Flir Inframetrics PM295 Power Supply Board Issues Help Needed   - Page 1
Forum section: electronics / repair

author: NuBCracker
author_rank: Newbie
timestamp: November 07, 2017, 10:45:18 pm
content: Hi,OK Here is the problem it has. When you go to power up the camera,with the cover off looking down on the bottom board there is a Red/Green multi color led,when power first is turned on the green led light blinks for apx 100 ms then goes to red for about 2 full seconds,then from red to off,the view finder screen gets bright white when first turned on then shows lines real quick like power was removed then goes to a dim dull white blank screen.So i Looked over the board to see the chips and to get a somewhat of a idea how it works since no schematics available,Looks to be a SMPS (Switch Mode Power Supply)Design and started to check the basic components that make up that circuit which is a LM3524D(PWM Modulator) then it drives the Max4427(1.5a Mosfet Driver) then they drive the gates of the SI9410 and SI9435 Mosfets,all seemed ok to datasheet output pins,I tried to check the SI9410 and SI9435 to see if they were shorted,but all seemed OK,On the built in Diode some were .500mv tested in circuit and some .150mv ,so i moved on to the output caps to test for voltages for all the different voltages the camera has,So Output caps all had voltage except one, the C71 cap the positive side didn't have any voltage on it and was at almost ground resistance,So I reset the camera Hooked up the DMM leads on the cap + and - , powered on the camera and Voltage started to climb to about 1.1vdc,stops when led shuts off red then goes quickly down close to zero then goes to a short circuit after that.So then if i remove the battery the short goes away ,since i guess there is no return path from the battery to short to.So with the battery out i started testing everything that i could think of that the circuit was connected to but cant find a short when its not powered on,But if I unplug the battery and re install it , start testing with out turning it on,there is no short on the C71 Positive pin and didn't find any other components close by shorted out to ground,there were a bunch of voltages on the Boards output filter caps,+5v,+7v,the Shorted Cap,-5v,+10v,+12v,+5v,+5v,+5v,+6.133v,Input Battery Cap was +6.3v,by the similar voltages on those caps I think they might be using the caps hooked up parallel as the caps are rated the exact same as the ones which match the voltage that are close,but they are not right next to each other as i would of thought.Next thing I found was if I switch the power slider to the Play position,the camera does different things,a 1 Ohm resister gets very hot after a few seconds and the battery voltage goes way down like there's a obvious load on it with the resister getting pretty hot at that value,I noticed it by putting my hand flat on the board to check for any other parts getting hot,and in that position the voltages on some of the others shut off,since they probably not needed in that mode I guess, but C71 still same way.I didn't want to just start replacing all components on board,as I would like to find the actual problem part or parts.Anyone that has a understanding of SMPS if you could help to tell me what to look for next ,would be greatly appreciatedInframetrics PM295https://drive.google.com/file/d/1kBHHKWzQKJgGoZQSmMoftj1dfIZ_usHvAQ/view?usp=sharinghttps://drive.google.com/file/d/15uvw_XB5lhF3yzPWGNAFKRLFlONjOyCcJA/view?usp=sharinghttps://drive.google.com/file/d/1w_ql_TfYYbuFY2t2yy0eCvqGC2xSvGpgyQ/view?usp=sharinghttps://drive.google.com/file/d/1Vj10pZ0YvevtDHKqUUIp7z69YDgcTDIdEA/view?usp=sharinghttps://drive.google.com/file/d/1f_R40YIzMxcXamlxifOBO7200Nby5sgGTQ/view?usp=sharinghttps://drive.google.com/file/d/1TWCkeP954kFu2a1_4ilC79FDonLzWPhskg/view?usp=sharinghttps://drive.google.com/file/d/1bJfaPiEVYBwJMacnIVbvg1tSQrdkiVSZ1w/view?usp=sharinghttps://drive.google.com/file/d/1j-mer5UhE_NRGwDO3qgdPRfzwGDanWU_Wg/view?usp=sharinghttps://drive.google.com/file/d/1bJfaPiEVYBwJMacnIVbvg1tSQrdkiVSZ1w/view?usp=sharinghttps://drive.google.com/file/d/12Q7SnLn4ORR8IKQu3bi0qu2FzMKxhVRteA/view?usp=sharinghttps://drive.google.com/file/d/1zMyKbD9x6iPAjte6APHX7OseaEDai2hJ1g/view?usp=sharinghttps://drive.google.com/file/d/1Dps9BghzNa8bKM_EA_j1dgSHtXUlqzBKfQ/view?usp=sharinghttps://drive.google.com/file/d/16GD29wfIHS_8NCALfrc6E3u-eBfszkEfhQ/view?usp=sharinghttps://drive.google.com/file/d/1igrXaEUYFUI_VqmaadoTrDiqoRk_50V90A/view?usp=sharinghttps://drive.google.com/file/d/1QHa0Z3wUPJ6mq-BkYh8yhhdRS3uZYEeenQ/view?usp=sharinghttps://drive.google.com/file/d/1kMBDWFQ6yYcq7QHEVwGn755wZHRjv_689w/view?usp=sharingThanks ErikNuBCracker