Philips 47PFL5704D F7 No Power

[retiredcaps]

Re: Philips 47PFL5704D F7 No Power

I tested the cap with the diode tester function and got those results are they good results?

Inconclusive. For example, a 1000uF cap might only be 680uF, but test "good" on a resistance test.

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Does you Fluke measure capacitance? If yes, measure C121 and see if it matches the sleeve value.

This one is s Fluke 75 series 2 Multimeter as no cap tester function on it. I tested the cap with the diode tester function and got those results are they good results?

[retiredcaps]

Re: Philips 47PFL5704D F7 No Power

on my fluke

Does you Fluke measure capacitance? If yes, measure C121 and see if it matches the sleeve value.

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Yes, but lately a lot of people haven't been reporting what they see on their multimeter because they don't know how to interpret it.

a) 0L on an autorange multimeter means open loop or infinitiy or out of range.

b) 0.0 is a unit of measure.

c) On manual range meters, "1" on the left hand side means the same as 0L.

d) Some people report "no reading" when they see "1" on the left hand side. This is easily the #1 mistake.

e) Some people report the quantity, but not what they are measuring (volts, ohms, etc).

f) Some people report 1.00 ohm, but it is really 1K ohm, because they forget their dial is set on 2K.

PS. Your diode is good. If you had reported 0 (zero), then it would be bad.

I have an auto range meter and now I see what your saying...thanks for the tip.

So both seem to be good I assume....

[retiredcaps]

Re: Philips 47PFL5704D F7 No Power

Sorry it goes to .0L on the meter when I test it with the diode tester on my fluke....did I test it correctly?

Yes, but lately a lot of people haven't been reporting what they see on their multimeter because they don't know how to interpret it.

a) 0L on an autorange multimeter means open loop or infinitiy or out of range.

b) 0.0 is a unit of measure.

c) On manual range meters, "1" on the left hand side means the same as 0L.

d) Some people report "no reading" when they see "1" on the left hand side. This is easily the #1 mistake.

e) Some people report the quantity, but not what they are measuring (volts, ohms, etc).

f) Some people report 1.00 ohm, but it is really 1K ohm, because they forget their dial is set on 2K.

PS. Your diode is good. If you had reported 0 (zero), then it would be bad.

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Is that 0 or 0L on your multimeter? It makes a big difference.

Sorry it goes to .0L on the meter when I test it with the diode tester on my fluke....did I test it correctly?

[retiredcaps]

Re: Philips 47PFL5704D F7 No Power

D107 is showing .452 and 0 in reverse

Is that 0 or 0L on your multimeter? It makes a big difference.

[kolpro]

Re: Philips 47PFL5704D F7 No Power

D107 is showing .452 and 0L in reverse
C121 has a reading for about 1 or 2 seconds then go to 0

The resistance between pin 5 and 1 is 15.5k

I blew the fuse (6.3ah 250vp) when I hooked it back up today to test for voltage I'm wondering if I can get one from radio shack?
Should I put these components back in?

[momaka]

Re: Philips 47PFL5704D F7 No Power

Check D107 and C121 out of circuit.
D107 should show a reading only in the forward direction under diode test (i.e. red probe on anode and black probe on cathode (cathode is the side marked with a white stripe)).
C121 should go open-circuit after holding the probes on it for a second or two.
If those components are fine, measure the resistance between pin 5 (Vcc) and pins 1/2 (hot GND).

[PlainBill]

Re: Philips 47PFL5704D F7 No Power

Question....can I test the caps and diodes for shorts while in the circuit or should I just pull them out and test them?

You can test them in the circuit. If you get ambiguous results (a diode that shows 1K in both directions), it should be removed and tested. If you get a low resistance (less than 200 ohms) across a cap, SOMETHING is shorted and causing problems.

PlainBill

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Question....can I test the caps and diodes for shorts while in the circuit or should I just pull them out and test them?

[PlainBill]

Re: Philips 47PFL5704D F7 No Power

Could also be an open resistor in the charging circuit.

I don't think so. 'resistor in the charging circuit' is ambiguous, there are two possible meanings. There is a high value resistor from the filtered mains voltage to pin 8. Given the reading at pin 8, that resistor is good. While it is not shown in the app note, there often is a series resistor in the tertiary winding - diode - Vcc cap circuit. If that resistor were open, the smps would start, then die as Vcc dropped below the threshold.

PlainBill

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Could also be an open resistor in the charging circuit.

Resistor R104 was showing 194k ohms before I replaced the chip now it shows about 33. k ohms with the new chip in.

R104 -- 196k ohms

All the above testing was done in circuit as well.

[tom66]

Re: Philips 47PFL5704D F7 No Power

Could also be an open resistor in the charging circuit.

[PlainBill]

Re: Philips 47PFL5704D F7 No Power

The voltage on pin 5 leads me to suspect the diode on the tertiary winding or the Vcc cap is shorted. As momaka said, this is a VERY simple circuit.

PlainBill

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Thanks again I just posted multiple pics to make sure that you can see them good.

[momaka]

Re: Philips 47PFL5704D F7 No Power

Interesting...
Pin 5 (Vcc) needs to be at least 8.7V in order for the FSQ510 to start and continue to be no less than 6.7V for the FSQ510 to keep operating. Should there be a fault, data sheet says the voltage will fluctuate between 6.7V and 8.7V. The fact that it's not suggests that perhaps Vcc is being pulled low by a shorted component.
The voltage on Pin 3 (Vfb) should also be close to 2.8V when the PSU is operating normally and 4.7V when in overload protection. Getting zero for this one likely means the PSU is not even trying to start.

If possible, post a few more pictures of the PSU - one capturing the underside of the whole board and 1 of the topside again capturing the whole board. The FSQ510 data sheet has a sample circuit on page 2. It looks pretty simple. I think we should be able to figure out the circuit in your PSU without a schematic pretty easily. Just need good pictures.

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Here are the readouts.....I used pin 1 as ground

pin 8 -------147 volts
pin 5 ------- 0 volts
pin 3 ------- 0 volts

Thanks again!

I was trying to find a schematic of this board but can not.

[momaka]

Re: Philips 47PFL5704D F7 No Power

With the FSQ510 chip installed in the circuit, measure the voltage on pin 3 (Vfb), pin 5 (Vcc), and pin 8 (Vstr). Post what voltages you get. Use pin 1 and 2 (GND) as ground or use hot ground (the "-" of the bridge rectifier on the primary).
Try to perform the test fairly quickly (i.e. don't apply power to the TV for too long). This is to prevent anything else from going bad.

[kolpro]

Re: Philips 47PFL5704D F7 No Power

Ok I installed the FSQ510 chip and still no power to the TV........