Maybe at initial test through small external fuse a bunch of capacitors was connected at dc output? Regulated smps dislike additional capacitive load, feedback oscillates then. Unregulated ones just start slower , no harm, but input limiting is needed.
Now I am the last to promote SMPS but with 23.56 Euro and free shipping one can not expect that much isn't it? 😀
Maybe it is only a good thing that it is defective. Just suppose you were listening to the amplifier in a dim lit room and then BOOM.
Maybe it is only a good thing that it is defective. Just suppose you were listening to the amplifier in a dim lit room and then BOOM.
Perhaps, I got a pair of unobtainium speakers so I don't want to gamble with them.
Perhaps it is best to go the traditional way with linear power supply.
No, just the smps to the amplifier modules.
About 4x500uF in total for two channels.
I think there was a reason for this smps to blow. And to prevent future problems and learn how to deal with them properly, whose to chose and whose not, while purchasing, needs to be determined cause . I'm using unregulated smps +-45v version for probably 5 years with no issues yet. But i've made some prevention - added external inrush limit resistor 47 ohms 50w , and two ac ssr 20 ampere relays, one starts with resistor in series, another one starts later direct. No mod required from smps side.
Speaker protection is not a luxury but a definite necessity when using Aliexpress SMPS. With rare loudspeakers it should not even be debatable.
I hope the amplifier modules survived the initially directly connected defective SMPS. The lesson here is one that should not be forgotten: ALWAYS test power supplies without the official load being connected. Be either linear, SMPS, DIY or whatnot. If it needs a load then use load resistors, lamps or whatever.
You have learned a few good practical lessons here. That is positive. And for only 25 Euro!
I hope the amplifier modules survived the initially directly connected defective SMPS. The lesson here is one that should not be forgotten: ALWAYS test power supplies without the official load being connected. Be either linear, SMPS, DIY or whatnot. If it needs a load then use load resistors, lamps or whatever.
You have learned a few good practical lessons here. That is positive. And for only 25 Euro!
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It don't come cheaper than that 🙂
I have another pair if the modules didn't survive.
They are old and I got ahold of two stereo kits. I didn't plan on wasting them but at least everything is fixable.
That's not on the linked page, you can find it in the specs of a different seller. I have a different model of the SMPS. I remember that the wire ends between the board and the U-shaped alu profile were very long. I'd check that there aren't any wires touching the alu before trying anything else.
I'm sorry for not writing this before, but I stumbled up on the thread and didn't realize that could be the problem initially.
I think I messed up.
Having checked the amplifier PCBs I noticed that I have placed a resistor wrong. It was a mod suggested on a later version but I still messed up.
The result was a 0,15R 5W resistor shorting an output transistor and thus causing a massive power draw from the PSU.
So, due to high current draw the above parts blew.
Perhaps it can be saved?
Having checked the amplifier PCBs I noticed that I have placed a resistor wrong. It was a mod suggested on a later version but I still messed up.
The result was a 0,15R 5W resistor shorting an output transistor and thus causing a massive power draw from the PSU.
So, due to high current draw the above parts blew.
Perhaps it can be saved?
We are now sure you messed up 🙂 It still should have overcurrent protection but it is either lacking or not upto its task.
SMPS repair requires certain skills and it is simply shitty work to do. Buying a new one is faster, less work and likely cheaper too.
I for sure hope you never connected your rare loudspeakers to the amplifier.
SMPS repair requires certain skills and it is simply shitty work to do. Buying a new one is faster, less work and likely cheaper too.
I for sure hope you never connected your rare loudspeakers to the amplifier.
Since I got all this wonderful support, the least I can do is to tell where I messed up 🙂
No chance, they will have to be working for weeks before I try that (and have speaker protection ) 🙂
Yes ,most probably this smps had poor overcurrent protection ,only on high side , which didn't protected mosfets . You can probably repair it with help , but it can be pricey and takes long. China smps can have fake cheap parts ,remarked , and if you try to buy same marked proper parts from reputable seller like mouser , it may be up to 1/2 price of that smps . Lets say shunt resistor , mosfets , control ic ,few small resistors ,diodes .Those are typical parts ,who are taken together with mosfet .Reason - bad choice of shunt resistor, it opens when blowing ,thus 300 volts appear there ,where only 1-2V can be present at normal operation, damaging other components ,not just blowing fuse .So only mosfet replace will not work . Also frequently control ic blow nice and leaves only a hole in place of marking , then it's harder to determine what should be there .So if you have a very big interest in repair this smps ,learn some new things , you need to draw a complete schematic first ,then it will be clear whose parts are damaged and which are suspect too .Then check where to get them ( not ali* ) and how pricey is that.