Mulja tv repair portal
Equipment Repairs => PLASMA TV forum => Topic started by: graham180371 on April 08, 2011,19:09:33
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can any one help me with this? is this an easy fix or is me tv up the spout.
is it as simple as blown capacitor?
any info would help ive seen something about blown PA5400 protector on PA PCB.
but what the f*** is it and where is it. pic would be great if anyone can help
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Subject: TV shuts down with a 10 blink error
Model(s) Affected: TH-42PZ81B, TH-50PZ81B, TH-42PZ82B, TH-42PZ80B
10 blinks indicate problem on A PCB LT rails.
These LT lines are all made from FTSB15v rail (from PSU) going from P6 (PIN 7) TO PA5 (PIN 8)
THROUGH FUSE PA5400 ON PA PCB AND OUT FROM PA6 PIN 8 to A PCB (A6).
Check 15VSTBY is getting to A PCB by checking 15v on PA5 and PA6 as above.
A blown PA5400 protector on PA PCB may be the problem.
This can be caused by the metal coated ‘earth’ sponges (located around the metal housing
for the PCBs). These may slip off (when dismantling the unit) and then touch the HC or XS
circuit boards.
The PSU switches out the 15VSTBY rail when P7 pin 6 (TV SUB ON) goes high > control
signal comes from A PCB. This allows the A PCB to fully boot up and tell the D PCB to turn
on remaining rails.
The remaining PSU rails come up when P25 pin 11 (PANEL MAIN ON) goes high >control
signal comes from D PCB.
10 blinks may also be activated by other PCBs loading the 15v rail (derived from the same T301
transformer in PSU) which supplies the FSTB15V rail.
So a heavy load on the switched 15V may be causing the T301 shutdown and stopping the
sensed FSTB15V rail. Thus giving 10 blinks
To isolate these various boards from the 15v rails in turn:
1. Disconnect SC PCB totally to eliminate this side
2. Disconnect SD card reader > GS PCB connector A9
3. Disconnect front HDMI PCB > GH PCB > connector A11
4. Disconnect SS PCB totally but link out pins 10 and 8 of p12 connector to simulate on/off switch
5. Unplug and isolate the HC PCB which has the audio amp on it (driven from 15v rail).
6. Check PA PCB PA6 connector rails are coming up
PIN 8 > 15V (input from PSU)
Outputs from IC5501 on PA PCB
PIN 13 SUB5V
PIN 16 > DTV9V
7. Unplugging, P6, P7, A3 and A5 will allow the set to run with no front led and producing a white
test pattern.
This is useful for isolating the A PCB
8. Check there is no short circuit on the
70v VDA line > P12 pin 1
Vsus line > P11 pin 1
If these checks fail to reveal problem then most possible cause is a faulty PSU (P) or D PCB i.e.
the 15v drops under full load
9. The PSU can be checked as a stand alone unit.
• Disconnect ALL output connectors from PSU
• Connect a 100W lamp across the Vsus line
• Ensure the on/off switch is linked out on P12 pins 8+10 using a paper clip into connector
holes
• Send in 3v into P25 pin 11 (PANEL MAIN ON) to turn on the PSU
• The PSU should turn on and drive the lamp allowing all output rails to be checked
• Failure to remain on could indicate a faulty PSU
10. Check the impedance on the D PCB rails:
P25 connector > pin 1 (15V) and pin 6 (5V) rails to D PCB for any shorts
Service Hints:
• TH42PZ81, TH42PZ80, TH42PZ82, TH46PZ81, TH46PZ80 SERVICE HINT:
Unplugging, P6, P7, A3 and A5 will allow the set to run with no front led and producing a white test
pattern
This is useful for isolating the A PCB
• Unplugging A5 will allow the D PCB to produce a white test pattern and is useful for
eliminating video faults caused by A PCB.
:beer:
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Hmmm,
I think that may well have frightened Graham away!!
Brian
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lol no i was busy ive tried the white screen test and nothing at all so am gusseing power board is naff trying to find replacment.
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update was power board, up and running now ebay £49
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I am resurecting this thread as I have the same 10 blink fault but on a different set, a TH46PZ85B. Different part numbers and different component and connector references, but the same fault.
I ONLY have 5V standby. There is no 15V from the main PSU.
What I can't understand is should there be +15V from the main PSU when the set is in standby? I get nothing.
I assume at start up, even if not on in standby, it must power up the +15V briefly in order to check the A board low voltages. I don't see any transient activity on the +15V even briefly at first power up.
I am possibly looking at a PSU repair as the only PSU#s I can find are £100 which I think is too much. The PSU on this set is ETX2MM704MG
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Hi Dave, never had any luck powering a Panasonic PSU out of the set, on the bench. Their startup sequence is too convoluted for that.
Here's the sequence for TH-47PX7 and you'll see why.
Bruce
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See in the other similar thread. I "fixed" it by removing the little chop capacitor from the little sub board.
Now it's working it's clear it goes through a complicated start up process and it was obviously failing early on with the 15V missing. My confusion was how does it know this fault when it is in standby, and the answer is this set does not power up into standby, it tries to start up straight away.