Panasonic TC-42PX14 Zener Diode

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

budm, sorry for not getting back to you. Took a vacation down
in southern Mexico, Morelia Michoacan. I got back a few days
ago, and got frustrated with this tv, I just went and bought
another A-board and tv worked fine. Sold tv on Craigslist.
Not sure if I want to buy another fixer upper, especially
Panasonic Plasma. You are one special guy, always here to
help the community on this Forum.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

OK, I found out where STB3.3V is coming from, (IC5480 PIN8), see PDF.
STB5V (Standby 5V) goes into pin7, an the output of 3.3V comes out on pin8 of IC5480.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

May be that is why you are not getting the signal output from MCU pin 28 to turn on the F15V.
Need to look through the diagrams to see who generates the STB3.3V.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

That out put on the Collector is for sending the SIGNAL (SOS) indicating that one or more of the 4 power supplies have gone out, it is not used for powering the circuits, there should be no output from this transistor if all 4 power supplies are working. So the error light is correct since the transistor is turn on due to failed power supply.
If F15V is not present, then there will no sub1.8, sub1.3, sub5v, sub3.3v.So F15V is the key voltage source. as shown on page 46.
On page 49, are you getting STB3.3V feeding the MCU IC1100?

No, STB3.3v to MCU 1100. More trouble shooting ahead.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Main key right now is that the MCU IC1100 pin 28 is not sending the signal to turn on F15V, that is the bottom line, there is no output from MCU.

Going to get some rest, been reading and listening to your advise.
Will hack at again tomorrow. Thanks budm!

[budm]

Re: Panasonic TC-42PX14 Zener Diode

Main key right now is that the MCU IC1100 pin 28 is not sending the signal to turn on F15V, that is the bottom line, there is no output from MCU.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

That out put on the Collector is for sending the SIGNAL (SOS) indicating that one or more of the 4 power supplies have gone out, it is not used for powering the circuits, there should be no output from this transistor if all 4 power supplies are working. So the error light is correct since the transistor is turn on due to failed power supply.
If F15V is not present, then there will no sub1.8, sub1.3, sub5v, sub3.3v.So F15V is the key voltage source. as shown on page 46.
On page 49, are you getting STB3.3V feeding the MCU IC1100?

I will check it out.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

Line 4 BUSS signal line:
TVSUBON on line 4 is the output from MCU IC110 PIN28 to feed the power supply to turn on IC603, its output is then feed IC502 pin 1 as I have already traced out in the PDF.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

That out put on the Collector is for sending the SIGNAL (SOS) indicating that one or more of the 4 power supplies have gone out, it is not used for powering the circuits, there should be no output from this transistor if all 4 power supplies are working. So the error light is correct since the transistor is turn on due to failed power supply.
If F15V is not present, then there will no sub1.8, sub1.3, sub5v, sub3.3v.So F15V is the key voltage source. as shown on page 46.
On page 49, are you getting STB3.3V feeding the MCU IC1100?

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

I just noticed if you follow line 4 from page 30 it goes to page 31
which leads to MPU

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

More explanations: Page 46, Q5522 monitors 4 Voltages to make sure they are present, SUB5V, BT30V, SUB9V, and FV15V through 4 OR GATES (Dual) diodes D5521, D5522.
That is why it is called VOLTAGE DROP ERROR DETECT since the MCU is not sending out the signal to turn on FV15 as I explained earlier.
Something is locking out the the MCU.

Yeah, I saw D5521 and 5522 on top of A board with the Q5522 in between.
I really thought this was the problem as per panasonic Power Led Blinking
Timing Chart, it gives 4 possible reasons that causes the 10 blinks on A board
and Tuner Power SOS is one of them. As you can see, one end of the
Transistor Q5522 goes to the Tuner on the A board. OK back to the
drawing board. Thanks for your input.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

More explanations: Page 46, Q5522 monitors 4 Voltages to make sure they are present, SUB5V, BT30V, SUB9V, and FV15V through 4 OR GATES (Dual) diodes D5521, D5522.
That is why it is called VOLTAGE DROP ERROR DETECT since the MCU is not sending out the signal to turn on FV15 as I explained earlier.
Something is locking out the the MCU.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

What page this Q5522 is on?

budm, it is on page 30, what do you think?

[budm]

Re: Panasonic TC-42PX14 Zener Diode

What page this Q5522 is on?
OK, I found it, it is an PNP transistor.
For that transistor to turn on, the bottom end of the resistor R5536 will have to go low to let 5VSTBY current to flow out of the Collector pin. When that transistor is turn on, it will send the signal indicating that there is power supply failure, it should be normally OFF.
D5521 and D5522 are setup as an OR gate, if the Cathode side goes low due to missing power to make the Diode forward bias, then Q5522 will conduct which indicate one of the 4 power supplies had failed. Since you do not have F15, that means the top Diode of D5521 will be forward bias, so it turns on Q5522, so you will get error light.
That is why we need to get the F15V to work.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Well, I am pretty sure my problem with the Blinking 10, at least in my
unit is Q5522. It is a transistor, not sure if it is NPN. Schematics or
part #B1ADCE000022 will identify what type of transistor it is. I did
a google search and could not find info, other that it is out of stock.
According to page #30 of Schematics it says TUNER SOS below the
words it says LED:10 TIMES, I followed the black line and it goes to
the Tuner of A board., it also goes to TV SUB ON via pin 14 Connector
A6, that of course goes to Power Board.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

