This was more than a tear down. Nice work! The best part of your video I liked was the last 2 minutes covering the EMI filter. Brilliant. I need to build something like that filter.
Those power supplies going over the conducted emission limit with cables attached is not unusual. Test reports for some power supplies show that radiated emission has been tested with 10 cm long cables attached to the output. Some of their power supplies even have the those filters you mounted externally but those components are not populated. Thanks for the tear down. Always interesting see how those things work. The strange is thing is the PWM controller with a duty cycle limit adjustable from 60...90% for each channel while a forward converter can not operate with duty cycles > 50%. I don't see any means to shorten the off-time by for example clamps to increase the primary voltage during the off-time.
Excellent teardown and analysis! I have the 3KW version that I was going to use with my LDMOS amp, but since the fan speed varies with the current draw, and that is proportional to the transmitted modulation, the ever changing fan speed became too annoying, so I abandoned the supply for another.
you could disconnect the fan, add fan simulator pulses to the psu, and feed the fan another stable supply, and this way fix the odd fan speed regulation
Nice video, however the output of T1 is wrong I believe, it should look like T2 and the starts of the output windings should be linked together (dot indicates the start of the windings). Or to correct, just place the dot on the output in T1 to the bottom to indicate that is the start of the winding. Having a push pull on the secondary will make it an inverter and blow the electrolytic capacitors. It is an interleaved forward converter, one fills in the dead time of the other.
there is a high change of you beeing correct there, i have now been thru my notes, while both transformers are identical, one side forward fets are placed mirrorered
Hej Thomas, super god video! Jeg har en strømforsyning magen til der lyser rød i dioden og fan-speed på 100% også uden load. Har du måske en idé til hvad fejlen kan være og om den kan fikses? 😊 vh
thanks for your comment, no ! that other unit was too dead to be saved, sometimes you need to think : if time and money put into it, is worth it ? a brand new one is not that expensive, and just too many parts was blown up..
Strange , my question here exposed was dissappeared very fast, I do have the name of the PFC driverchip, so sorry to experience this. I am working on such a smps now.
@@TeardownOZ2CPU The drive smd chips for the PFC are 75A 27322 numbered (magnified founded only), the secundary windings at the end stage-> the plus wires are the black ones, the phase of the secundary upper coil need to be reversed (the middle pointed is the + line), cheers, Luc
@@TeardownOZ2CPU Thomas can you give me the path of the current at the final synchronous rectifier trough coils and elco's and fets? Thanks, it is very confusing.
@@TeardownOZ2CPU ok , it is a rarely design, I search after design articles about these item but nothing as seen as here used, thanks for the post and work.
Hi tanx a lot for your good description.i have a question a bout ZTE zxd030 s480. I have 290volte on Filter capacitors.i have no vcc voltage for 2pcs01.no short dieod on auxiliary supply.i have 12v for vcc ice2a2 and 1.4 v feedback.i don't know why soft start not working.i check isenc is connected to ground.pls help me
i dont have schematics of any meanwell unit, but i suggest you look up the datasheets for the IC's arround your problem, the demo setup in the datasheet will give you a good clue about what is supposed to happen
