Panasonic TH-42PZ85E --> Completely dead!

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

10ms/div doesn't make any sense if you only got one pulse. That's a pulse only 10Hz, you need 100Hz (one pulse every 10ms)

No bridges at all, back to the original condition, check AC_DET again.

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Sorry your right. I need to measure it again and make sure that i get 2 pulses so i can measure the HZ

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

So i measured again! Hope i did it right.

Pin 16 of mc501

time/div is 5
volt/div is 5

Result is in the picture.

Time div on 2 i only get 1 pulse on these settings.
If i alter the arrow button i get 2 pulses.

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

This picture is 2ms time div.
Used the arrow potmeter on time/div to get 2 pulses on the screen.

Volts div is 5.

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

Don't use the UNCAL position (the arrow) as it does not tell you the actual timebase. Always switch to a fixed timebase, even if there are more than two pulses and always lock the arrow in the CAL setting.
(The adjustment is only there for very specific uses requiring a fine timebase and no reference. It is almost never used.)

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Ohm readings.

P11/Going to SS board.

Pin 1 White : Starting at 18MOhm counting down….
Pin 2 Grey : 0.2 ohm.

P2

Ground vs Pin 1 = OL ?
Ground vs Pin 3 = 0.8 ohm.

Does this help determine the problem? According to the manual its P board which we already knew but it might shine some light on the part thats causing the problem…

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Ok i only used the arrow with the 2ms time div. If i don't use the arrow i get 1 pulse over the whole screen as seen in earlier pictures.

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

Ok, so you are saying on 5ms/div you get those two pulses shown HERE:
https://www.badcaps.net/forum/attach...0&d=1414777927

The spacing between them is critical so please verify this because right now it does not make any sense. It would indicate your mains frequency is 33Hz or 66Hz.

(6 divs = 30ms, 1/30ms = 33Hz, possibly freq-halved from 66Hz)

In the Netherlands the mains frequency is 50Hz so you should see a pulse either every 20ms or 10ms (2 or 4 divs on 5ms/div)

Again please make CERTAIN the arrow knob is locked into the CAL position, it can be fiddly with older scopes.

There's no conceivable way that the circuit could fail to produce a wrong frequency output, IMHO.

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Ok will measure again! Both arrows in CAL position or only the time/div?

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

All adjustable arrows locked in CAL please.

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

Here is what I measured on pin 14 of my set.
One pulse every ~10ms or ~100Hz.
(Quick and dirty measurement: ground lead wasn't properly grounded so please ignore the noise.)

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

This is what i get! Picture is not good Because its.flickering.
I get squares inbetween the 2 pulses.

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

Was that at 5ms/div? So that is 100Hz, as expected.
That's annoying, because it eliminates that as a fault.

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Yes at 5ms/div!

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

So …were running out of options right? :P

Should i try to desolder some parts and resolder them with some new tin? For example the IC's on the MC201/301? Or are those parts not involved on the 5v?

Ps , Pin 10 of P12 is 1.8v. Schematic says 12v?

[tom66]

Re: Panasonic TH-42PZ85E --> Completely dead!

No, MC201/MC301 aren't active in standby so would not cause your issue.
Try checking pins of MC701 (CPU module)

- pin 31 - should have ~4.5V on it
- pin 30 - have a look on a scope at 1ms/div 2V/div, I will compare

Check STB_PS (pin 10 of P12) with main switch pressed and released...

STB_PS has R557, a 3.9k resistor, in series from 5V standby unswitched. Check it is not open circuit.

Maybe MC701 is bad. If the user is correct about the spark, it could have travelled up into MC701 causing damage.

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Pin 31 = 4.8v
Pin 30 = 2.1v with multimeter.

Pin 10/P12 = 5v and pressed is 1.8v.

R557 measures 3.9K over Pin 10/P12.

Picture from Pin30 with scope coming in a min..

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

Its very hard to reach with the probe.
The default horizontal line is in the middle.

With 1ms/div 2V/div the line goes 1 square upwards. ( which means 2v right? )

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

It stays horizontal ( flat )

[Moreno83]

Re: Panasonic TH-42PZ85E --> Completely dead!

R557 = short!!

I had the power button switched on which measures 3.9K. when measuring and pressing powerswitch the multimeter says -OL
Or is that ok ?