is corect read 327 v dc.
in p813 socket i have 0v on all pins.

[dzyk2000]

Re: Lg 50pj550 no STBY light

Please upload the training manual.

here is manual

[budm]

Re: Lg 50pj550 no STBY light

Well ,we need to get the other Voltage reading correctly first because you are report something that is impossible, I.E. 390VDC when no AC is present on the bridge. I do NOT want want to be chasing ghost due to wrong information/Data.

[dzyk2000]

Re: Lg 50pj550 no STBY light

ok, what voltage should i have in stby and where, because i have no voltage than the above mentioned

[budm]

Re: Lg 50pj550 no STBY light

q352 and q356 are not powered by t301?

5.1V switched supply as I already indicated.
From your training manual:
When RL_ON arrives, the run voltage +5V source becomes active and is sent to the Main Board via P813 (5.24V at pin 5, 6 and 7)

[budm]

Re: Lg 50pj550 no STBY light

Please upload the training manual.

[budm]

Re: Lg 50pj550 no STBY light

q352 and q356 are not powered by t301?

17V switched power supply as I already indicated.
Your training manual:
'The RL-ON command also turns on the 17V (Audio B+ 16.79V) which is also sent to the Main Board.'

[budm]

Re: Lg 50pj550 no STBY light

yes

So no way you can have 390VDC as you reported then, without AC to the bridge.

[budm]

Re: Lg 50pj550 no STBY light

q352 and q356 are not powered by t301?

They are on the cold side and turned on when TV is turned on, so there will be no switched 5.1V or switched 17V until the TV is turned, those two Voltages will not be present in standby mode.

[dzyk2000]

Re: Lg 50pj550 no STBY light

RL_ON is 0V, correct?

yes

[budm]

Re: Lg 50pj550 no STBY light

RL_ON is 0V, correct?

[dzyk2000]

Re: Lg 50pj550 no STBY light

"Fuse F302 160V" But you have 327VDC, right?

yes

[dzyk2000]

Re: Lg 50pj550 no STBY light

"i dont understand why no have 5v (3.49v)" I do not understand the (3.49V). What is the 3.49V reading?
The 5.1V (switched Q352) and the 17V (switched Q356) are switched power supplies.

q352 and q356 are not powered by t301?

[budm]

Re: Lg 50pj550 no STBY light

"Fuse F302 160V" But you have 327VDC, right?

[budm]

Re: Lg 50pj550 no STBY light

If there is no AC feeding the bridge D101 then there is no way you can have that 390VDC on the main cap.

[dzyk2000]

Re: Lg 50pj550 no STBY light

"i dont understand why no have 5v (3.49v)" I do not understand the (3.49V). What is the 3.49V reading?
The 5.1V (switched Q352) and the 17V (switched Q356) are switched power supplies.

this is the text from training manual.

Power Suration AC Voltage is supplied to the SMPS Board at Connector SC101 from the AC Input assembly. Rectified by the Bridge rectifier D101 generates a primary B+. The Power factor circuit generates a Primary supply which can be read at Fuse F302 160V. This primary voltage is routed through T301 and routed to the Standby 5V supply. The STBY5V (standby) is B+ for the Controller chip on the back of the board (IC701) on the SMPS and output at P813 pins 13 and 14 then sent to the Main board for Microprocessor (IC1) operation (STBY 3.49V RUN 5.23V). When the Microprocessor (IC1) on the Main Board receives a “POWER ON“ Command from either the Power button or the Remote IR Signal, it outputs a high (2.43V) called RL_ON at Pin 15 of P813. This command causes the Relay Circuit to close both Relays RL101 and RL103 routing AC to the Bridge Rectifier D101 which then routes the primary voltage to the PFC circuit (Power Factor Controller) 390V which can be read measuring voltage at Fuses F302 (390V) and F801 (389V) from “Hot” Ground. AC Detection (AC Det) is generated on the SMPS, by rectifying a small sample of the A/C Line and routed to the Controller (IC701) where it outputs at P813 pin 16 (4.45V) and sent to P301 to the Main Board where it is sensed and monitored by the Main Microprocessor (IC1). If AC Det is missing the set will come on, but shut off in 10 seconds. When RL_ON arrives, the run voltage +5V source becomes active and is sent to the Main Board via P813 (5.24V at pin 5, 6 and 7). The (Error Det) from the SMPS Board to the Main Board can be measured at pin 8 of P813 (2.88V STBY and 4.93V RUN), but it is not used. The RL-ON command also turns on the 17V (Audio B+ 16.79V) which is also sent to the Main Board. The 17V Audio supply outputs to the Main board at P813 pins 1 and 2 and used for Audio processing and amplification. The next step is for the Microprocessor IC1 on the Main Board to output a high (3.27V) on M_ON Line to the SMPS at P813 Pin 17 which is sensed by the Controller IC701, turning on the M5V line and outputs at P811 pins 9 and 10 to the Y-SUS board. The Controller (IC701) also uses the M_ON line to turn on the VA and the VS supplies. (Note there is no VS On Command in this set). VS is output at P811 to the Y-SUS board P201. (VA pins 6 and 7 and VS pins 1 and 2). Note: The Va is fused on the Y-SUS then routed out P209 to the X-Board Left. VS is also routed out of the Y-SUS P206 pins 1 and 2 to the Z-SUS P2. AUTO GND Pin 18 of P813: This pin is grounded on the Main board. When it is grounded, the Controller (IC701) works in the normal mode, meaning it turns on the power supply via commands sent from the Main board. When AUTO GND is floated (opened), it pulls up and places the Controller (IC701) into the Auto mode. In this state, the Controller turns on the power supply in stages automatically. A load is necessary to perform a good test of the SMPS if the Main board is suspect

[dzyk2000]

Re: Lg 50pj550 no STBY light

Without having the board connected to other board and have Voltage on the main filter caps in the PFC circuit is that relay RL101 has to be closed, so you should verify that is no DC on the coil (measure right across the coil) of RL101. If the coil Voltage is not present then it mans the contact is stuck closed. RL103 is used for bypassing the NTC when PS-ON is present.
What DC V do you have between C377?

"The Power factor circuit generates a Primary supply which can be read at Fuse F302 160V. This primary voltage is routed through T301 and routed to the Standby 5V supply." That is wrong. Where did you get the info from?

After t301 i have no voltage, betwen pins of c377 i have 0v, relay is mounted without black cover to see whats hapening, n the picture above, where I wrote the voltage of 3.7 v. this voltage starts at 1v and increases if there is more time connected. I do not have the ac voltage in d101 but on the output I find the tension I am talking about above

[budm]

Re: Lg 50pj550 no STBY light

"i dont understand why no have 5v (3.49v)" I do not understand the (3.49V). What is the 3.49V reading?
The 5.1V (switched Q352) and the 17V (switched Q356) are switched power supplies.

[budm]

Re: Lg 50pj550 no STBY light

Is this your EXACT board?

[budm]

Re: Lg 50pj550 no STBY light

Without having the board connected to other board and have Voltage on the main filter caps in the PFC circuit is that relay RL101 has to be closed, so you should verify that is no DC on the coil (measure right across the coil) of RL101. If the coil Voltage is not present then it mans the contact is stuck closed. RL103 is used for bypassing the NTC when PS-ON is present.
What DC V do you have between C377?

"The Power factor circuit generates a Primary supply which can be read at Fuse F302 160V. This primary voltage is routed through T301 and routed to the Standby 5V supply." That is wrong. Where did you get the info from?