Philips 46pfl5505d/f7

[krygods]

Philips 46pfl5505d/f7 no power / standby light.

I've desoldered all the caps and transistors to test and they all tested good.

The discoloration on the back side of the board is from desoldering not leaky caps.

Wondering what the next step would be in troubleshooting the power supply?

Any help, suggestions, or opinions would be greatly appreciated.

[budm]

Re: Philips 46pfl5505d/f7

Do you get 5.3V DCV at the conector CN2 pin 9? You did check main fuse?
Do you get 160~170VDC between the two legs of those two main filter caps in the primary side of the circuit?
http://www.shopjimmy.com/philips-upb...nit-board.htm#

[krygods]

Re: Philips 46pfl5505d/f7

The main fuse tested good and I've checked for AC voltage on both sides.

There is no power at Pin 9 of CN2

The two filter caps are the two largest ones under the largest piece of shielding in the lower center portion of the board?? C800 and C808 - 150uF 400v?

[krygods]

Re: Philips 46pfl5505d/f7

I tested the two caps I mention in the previous post.

Both show 160-170VDC

[krygods]

Re: Philips 46pfl5505d/f7

What would be the next thing to check after making sure those two caps have voltage?

[dick_barton]

Re: Philips 46pfl5505d/f7

There's a service manual which looks as though it has the power supply at:
http://tinyurl.com/o9jdbkh

[budm]

Re: Philips 46pfl5505d/f7

So you do have main DC to run the STBY power supply section.
You board is Delta model DPS-360GP.
We do not have the diagram for the board so we will have to trace out the circuit manually.
So how much times and patients do you have to troubleshoot down to component level?
The STBY section has IC901 for the SMPS, Power transformer T901, startup/running caps c906, the other cap is cover by the white glue so I cannot tell what that C is.
Disconnect the cable to that connector which goes to the main board to see if the 5V will be present, if not then unplug the AC thenyou can try heating those two caps with hair dryer for a few minutes and then reapply the power to see if the 5V will be present.
We will also need the P/N as printed on top of the IC901.
Thanks for the diagram DICKBARTON.
See if the P/N matches the IC901.
Pictures provided by SHOPJIMMY.

[krygods]

Re: Philips 46pfl5505d/f7

IC901 - DNP005 G0923

The capacitor number covered by the white glue is C912

Let me go ahead and do as suggested above and I'll post back with the results.

[krygods]

Re: Philips 46pfl5505d/f7

Didn't see any voltage at Pin 9 with the main board unplugged.

Tried heating caps C912 and C906 with hair dryer and testing still no voltage at Pin 9

[CapLeaker]

Re: Philips 46pfl5505d/f7

check if ZD951 is shorted

[budm]

Re: Philips 46pfl5505d/f7

OK, looking at the diagram, let make sure th Zener diode ZD951 on the secondary side is not shorted out, use Ohm mode to check the resistance between the two legs of the the Zenner.
Also need to check D906, 908, 909, and ZD904 in the primary side.

[krygods]

Re: Philips 46pfl5505d/f7

I'm unsure if I'm testing the diodes correctly so I took pictures of each diode while I tested them.

[krygods]

Re: Philips 46pfl5505d/f7

Last two diodes

[Agent24]

Re: Philips 46pfl5505d/f7

D906 is OK, ZD908 is OK, D903 is OK, D909 is OK

D950, D951 and ZD951 show as shorted, possibly they are in parallel so maybe only one of them is bad.

Your meter needs a new battery too.

[krygods]

Re: Philips 46pfl5505d/f7

Okay, let me go ahead and remove D950 and D951 so that I can test them and then I can also test ZD951 while still on the board because that one is a PITA to desolder.

[budm]

Re: Philips 46pfl5505d/f7

D950 is connected in parallel with D951, the Zener ZD951 (1N5920, 6.2V 1.5W) is for clamping the output of the D950/951.

[Agent24]

Re: Philips 46pfl5505d/f7

Desoldering ZD951 shouldn't be too hard, just make sure you are desoldering the diode from the turret terminals and not trying to remove the turrets from the board, which are probably crimped on as well as soldered.

EDIT: after a better look at the photo, perhaps the diode is crimped into the turrets. I can't see any solder there. Strange!

[budm]

Re: Philips 46pfl5505d/f7

You just need to lift one end off the board.

[krygods]

Re: Philips 46pfl5505d/f7

This is D951

[krygods]

Re: Philips 46pfl5505d/f7

ZD951 and D950