Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

[AtomicPunk]

Phillips - Model 42PF7421D/37 - Chassis EL1.1U AA

No display - 2 long, 5 short led blinks - is this error code 25?

I've downloaded the training manual and chassis manual from another thread. Lot of information to try to digest.

I see no visible capacitor issues - fuses checked and are ok.

Any tips on voltage check points would be appreciated.

[R_J]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

The standby +5.2 volts on plug IM46 pin7(see page39) should be there becaue you have the error code being flashed.
Check if you also have +8V6, +12V on the SA2 standby board (see page 151)
Do you here any relays click when you press the power button?

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

Relay does click when i hit power button; red led flashing stops; but no display or backlight activity. If I hit power button again; relay click, and red led flashing resumes.
I will check the voltages tomorrow morning. Thanks for the references and page numbers.

[R_J]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

So you could just have a backlight issue? Does the backlight flash once when first turned on, also can you see an image if you shine a light (torch/flashlight) at the lcd screen? You may need to hit the menu button to give a image.

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

Observed voltages - I would measure, toggle the power button as well.


1M03 - to 1J02 - B01B Supply
9 +5V2-Relay-IO2_PWM - observed +5.3 goes to +5.4 when relay click
4 GND


1303
1 >1v, 24v with relay click returns to >1V
2 >1V, 24v with relay click returns to >1v
3 nothing
4 nothing

1304
1-2 +12_24v (expected) - observed 0, +24v with relay click, returns to 0
3-4 +12v (expected) - observed: 0,+12v with relay click returns to 0

1305 A1 LCD Supply
1-2 +5V2 (expected) - Observed: +5.3v
3 ??? - observed: +5.3v, but drops with relay click, returns back to 5.3v



1309
0

1316
1-5 +12V_24V (expected) - observed: 0, +24v with relay click, returns to 0

1317 To Display
1-5 +24V_2 (expected) - observed: 0, +24v with relay click, returns to 0
1.5v, 24v with relay,1.5v


1320
1-3 - 0

1806
1 +5.3v
2 +5.3v
3 +5.3v, with relay click would drop, return to 5.3v

1M02
1 observed: >1V, -18V with relay click, returns to > 1V
2 observed: >1V, -18V with relay click, returns to > 1V
3 0
4 0
5 observed: >1V, +18V with relay click, then returns >1V
6 observed:>1V, +18V with relay click, then returns >1V
7 0

1M01
1 0
2 +2V, when holding power button drops to 0, letting off the power button returns to +2V
3 0

1M21
1 +1.2-1.3V
2 0
3 +2.7
4 jumps around 0 to +2.7V
5 +5.3V constant
6 >1V, with power jumps to 2.7V

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

I have only witnessed the backlight flash once; as I was testing applying/removing power at different intervals. I don't believe that the display is working and that it's a backlight issue, I have not witnessed anything on the display with a flashlight.

[R_J]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

Do you have +8.6Volts (+8V6) on pin3 of 1M46? It seems all the other supply voltages are ok but the standby control ic is turning the tv off. I never did like Philips, they complicate the shit out of a simple tv.

As for the backlights, I would inspect both of the inverter boards, I suspect there is a problem either with the inverter or maybe a bad ccfl tube. and the tv detects the problem and shuts down
I know Philips has had problems with the caps on their smaller inverter boards

[RJARRRPCGP]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

Is Phillips using a Sharp panel or uses the same error codes as Sharp? If true, then I suggest that you go here:

Could it be related to this?

https://www.badcaps.net/forum/showthread.php?t=48477

[R_J]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

Not the same problem, The codes are not related.

[RJARRRPCGP]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

OK, thank you.

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

The diagram I am referencing is below

1M46
1 GND
2 GND
3 NC
4 NC
5 NC
6 NC
7 +5V2 STBY - observed: +5V3
8 NC
9 +12V - observed: 0, goes to +12V with relay click, then drops
10 NC
11 +12V - observed: >1V, goes to +12V with relay click, then drops

1M03
1 BCKLIGHT CTL - observed: 0V, .1V with relay click, then drops
2 NC
3 LAMP ON - observed: >1V constant
4 GND
5 NC
6 NC
7 STANDBY 0(3.5V) - observed: +3V5, with relay click would drop, then return to +3V5
8 NC
9 +5V2 STBY - observed: +5V3 constant
10 NC

I also tried disconnecting 1M02 to eliminate audio amplifier - same result 2 long, 5 short red led flashes

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

I also observe ~+165VDC on connector 1306

[R_J]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

connector 1306 is just the main 160vdc voltage from the bridge rectifier. Did you have a look at the master and slave inverter boards?

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

I looked at the top side of the inverter board next to right speaker - didn't see anything wrong; I've tried operating with the right-hand disconnected; and the left-hand disconnected; also tried disconnecting one side; then the other on the TConn - same results - red flashing; hit power button twice to get relay click

[AtomicPunk]

Re: Phillips 42PF7421D/37 Chassis EL1.1U AA - 2 long, 5 short blinks no display

I've checked the fuses on the inverter boards and they are fine.
Did notice that if I unplug 1304/1309 and plug in the power; that the red led flashing switches to 6 quick flashes.