Oscilloscope Philips PM3052 Power Supply problem - Page 1
Forum section: electronics / beginners

author: aat
author_rank: Newbie
timestamp: May 17, 2021, 03:12:41 pm
content: Hello everybody,I just got my first oscilloscope!I was told that it is defect and will not power on.So I opened it and checked the power supply.This is how it looked:It is obvious that some of the capacitors might have leaked.I read the treads here and thought that it might be the notorious Rifa, but I think this Rifa is ok. Actually, I removed C6001,6002, 6006, 6005 6003 and 6004 and they are not shorted. I think the leak came from either 6002 or 6006.C6005 also looks strange...My plan is to replace all of them (even though some might be ok, the oscilloscope might go without some, etc).I was just wondering should I replace also C6007 and 6008 - they look melted:What voltage are they? - 68 uF/385v?Are there any other parts I should check?Thanks in advance for any support!!!PSI am using the schematic for PM3055, I couldn't find one for 3052

author: aat
author_rank: Newbie
timestamp: May 30, 2021, 09:10:53 pm
content: Hello,Anyone? Can someone please help?Thanks!

author: jmelson
author_rank: Super Contributor
timestamp: May 30, 2021, 10:32:40 pm
content: It looks like you have had a fire in there! Possibly the grey rectangular Philips capacitor spewed fire against the big blue electrolytics.Jon

author: aat
author_rank: Newbie
timestamp: May 31, 2021, 03:35:20 pm
content: Hello Jon,Thanks for the reply!Do you think that I should rework the whole part of the board? Or just C6001 to C6006 (the small film caps)?

author: giacomo
author_rank: Regular Contributor
timestamp: May 31, 2021, 04:16:31 pm
content: Quote from: aat on May 31, 2021, 03:35:20 pmWhat tools do you have available ?I would proced to clean the board with ipa, then should be apparent what components are exploded.The rectangular capacitors are probably part of the emi filter, the problem may just be those.You can go with your multimeter to check for shorts or open circuit around.Take also a look at those 68uF capacitors, even if you do not have a lcr meter try to measure those with your multimeer to get some hints. If the capacitance is too high or low, if the resistance stabilized in the ohms/kohms range, or if they are open/shorted.Check also the diodes, that require no time and they may have failed along with other components.

author: aat
author_rank: Newbie
timestamp: June 03, 2021, 10:25:08 am
content: Hello Giacomo and thanks for the reply!This is very helpful!I will check the 68uF capacitors and the diodes.I will also examine for shorts.Will come back with the results.Have a nice day!

author: Old Printer
author_rank: Frequent Contributor
timestamp: June 03, 2021, 03:35:58 pm
content: The service manual is available here:http://www.jetecnet.com/You may be able to find it for free somewhere, but for $15 its a nonissue. That blue cap looks like it was punched with a screwdriver blade, that is odd. Anyway, a decent service manual is worth it's weight in gold, you are lucky it is available.On second look, both caps have the same mark so maybe it is a manufacturing thing and usually covered by the shrink tubing.

author: aat
author_rank: Newbie
timestamp: June 04, 2021, 10:10:08 pm
content: Thanks OP for the info!