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Discussion Starter #1 (Edited)
NO VIDEO : Phillips 64PH9905 [Year 2000, 64" RPTV w/built in HD tuner]

Hi All !!

Newbie poster here...
not new to electronics though...
but TV's give me a headache


My Y2K (remember that?) Phillips that cost me
10 grand back in 2000 has decided to go
on summer hiatus.

While watching the TV I noticed a flash of sorts
with a ringing pattern on the screen... a quick
channel change showed the same ring and
then I said UH-OH . . .

I powered it off... said a "HAIL MARY"...
but alas when I powered it back on there was

- NO VIDEO (neither tuner nor inputs)
- AUDIO is GOOD
- TUNER does change channels (audible)
- Remote works

There were NO burnt electronic smells.
NO visble scars on the internal SCAN PC Board (pictured below)
NO visably fried components (scan board).
NO apparent wiring anomalies.

and YES I did unplug the unit to do a master reset.

Well I'm ready to get into this deeper.
Any suggestions would be appreciated.

I figure it's somewhere in the High Voltage (?)
Scares me to yank out the board and start buzzing it
but I am prepared to take a deep breath and dive in.

But first I figured I'd consult all you experts.
I've read such sage postings from so many on here.

And I am especially in awe of Leonard C . . .

YOU da MAN !!
 

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Plain ole user
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Please be more descriptive with regard to "flash of sorts with a ringing pattern on the screen."
 

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Discussion Starter #3 (Edited)
Perhaps "flash" is not the correct word.
(although I did see 10 grand FLA$H before me)

Keep in mind this was a mere 5 second period
where the picture began to shrink horizontally...
colors were intact.

The ringing refers to what I seem to recall
was the picture being enveloped in a damped
sinusoidal oscillation type of pattern...
sort of the way a circuit "rings".

I quickly changed the channel to see if it was
on the adjacent channel (to rule out the broadcast)
and it looked the same and that's when I shut it off
and said UH-OH...

...all this took place in 5 secs

NO VID when I turned it back on 10 seconds later.

So I guess the best description would be:

a 5 second shrinking horizontal picture w/colors intact
that had some kind of oscillation/modulation to it...
and then after powering off and then back on...

- NO VIDEO (neither tuner nor inputs)
- AUDIO is GOOD
- TUNER does change channels (audible)
- Remote works

There were NO burnt electronic smells.
NO visble scars on the internal SCAN PC Board
NO visably fried components (scan board).
NO apparent wiring anomalies.

and YES I did unplug the unit to do a master reset
.

( Now I know how those crime victims feel when
they are asked to describe their assailant !! )
 

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Plain ole user
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Could be lots of things, but it sounds like you lost horizontal output. I would be starting with power supply checks and that.
 

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Discussion Starter #6
UPDATE Re: NO VIDEO : Phillips 64PH9905 RPT

UPDATE:

I've been slowly chipping away at my Phil now that
I have that Service Manual !!

All voltages on the POWER SUPPLY BOARD are good.

The CRT PROTECTION circuitry is indicating Sweep Failure.
CRT Protect line is High, thereby causing the High Voltage
to go into shutdown mode. (see attached)

The scan circuitry and HV power are all on the SCAN/HV BOARD (duh!)
I plan to back track this further and still expect to find
the problem on the SCAN/HV BOARD but I wonder if it is
possible that the problem could be on another board?
SYNC CONDITIONER? CONVERGENCE? MICROPROCESSOR?

Care to venture a guess as to what component(s) are the culprit?
(most likely NOT in the below schematic)

I have attached a ZIP file containing 2 JPEGS

- The Overall Block Diagram
- The High Voltage Output Circuit w/description.

Any and all thoughts are GREATLY appreciated.
 

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Plain ole user
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Bad solder connections and CRT drive ICs are not uncommon failures in these sets.
 
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