Faulty Philips PSU (715g5246-p01-000-002s )

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

Zd9303? if you keep the pin shorted, will it stay at 5.7 or it cycles even when the pin is shorted?

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

It cycles with the pins shorted

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

That is not normal. Did you replace the start-up caps C9336, C9337? The filter caps are also check OK?

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

I know. I´v checked the Voltage on the shorted opto. It cycles, too. Will check those Caps next.
What filter Caps do you mean exactly?

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

C9340, 9341. by the way, do you have any other board connected to this 5.2V output connector?

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

By the way, what DC voltage are you getting at the VCC pin5 of IC9301?

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

All the mentioned caps are fine. I have nothing attached to the 5.2V connector.
Pin 5 VCC is 11.75V

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

So that is OK, the under voltage shutdown is 8.1V per spec sheet. I am running out of the ideas where to check next.
What I do not get is that "0.8V with new opto still installed.", it just does not make any sense.

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

With C9334 removed, i only get 0.4V......strange......

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

Leave Zener ZD9303 out since the IC has built-in 12.8V Zener at pin 4 (FB). That cap is 1N, .001 uF. Do you have new cap to try?
R9301 (at pin 1 of the IC) shows about 1.2 Ohms?

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

Larger cap means lower voltage on pin4.
R9301 Shows 5.3ohms and 4.8 when pulled up

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

With R9303 removed i get 9.5v on Pin 4

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

"R9301 Shows 5.3ohms and 4.8 when pulled up" That cannot be right, Per diagram, that R9301 at pin 1 of the IC is 1.2 Ohm resistor. Can I see the picture of that R9301?
"With R9303 removed i get 9.5v on Pin 4" You mean Diode ZD9303 (15V Zener Diode) as in my post 150, if that is the case, that Zener is bad, as I said, you can leave that Zener out for now.
If you are getting 9.5 at pin 4, the output at 5.2V pin should be more than 5V and steady now then?

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

Since the thread is getting long, did you have the ZD9303 remove and have all the other components back in place to see what you will get at the output? Since when the ZD9303 is in place the FB pin voltage goes way down.

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

----All other components are back in place.----

"R9301 Shows 5.3ohms and 4.8 when pulled up" That cannot be right, Per diagram, that R9301 at pin 1 of the IC is 1.2 Ohm resistor. Can I see the picture of that R9301?
"With R9303 removed i get 9.5v on Pin 4" You mean Diode ZD9303 (15V Zener Diode) as in my post 150, if that is the case, that Zener is bad, as I said, you can leave that Zener out for now.
If you are getting 9.5 at pin 4, the output at 5.2V pin should be more than 5V and steady now then?

No i mean R9301! Sorry for the confusion. With R301 removed there are 9.5V on Pin4 and 0.33V on the 5.2V Standby pin (connector). No matter if Zeer ZD9303 is in or out...

[budm]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

I am running out of Idea right now. Have to do some more thinking.

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

When i remove pin 9+10 of T9301 there are still 1V betwenn bin 1+3 and 2 of D9308.
Where is this coming from????

[Mr_K]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

I am running out of Idea right now. Have to do some more thinking.

I have some spare time again. So budm, have you done some thinking?

I tried to supply 5v from an external PSU. I made a cut after D9308 and added 5.2V. Still the PSU is not working.

Lets assume there is another problem on the board.
What are the IC 9801 and 9101 doing. Would be nice if anyone can explain this.

Thank you and happy sunday

[mr2013e]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

i think when you are search the fault at this stand by power section, you created new fault.as remove pin 9+10 of T9301.

[mr2013e]

Re: Faulty Philips PSU (715g5246-p01-000-002s )

i think when you are search the fault at this stand by power section, you created new fault.as remove pin 9+10 of T9301.

newer remove smps output as diode.