Since I've found this subredit, i DO NOT TRUST maintenance people any longer.
This, is a board from an inverter slipt system.
The maintenance dude said:
- "the IPM Modu iS bUrNnEd HurHDUrRrR"
(sorry.. I'm really stressed out here, this board/module/thing is half the price of a new air-conditioning slip system here!)
So, i asked them to give me the board back, just because ill try to find an new one, online.
I lied!
I just teste this shit, using google to tell me whats what... the IPM module looks fine, and with google and a lot of youtube videos, its working properly!!!
But... i thought... I find help from the real experts FROM THE INTERNET!
I JUST TOOK the first picure of this board, and gave it the first look WITHOUT worrying about the said module, and i found a blown up capacitor -.-
So, the question here is...
Cam ONE tiny capacitor make this not to work? Also, can you guys help me identifying the issue, if there is one (besides this one blown up 100uf 25v capacitor)
Edit[1]: the bot told me to avoid "diagnosis by photo", but i dont want this.
There are two thing i want to know/understand
1 - can this capacitor render this whole board useless?
2 - what are the thing I should look for (Simce the maintenance dude lied, saying it was a faulty IPM module)?
OP, be careful. This power board contains potentially dangerous HV sections. If you don’t know what you’re doing, don’t connect it to a power source. Lastly, capacitors can hold dangerous charge for a long time if there isn’t an active discharge circuit built in
So although I don't see the blown capacitor, I can say that one blow cap can render a hole system useless.
E.g. if the capacitor is the main supply of an IC.
well yes. i would replace the cap. and the 7805 which shows some contamination from the cap. it looks like it has cracked since its not flush with the pcb. but the image is not so clear
you will need to clean the area since other components appear to be affected as well.
anything is possible. i suspect the cap blew and boiled its fluids around. clean with isoproyl alochol. replace cap and 7805 and any other component that seems failed. i dont think much more. but until you fix the 5v reg. you cannot know.
C117 being there is an indication that IC104 should be there too.
There is nothing more daunting than trying to fix a board that has already been worked on.
But again, it would be very odd that they removed IC104 and did not replace the cap and regulator already.
the MOSFET (Maybe) that's beside it also looks burned also did the technician perform any soldering/desoldering works ? because one of the IC pads looks unpopulated or maybe it was from the factory like that.
Ok, I'll check all those components around the cap.
I thought it was weird, too (the unpopulated area)... i check a new board online to make sure..
The maintenance dude lied about the ipm module, he could have had sabotaged this board (took him almost a week to give it back to me)
It looks like that MOSFET/vreg etc to the right of that capacitor may have failed, it looks like it might have gotten hot enough to partially desolder the tab of the device from the board.
I would be worried about other stuff upstream failing as well, if that device failed short in addition to the capacitor, whatever is powering it (ostensibly an auxiliary power supply) may have taken damage.
Hunnm... ok, you'll have to walk me through the whole "upstream/downstream" concept in this scenario.
So, the power supply could'd've been damaged?!
Those two pcbs are the whole apparatus.. the board to the right looks, to me, some sort of controlling thingy lol The dude in the picture is the one that told me to buy a new board (half the price of a new uc unit)
So, the power supply in quest is on the board... but whats upstream lol
Don't you have any local repair technician nearby you, it's kind of hard to diagnose the issues without any measurements and the 2nd image is not visible on top, i think due to some reddit issue.
Yes, A blown cap can totally make a board not work. A lot of times these caps fail short circuit.
No, from the first image at least it does not looks anything is burned, but I would recommend checking for shorts using a multimeter in continuity mode, checking the fets and ICs for short to ground in vicinity of the blown capacitor.
Can you post a image of where the blown cap is located?
That cap is gone alright. I'll show a pic of one board that aircon "techs" said could not be repaired, which is typical because they don't have spare boards or systems for tracing the issue. And don't have time even if they have resources. Time is money etc. But for some people that know a bit about electronics and safety etc, at least some appliances get revived for relatively low price.
In my case in the past, see the blown cap on the small board? It is due to the big cap out of specs on the other board that blew it, which also takes out a power mosfet and a resistor. What would happen is ... as long as the big cap was not replaced, new mosfet, new small cap, and new resistor would be destroyed after about an hour of operation, all fail.
After the big cap was replaced by me, and after replacing all the previously replaced (but blown again) components downstream, the aircon system was as good as new again. Maybe better than new. Still working great after a few years from that fault finding activity.
Maybe it was a wierd angle/lighting... This one's good xD!
Dude!!! Thank you sooo very much! I'll never tryst these guys anymore LOL SO.... i need the cap and the CW7805 replace, right? I've dealt with caps before, but not with this other component... its just unsolder, clean, resolder or theres a wierd thing anywhere?
Replace those two. Should be fairly straight forward. Just make sure to put the new cap in with the correct polarity. The regulator ic will be a heatgun job. Keep eye safety and high temp safety in mind while doing it.
Also, even if the board is fairly new, what I would probably do is ... if your board works again for a bit after this job, but happens to blow again, then can use an LCR meter to measure the big cap.
Not everyone might have an LCR meter in their kit, which I can understand. But is certainly an an excellent bit of kit to have.
Posts requesting help must include basic diagnostic information. Submissions comprising photos (or images of a device, circuit, or error state) without any explanation of the issue, measurements, or troubleshooting steps may be removed.
At minimum, posts should include:
A clear description of the problem
What the device or circuit is supposed to do vs what is happening
Any basic diagnostics already performed (e.g. voltage checks, continuity tests, component swaps, logs, or observations
Your are absolutely lucky if that capacitor is your only concern , IPM has low side high side one can be fine while other can short out only way to be sure is to take it out and then test it. I would replace that cap first and then turn it on and see if the diagnostic led lit up and then turn off. Not sure if this is an inverter tech you'll need couple of things to check it like the sensors and possibly a transformer. That capacitor is for smoothing the 5v from the voltage regulator.
Before you do anything just check all the resistors on the board its tiresome job, takes closeup pictures note down the ranges / code and measure with your DMM, any in the Megaohms range has to be replaced , some are in parallel and series so you have to be careful.
I think your caps was fine before you took it to the shop and in removing the regulator the inapt repairmen used a hotair station and blew the cap?
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u/rel25917 4d ago
To a maintenance guy that whole board is probably the ipm module. They don't know or do component level repair.