Pana TH-50PX77U dead

[ajshoe]

Have a panasonic th50PX77u thats completely dead (apply power - no clicks or lights) - PSU etxmm655meh.
checked all fuses (4)

no 5V at pin 5 of connector A7 when the
TV is plugged into the AC line

TV unplugged - 1 ohm continuity between pins 8 and 10 of connector P12 of the P board
disconnected A7 conn - set does nothing,
assuming the PSU is bad. looking for diagnostics on PSU - or what to look for ?

does anyone have any diagnostic or repair tips for this PSU ?? I've seen a blog that says replace MC201, MC301 and maybe IC tea1610. Thanks

[tw2005]

Re: Pana TH-50PX77U dead

Are fuses OK on your board? You should really start a new thread.

Not sure if the troubleshooting guide I have is exactly correct for this model. Do you have a copy . It's quite detailed.
since it's dead, no clicks, says first step is

1.Is there 5V at
pin 5 of connector A7 when the
TV is plugged into
the AC line?

NO to step 1
Unplug the TV. Is there continuity between pins 8 and 10 of connector P12 of the P board?

YES to 1

Is
there 3.3V at
pin 6 of connector P7 when the
TV is plugged into
the AC line?

What have you checked so far? Fuses?

tried to start new thread - HOW ????

no 5V at pin 5 of connector A7 when the
TV is plugged into the AC line

TV unplugged - 1 ohm continuity between pins 8 and 10 of connector P12 of the P board

assuming the PSU is bad. looking for diagnostics on PSU - or what to look for ?

probably is a PSU issue.

Unplug the TV.
Disconnect connector A7.
Does the TV turn on by itself
when it is plugged into the AC
line with no picture and lit
LEDs on SS & SC
boards?

If not then PSU.

You have no STDBY 5v so I'd start with the fuses F601,602,501, thermal fuse RF601.

manual and troubleshooting guide should be in Tom's reference library in the sticky.

TRAINING MANUAL

SERVICE MANUAL

you should be able to start a new post from the front page.

,

Start with the basics.

[ajshoe]

Re: Pana TH-50PX77U dead

done the basics - took off heat sink on psu. checked all fuses. RF601 - all good.
no 3.3V at pin 6 of connector P7 when the TV is plugged into the AC line
I'll have to print out psu schematics and start over.

[ajshoe]

Re: Pana TH-50PX77U dead

can't seem to find any info on these ICs - attached PSU schematic and voltage readings. is there panasonic test point voltages out there ???

[tom66]

Re: Pana TH-50PX77U dead

That's the standby supply...
What voltage do you have across C503?

[ajshoe]

Re: Pana TH-50PX77U dead

think I wasn't using correct ground - going to re test. across c503 = +164 volts

[ajshoe]

Re: Pana TH-50PX77U dead

bump

[ajshoe]

Re: Pana TH-50PX77U dead

turns out T501 was open - removed it, had corrosion on windings for this circuit. re-soldered and set works great. Not sure how just 2 windings of this xformer are corroded - maybe some contamination ?? something must have dropped on power board right at this location. Not a fan of this set thou - doesn't have menu button on set - hard to navigate without remote (complaining on a free set !)
On another note - anyone experimented with mip3e3 substitution ?? like sub in mip2e series (3 Pin) ?? The mip3e3 is discontinued and can't find data sheets on it - think the mip2e can be subbed in with some work.

[tw2005]

Re: Pana TH-50PX77U dead

well done with the TV, obscure fault for sure.

The specs on this will be the same http://www.utsource.net/pdf/pdf-MIP3E3.html

Just it's the TO-220 package as opposed to the DIP7.

http://www.alldatasheet.com/datashee...MIP2E3DMY.html