Help diagnosing power supply fault in Philips DVD player - Page 1
Forum section: electronics / beginners

author: Birstall
author_rank: Contributor
timestamp: December 02, 2020, 06:36:44 pm
content: I have a cheap Philips DVP3680/F7 DVD player, I have replaced two capacitors already and the thing is down again. It will not power up.I tried Philips and had no joy getting a schematic. Nothing has shown up on Google nor can I find an FCC # to check if they have anything.Any suggestions would be most appreciated.

author: Labrat101
author_rank: Unknown
timestamp: December 02, 2020, 07:16:19 pm
content: I suggest you look in the Repair section there are many ManualsPictures are helpfulYou did not look that Hard . when searching use circuit diagram . as well ..https://www.manualslib.com/manual/1546439/Philips-Dvp3680kx.html

author: Birstall
author_rank: Contributor
timestamp: December 03, 2020, 11:48:41 pm
content: Thank you and apologize for not trying harder. I really did look a but did not use "circuit diagram" in my search. Mea culpa!

author: Labrat101
author_rank: Unknown
timestamp: December 04, 2020, 02:03:08 pm
content: Quote from: Birstall on December 03, 2020, 11:48:41 pmI hope that link will solves you problem.And get your player up and running.Good luck.

author: Birstall
author_rank: Contributor
timestamp: December 12, 2020, 07:56:28 pm
content: Well a week or two later and I am no further forward. The player will not power up.Looking at the attached circuit diagram for the power supply, I have tested the input voltage, bridge rectifying diodes, several capacitors and downstream diodes and resistors. (All out of circuit and tested ok).What I can't figure out and would really appreciate some advice on, is what voltage I should be looking for at certain points along the circuit.The only notated voltage is what looks like -12v after PD10.I know this is a cheap DVD player that I can replace for $30 but persevering with this is the experience that I need.

author: james_s
author_rank: Super Contributor
timestamp: December 12, 2020, 08:00:44 pm
content: There are two outputs, what voltage to you measure on both of those? They are linked by being part of the same transformer so if one of them has the correct voltage, the other is very likely to as well.

author: retiredfeline
author_rank: Frequent Contributor
timestamp: December 12, 2020, 08:04:47 pm
content: I think that's an underscore, not a minus. Looking at the polarities of the diodes, I'm guessing +12V. Vcc might be +5V. That TL431 in the feedback loop is a regulator. Look at the datasheet and do the maths with the feedback voltage divider and you'll get the Vcc that it's trying to regulate to.And you really need a better title for this thread.

author: Benta
author_rank: Super Contributor
timestamp: December 12, 2020, 08:32:19 pm
content: Pretty classic flyback converter using Infineon Coolset ICE3B0365J.VCC should be +5.1 V.P_12V should (duh) be +12 V.

author: IanB
author_rank: Super Contributor
timestamp: December 12, 2020, 08:35:17 pm
content: Quote from: retiredfeline on December 12, 2020, 08:04:47 pmSeconded. For example, "Help diagnosing power supply fault in Philips DVD player"

author: Birstall
author_rank: Contributor
timestamp: December 12, 2020, 09:34:08 pm
content: Thanks done that.I have checked the voltage at PD10 and it reads 13.84 VDC

author: Benta
author_rank: Super Contributor
timestamp: December 12, 2020, 10:02:38 pm
content: Quote from: Birstall on December 12, 2020, 09:34:08 pmProlly OK. It's an unregulated output anyway.More important is VCC, which should be pretty close to 5.1 V.

author: GerritMax
author_rank: Contributor
timestamp: December 12, 2020, 10:45:53 pm
content: I don't know if this file is of any use.

author: Birstall
author_rank: Contributor
timestamp: December 13, 2020, 05:48:58 pm
content: I tested the VCC pin on the CE3B0365J chip and found about 1.7 DCV.I then put the probe on the other pins for curiosities sake. I must have shorted between pins 3 and 4 with the probe and was entertained with a flash and a lump taken out of the chip.I also discovered a nearby 1.5 ohm SM resistor was also fried.I know I know but I am a beginner and that's the way I will learn eh?Unfortunately I don't know if I have found the problem or created another. The fuse is intact as are the traces around my accident.Whadya think give up or belly up to the bar?

author: Benta
author_rank: Super Contributor
timestamp: December 13, 2020, 06:46:17 pm
content: Give it up. The IC's dead, and who knows what else.A tip: as a beginner, don't start with probing around on the high voltage/mains side. You've seen the effect on the circuit, and the effects on you might be much worse.

author: Birstall
author_rank: Contributor
timestamp: December 13, 2020, 07:06:28 pm
content: Quote from: Benta on December 13, 2020, 06:46:17 pmI appreciate the advice.I have an isolation transformer. I sat on my left hand before poking around with the DMM probe so safety wise I think I was being careful.

author: james_s
author_rank: Super Contributor
timestamp: December 13, 2020, 07:50:52 pm
content: Well it's a ridiculously simple power supply so if the IC is still available it wouldn't be too hard to fix. It sounds like it was working before you started poking around in it though which suggests the fault is somewhere in the rest of the DVD player in which case there is not much point in repairing the power supply unless you just want a challenge.

author: Benta
author_rank: Super Contributor
timestamp: December 13, 2020, 09:11:09 pm
content: Quote from: Birstall on December 13, 2020, 07:06:28 pmThat's better than beginner, don't undersell yourself.