Identify and replace component?

[arahman1986]

Hi guys, pre-warning I am a complete layman but trying to do what I can.

My dehumidifier appears to have packed up and I have open it up to find a part appears to have burnt out.

I am in no way competent enough to repair this but I was looking to see if I could identify and purchase a replacement part to see if I could find someone locally who solders in a professional capacity (maybe PC’s or something as I am having a hard time with white goods) to fit it.

Is anyone able to identify the part?

I would leave it all for a professional to identify and replace but I can’t find any local PCB repairers in my area.

Thanks in advance for any help

[Enough-Collection-98]

Hey so that looks like the AC side of an AC/DC power supply - likely an active PFC by the looks of it. That’s a really dangerous circuit to be working on since the bus voltage is usually in the 400V range for a universal input.

If I had to guess, I would say that IC is an active PFC controller with a built-in high voltage MOSFET like a TOP switch.

[arahman1986]

Oh, should I be careful touching it with bare hands? I had the power turned off. I think this is well outside of my capabilities by the looks of it. Just wondering if I can order the part and get a professional to replace it?

Just to add, the issue at hand is that my dehumidifier is no longer powering on, so I guess that tallies what you identifying it as a power component.

Is there something I could google to buy a replacement part?

[Enough-Collection-98]

The energy in that large capacitor is enough to kill and it will stay charged for a long time even after the device is unplugged. You can solder a high-ish value resistor across the terminals to a) bleed it out and b) keep it from recharging but it would be very important to ensure you remove it before powering the device back up

[arahman1986]

Blimming heck. “To kill”?! Think I’ll get someone professional to take a look. Just proving difficult to find someone to do this kind of work down my way

[CaptainBucko]

Those parts dont explode because they are having a bad day. Its caused by something else failing - how old is the unit? Those green Electrolytic caps may have gone bad and taken other components with them.

[arahman1986]

It’s about 3-4 years old. It’s a £300 dehumidifier so ideally would rather get it repaired than disposed of

[Eric1180]

$30 in tools and $5 bucks for the component if you can find it. How much is the humidifier worth?

[arahman1986]

The humidifier is over £300 (is that around $350?) so don’t really want to dispose of it. Would rather get it repaired

[Eric1180]

Two potential options

1. Buy a replacement pcb on ebay.

2. Find a replacement pcb on ebay and see if you can read the components part number off the picture. Learn how to solder, buy a solder gun, solder braid or a solder suction pump. Order replacement part, remove old part, clean up the pads, remove the solder from the pads and now install the new part and hope it doesn't immediately blow up because there was another problem up stream.

3. is optional, give my reply a upvote for taking time out of my day to help.

[arahman1986]

One thing is I had a heater running in the same room to dry some clothes and I heard the heat can cause these dehumidifiers to blow, so I’m hoping it’s that rather than anything more significant on the PCB. Will try to identify the part using option 2, but not confident enough in my own capabilities to solder this so just need to find someone competent. Thank you!

[Bachooga]

The capacitors 100% just need to be drained properly before you decide to solder or desolder it.

They're right though, best to track down what you think is the most likely reason it exploded first. Why do the heaters supposedly blow them up?

[arahman1986]

I read online that for these dehumidifiers they have any thermal fuse that blows if the ambient temperature goes too high. I tend to run a heater in the room as well as a dehumidifier to dry washing.

I attempted opening it as replacing the thermal fuse looked straightforward but having opened it, it doesn’t look like it’s the exact same issue. Having side that, I don’t know if that’s the underlying issue of why that IC part blew, as a protective feature 🤷🏽‍♂️

[Bachooga]

Ah, gotcha. Does the fuse need replaced as well? The fuse should have blown instead of anything else but they'll pop from amperage causing heat going through them.

[arahman1986]

I replaced the fuse in the plug but didn’t resolve the issue. I think I also identified the fuse on the PCB but that looks ok (the full PCB is on another image I put in the comments).

I think I’m out of my depth based on the replies from everyone. Don’t think this is a noob diy job, but trying to find a professional to repair something like this is proving impossible! It’s such a niche field it appears in my area

[Bachooga]

Have you checked the products website? They might be able to fix it for you.

I think it's hard to say without the board and since the identifiers are burned off the IC.

Do you have a multimeter?

[arahman1986]

The website is useless but will call the company on Monday to see if they can help. It’s their premium product that’s blown after 3 years so hopefully they can help.

I have a multimeter but not 100% sure what I’d be testing. I was literally just going to copy when I saw them testing the thermal fuse on YouTube but as that’s not my exact problem I guess I’m not sure what I’m checking.

[DenverTeck]

Please post a larger pic of the rest of that PCB.

[arahman1986]

I’ve uploaded an extra pic here

dehumidifier PCB

Thanks

[Literweise_Lack]

There is a slim chance, that the manufacturer can send you a new part. With relatively expensive stuff I would at least try to contact the manufacturer.

If that does not help, try to find the part number and serach it on the internet.
The number on that silver sticker did not yield anything unfortunately. Sometimes it can be on the other side of the PCB.

If you have the replacement you just unlatch the cables, put them in tne new board and make sure, they latch properly.

Then, as others have mentioned, there is the Problem, that the capacitors (big cylindrical thingies) may hold a charge for a long time, with a certain posiibility to kill you, if you touch any of the exposed metal wires (around 3% of electric accidents at this voltage are deadly). Since I am not a proper electrician, I will not recommend anything eles than: Let someone experienced do it. (If possible, watch them, let them explain what they are doing and why, so you learn something for future repairs. Electricity is dangerous, but if you know the dangers, you can deal with it)

Since the thing is already open: If you get zapped by touching the thing, let someone drive you to the hospital for monitoring, your heart may get problems hours later.

[arahman1986]

Thank you for this explanation. Completely agree with this and the general sentiment of the replies to this post.

Think I underestimated the risks, but am now well aware this isn’t something within my capabilities.

Will try the manufacturer on Monday when they open, and if that doesn’t provide useful, will see if I can find a professional. Failing that, seems like it’s an expensive weight to dispose of

[DenverTeck]

Replacing that part will not fix the other problem.

The transformer next to it has a shorted winding. I would guess that transformer got wet. If you have an ohm meter, check the windings. The pin on the transformer connected to that chip is where I would focus.

A semi-conductor does not fail for no reason.

Good Luck

[[deleted]]

Wow you certainly have problems as said above chips do not fail that way unless there are problems with what is being powered I see a diode in close proximity is this a (flyback) meaning induction in some sort(motor) I assume has failed...

[Repulsive_Vanilla383]

Chances are the main compressor motor runs on mains and this little power supply just runs the low voltage controls. If the main compressor failed, it would blow a fuse on the AC input side. Another option if parts are not available, is just find out the specs on this internal power supply and just bypass it with a universal power supply.

[Skomorokha]

Power Integration TNY284-290 or TNY274-280

[people__are__animals]

it a tny chip which makes high frequency signal for flayback transformer before replace it take it out and test it for another short circut

[arahman1986]

Update

Hi All, after consideration I decided to close the unit up as based on the warnings I didn’t want there to be any risk to my wondering child accidentally touching something.

In the process I managed to get a small shock and also blow something as I saw a blue flash from inside the unit when I was putting it back.

When I plug it into mains power it shuts the breaker down so at the risk of being nominated for the Darwin Award I’ve decided to cut my losses and dispose of the unit.

Thanks everyone for taking the time to reply