Phillips 520FL3603D/F7 Power Supply Dead

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Hello newbie in this forum.

I got a question if anyone knows ? What is the value of ZD905 which is used around the circuitry of IC 3BS03 ? Is it 9.1v or 6.2V. I found a zener at this location which is short circuited. DMM reads short circuit both ways.

Also the 1Ω Resistor R929 is a bit dodgy... Its a bit deformed.

Fuse F2 is short circuit i.e is not open therefore from your descriptions in this thread the chip does not seem to be the problem.

Any help will be appreciated. Happy New Year

Kind regards

[nomoresonys]

Re: Phillips 520FL3603D/F7 Power Supply Dead

look at the zener, what is the tiny writing on it?

[nomoresonys]

Re: Phillips 520FL3603D/F7 Power Supply Dead

a zener will give a short/continuity reading if there something else involved, like a resistor for instance, one way to know is lift a leg of the zener and recheck it out of circuit.

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

a zener will give a short/continuity reading if there something else involved, like a resistor for instance, one way to know is lift a leg of the zener and recheck it out of circuit.

Hi and many thanks for such quick replies.

Ok.. The zener Diode is of smd type and its super miniature. I know its zener, cause its sitting in position referred to as ZD905 (ZD=Zener Diode).

I took it to a friends microscope (cause I don't currently have one after your suggestion) and there are no tiny letters on it, except from two Grey stripes,

The Diode either in reverse polarity or FWD biased polarity it reads short-circuit and DMM beeps while testing it in Diode mode. By that I assume its short circuited.

The FET Q905 (P3NK90ZFP) does not seem to be short circuited although it was mentioned in this thread to give it a measurement test. So by that and the writings in this thread, the IC should be fine.

All of my component measurements for Zener and FET were carried with components out of PCB.

My question is whether someone who messed with such a board, actually measured voltages around / across this zener. So from that I will be able to purchase one and solder it back.

** If that ZD905 has to do with VCC pin of the particular IC, further to the PDF of this Chip, "VCC should be in the range of 10.5v and 26v." A lot of zeners to purchase



PDF here-->https://cdn.badcaps-static.com/pdfs/...bdff0f54f8.pdf

Thank you very much for your quick responses.

I think these groups provide excellent feedback to users around the world.

[nomoresonys]

Re: Phillips 520FL3603D/F7 Power Supply Dead

so no identifiers and no schematic, yeah guess you need to trace the zener to the other components, I think alldatasheet usually gives an example circuit like for the IC's and such.

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

so no identifiers and no schematic, yeah guess you need to trace the zener to the other components, I think alldatasheet usually gives an example circuit like for the IC's and such.

Good morning. Yeah, unfortunately no schematics. If anyone has one to download or purchase let me know. !

But the Phillips manual I found has everything in schematics except the power supply. All other PCBs and Circuit diagrams more or less are in that manual. Bummer !

[R_J]

Re: Phillips 520FL3603D/F7 Power Supply Dead

What is the reading across ZD905 IN DIODE TEST?
The information I have suggests ZD905 is a 7.5v zener diode, so just check the voltage across it to see if it is zenering at the correct voltage

What is the problem with your power supply?

[lotas]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Approximate circuit from Philips

[lotas]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Here's another

[R_J]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Those are both the wrong circuit, on the DPS-411AP-1, ZD905 is located off R910 which is in series with R915,R914 which connect to the neutral of the ac line input

[lotas]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Hi and many thanks for such quick replies.

Ok.. The zener Diode is of smd type and its super miniature. I know its zener, cause its sitting in position referred to as ZD905 (ZD=Zener Diode).




** If that ZD905 has to do with VCC pin of the particular IC, further to the PDF of this Chip, "VCC should be in the range of 10.5v and 26v." A lot of zeners to purchase




I think these groups provide excellent feedback to users around the world.

Here they write that he (ZD) is in the VCC circuit of this IC.

[R_J]

Re: Phillips 520FL3603D/F7 Power Supply Dead

The Zener diode on the VCC line of IC901 is ZD902, across C911. ZD902=20v

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

What is the reading across ZD905 IN DIODE TEST?
The information I have suggests ZD905 is a 7.5v zener diode, so just check the voltage across it to see if it is zenering at the correct voltage

What is the problem with your power supply?

Hello many thanks for help. Well the diode reads 0.0001v and beeps either ways I place the test leads around it. I.e reversing polarity on it.
Ok 7.5v Zener diode I will check and place one

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Those are both the wrong circuit, on the DPS-411AP-1, ZD905 is located off R910 which is in series with R915,R914 which connect to the neutral of the ac line input

Correct RJ. However it seems that the 1Ω Resistor in place R929 is a bit deformed and it reads 2.1 Ohms. Brown black Gold Gold ! Surely that will need to be replaced and try a zener 7.5v from info that was given in this thread.

Thanks much

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Approximate circuit from Philips

Your schematics resemble the de-ciphering I did on my Board.. Lets se if its exactly the same though. Thanks for posting

[yokoono]

Re: Phillips 520FL3603D/F7 Power Supply Dead

In most cases it is a 15v zenner. It is placed for the protection of the integrated controller. Most of the time, however, when the diode is shorted, the integrated circuit is also compromised.

[nomoresonys]

Re: Phillips 520FL3603D/F7 Power Supply Dead

In most cases it is a 15v zenner. It is placed for the protection of the integrated controller. Most of the time, however, when the diode is shorted, the integrated circuit is also compromised.

makes sense to me, think I would replace the integrated circuit too.

[karatzdi]

Re: Phillips 520FL3603D/F7 Power Supply Dead





As promised I reversed engineer a bit the circuit around IC901 so as to eliminate the relation of ZD905 to the IC.

The help of the users Iotas and RJ were great. Basically the circuit is the same with a few differences which I post in my own drawing. Look closely so you can see the differences noted with either a (?) or any other notes I left on the paper. Last 2 posts from Yokoono and nomoresonys stated that ZD is usually 15v and is there to protect the IC901. However if the ZD went bad, then the IC is compromised. So I guess I need to wait until 5/23 when Mouser will be stocking this Chip. For those interested I am located in EU, Cyprus. Sorry you will ned to rotate the attachment

Heres my diagram..

Any feedback let me have it

[lotas]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Now it is clear that the positional numbers of the components do not match.

[R_J]

Re: Phillips 520FL3603D/F7 Power Supply Dead

Correct RJ. However it seems that the 1Ω Resistor in place R929 is a bit deformed and it reads 2.1 Ohms. Brown black Gold Gold ! Surely that will need to be replaced and try a zener 7.5v from info that was given in this thread.

Thanks much

WHAT IS WRONG WITH THE POWER SUPPLY??
Have you checked ANY voltages ?

The resistor is ok, you are also measuring your meter lead resistance when checking the resistor. R929 is not critical it is used like a fuse, so if it does not check OPEN, it is good.

This is the standby circuit, is it working or not? Do you have standby voltage or not?
What is the voltage measured ACROSS C911, VCC Voltage