Panasonic TC-42PX14 Zener Diode

[mr.sky]

Hello, this Zener Diode is on the A-board, it is part of
the 15v rail that leads to IC5608 and 5607. In an earlier
post I have attached the Schematics.
Can someone identify how many volts this Zener Diode is.

Panasonic parts does not identify the Diode. Suppose they
want you to buy from them. Unfortunately they do not
stock it.
Thanks!

[Mt.Man]

Re: Panasonic TC-42PX14 Zener Diode

Do you have the diode location number Dxxxx?

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

D5573 It is near the 9v regulator IC5401

[JimmysTGP]

Re: Panasonic TC-42PX14 Zener Diode

I must be blind, read me the colors off the diode.

If it is a red, Black, Green. Then it is a RLZ12

[budm]

Re: Panasonic TC-42PX14 Zener Diode

Can you please give me the link to that schematic?

[Mt.Man]

Re: Panasonic TC-42PX14 Zener Diode

Panasonic part number B0BC01100001. However they do not say what voltage rating it is. Its on the output of IC5401 which is the Sub9v. Most likely used for protection. Just guessing maybe 10v or 11v. Input to IC5401 is 15V.

[JimmysTGP]

Re: Panasonic TC-42PX14 Zener Diode

I guess theirs two ways we can attack this, but if your ability to see the diode as well could ultimatly swing the other. Just remember your dealing with a LL-34, hope this helps.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

If it is used as a protection, that means its Zener voltage point will be higher than the output voltage of the IC5401, so the circuit should still function without it and you can also measure the output voltage of the IC5401 and then use Zener Diode that is about 2V higher than the output voltage.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Sorry guys, did not respond yesterday. Ended up in hospital
with Great Pains in Abdomen, after Ctscan, I have a Inflamed
Colitis. So much for that.
yes, the color is red, black green.
I am not getting 15v to the diode or to IC5401, reading is
5.4v to both components.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Can you please give me the link to that schematic?

budm: here is the link to Schematic

http://www.mediafire.com/file/pgdrdbmc2ynu9km

[budm]

Re: Panasonic TC-42PX14 Zener Diode

It is big download file, downloading it, can you please point to which page this circuit is on?

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

It is big download file, downloading it, can you please point to which page this circuit is on?

Page 30 and 46

[budm]

Re: Panasonic TC-42PX14 Zener Diode

Ok, the IC5401 is a 9V voltage regulator, so the Zener Diode may be 12V Zener.
So next thing for me is to find out what generates the F15V source.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Ok, the IC5401 is a 9V voltage regulator, so the Zener Diode may be 12V Zener.
So next thing for me is to find out what generates the F15V source.

budm, read Slide #28 the last paragraph. I think this is why
I am not getting F-15v from outpins from power supply board.
There is a 3.3v 6pin voltage regulator on the component side of
the A board, maybe this is the one that triggers the command to
to acitivate the The PANEL MAIN ON command turns on the power supply circuit that outputs the Vsus, Vda, 15V, and 5V.
Let me note my A-board does not have IC 9004

[budm]

Re: Panasonic TC-42PX14 Zener Diode

OK, I figure out where the F15V is generated from, see PDF/JPG attached.
This F15V is called F15V_STBY which is the always on standby power supply.
So you need to check the voltage at the IC502 which generated the regulated F15V voltages for a lot of circuits as I redlined.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

OK, I figure out where the F15V is generated from, see PDF/JPG attached.
This F15V is called F15V_STBY which is the always on standby power supply.
So you need to check the voltage at the IC502 which generated the regulated F15V voltages for a lot of circuits as I redlined.

budm, Thanks for the diagrams. let me update you and others who
are following this thread.
On first diagram where IC502, I am not getting 15v at all.
Before I press the power button, reading is at 3.0v. Once
I power up unit it goes to 5.4v, same reading I get at the
A Board at IC 5401 and IC5608.
Also, Pins 7,8,9 same voltages at connector P6.
The unit is only come on for a few seconds, enough to take
a reading then shuts down within 5 seconds.
Note, I took the reading from pin 4 of IC502

[budm]

Re: Panasonic TC-42PX14 Zener Diode

IC502 is the standby power supply (15V) which should be always running. The other power supply circuits is right below it is also always on, do you get any voltage there? There should be voltage at Q505, that section is for the standby 5V power supply.
Basically, transformer T200 is for standby 5V and standby 15V power supply, so you MUST have these voltages.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

IC502 is the standby power supply (15V) which should be always running. The other power supply circuits is right below it is also always on, do you get any voltage there? There should be voltage at Q505, that section is for the standby 5V power supply.
Basically, transformer T200 is for standby 5V and standby 15V power supply, so you MUST have these voltages.

I will check it out, I also tried another new power supply board
that I received last week. And the same results.
Who knows could be bad too, good thing I got it for 30bucks.
I am looking at page 32, and on top of board, there is a 3
leg diode, looks like a regular size voltage regulator, but it is
a diode, D502. Going to have lunch and test voltages like you
mentioned above.

[mr.sky]

Re: Panasonic TC-42PX14 Zener Diode

Will take those voltage readings tomorrow, seems my Amprobe 38
meter, needs another battery. Readings flucuate.
budm, so standby should always be there, without powering up
unit, correct? The only voltage i get on P6 connector is the
5vstandby. That is with just the power cord plugged in.

[budm]

Re: Panasonic TC-42PX14 Zener Diode

Yes, the standby power supply will start running the minute the power plug is plugged into the outlet. All TVs need standby power supply to run the processor on the main board and the remote receiver so it will be ready to take command to turn on the rest of the power supplies from the power switch or from the remote control. This is how TV uses less power when it is not on.
Are you getting any DC at IC502 PIN2 VCC input pin? and the voltage reading on the rest of the pins of IC502.
Since you are getting the 5V, that means the transformer is working.