"“TV_SUB_ON” Command (3.2V) and the PANEL_STB_ON” command (3.2V).
The “TV_SUB_ON” command is provided to pin 6 of connector P7 of the power supply through pin 14 of
connector A6 of the A board to develop the F_STB+15V. At this time the relays on the power supply are
triggered and a “click” sound can be heard." and "This SOS Detect circuit is controlled by the TV_SUB_ON command from the Main
CPU (IC1100)."
So at this point the IC1100 is not putting out the TV_SUB_ON signal that I traced it back to IC1100 are due to? Who is controlling the TV_SUB_ON?

budm, Yesterday I mentioned that my A-Board did not have IC9004
well, I did find it on Page 31, it is next to IC 1100. I followed the sub 9v,5v and 3.3v from Page 30, the sub 3.3 and 5v, come from IC 5607 and the
sub9 from IC 5401, from there they go to IC 1100
IC 9004 is a 32 pin. I am hoping one of the components that go to IC 1100
that are fed from IC 5607 or possible bad IC 5401.
I also note after IC 9004, from there it goes to IC 9003 a pin there goes to
Connector A25, that is Main Panel On. pin 11, which should have 3.2v. There
is no reading there. Of course from there it goes to P board to turn on the F15v

[budm]

Re: Panasonic TC-42PX14 Zener Diode

"“TV_SUB_ON” Command (3.2V) and the PANEL_STB_ON” command (3.2V).
The “TV_SUB_ON” command is provided to pin 6 of connector P7 of the power supply through pin 14 of
connector A6 of the A board to develop the F_STB+15V. At this time the relays on the power supply are
triggered and a “click” sound can be heard." and "This SOS Detect circuit is controlled by the TV_SUB_ON command from the Main
CPU (IC1100)."
So at this point the IC1100 is not putting out the TV_SUB_ON signal that I traced it back to IC1100 are due to? Who is controlling the TV_SUB_ON?

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

OK, you can remove the jumper.
I look deeper in the diagram and find that the F15V command comes from the IC603 PIN 16, the control signal to turn on pin 16 is fed into IC603 PIN9 (this signal is called by many names, F_STBY_ON or TV SUB ON or AG_TV_SUB_ON), this signal comes from SYSTEM MPU IC1100 PIN28. So some how this MPU is not sending out the signal to turn on this F15V REGULATOR IC.
I do not have complete understanding on how this MPU works, it may be in the locked-out mode due the error detection some where, this is about as far as I can go for you,.
The bad part about this service manual is that they keep changing the name of the signals, hard to trace them out.

The power command from the power switch on the S board or the remote control receiver on the K board is
provided to the Main CPU on the A board (IC1100) thru connector A1. The CPU on the A board outputs the
“TV_SUB_ON” Command (3.2V) and the PANEL_STB_ON” command (3.2V).
The “TV_SUB_ON” command is provided to pin 6 of connector P7 of the power supply through pin 14 of
connector A6 of the A board to develop the F_STB+15V. At this time the relays on the power supply are
triggered and a “click” sound can be heard.
The F+15V from the P board is applied to several voltage regulator (IC5603, IC5401, and IC5607) on the A
board.
The voltage outputs from these ICs are called SUB5V, SUB9V, SUB3.3V, SUB1.8V, SUB1.3V, and BT30V.
They used by various circuits on the A board.
To avoid catastrophic failures, they are monitored by an SOS Detect circuit (IC5480) for over-voltage and
over-current conditions. This SOS Detect circuit is controlled by the TV_SUB_ON command from the Main
CPU (IC1100).
Any abnormalities of the SUB5V, SUB9V, or BT30V triggers the SOS circuit. The TV shuts down and the
power LED blinks 10 times.
The “PANEL_STB_ON” is used to turn on the 3.3V regulator (IC9004) on the A board. The output voltage is
applied to the “Panel” CPU on the A board (Formerly located in the D board).
The Panel CPU on the A board outputs the “PANEL_MAIN_ON” Command (3.2V) to pin 11 of connector
P25 on the P board.
The PANEL MAIN ON command turns on the power supply circuit that outputs the Vsus, Vda, 15V, and 5V

My A-board does not have IC9004, also I do not get the 3.2v on pin 11 of
connector P25 on PB.
I did find a 5pin voltage regulator on page 72 of A-Board
This could be the reason pb will not turn on, I have to find why 3.2 is not
reaching pin 11 on A25 connector and then feed it to P25.
Thanks for all your help, please let me know if something pops up in
your mind. I will now pay my attention to the A-board.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

OK, you can remove the jumper.
I look deeper in the diagram and find that the F15V command comes from the IC603 PIN 16, the control signal to turn on pin 16 is fed into IC603 PIN9 (this signal is called by many names, F_STBY_ON or TV SUB ON or AG_TV_SUB_ON), this signal comes from SYSTEM MPU IC1100 PIN28. So some how this MPU is not sending out the signal to turn on this F15V REGULATOR IC.
I do not have complete understanding on how this MPU works, it may be in the locked-out mode due the error detection some where, this is about as far as I can go for you,.
The bad part about this service manual is that they keep changing the name of the signals, hard to trace them out.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Solder pin 3 and 4 of the Opto IC600 together, then plug the TV in, then you should see IC603 pin16 and PIN1 of IC502 goes HI.

I soldered the pins 3 and 4, and IC502 dc voltage reading is 00.03v pin 1