Failed Lucci Constant Current LED Driver Teardown

[@jameslmorehead]

That silicon potting is Sylgard 100 series, probably 160 by how it's peeling. It's thermally conductive and electrically insinuative. We use it at my work for potting PCBs for down hole oil well drilling measurement equipment.

[@stanburton6224]

That looks like one of GE's potting compound. It is filled with thermally conductive ceramic, so as silicone goes it is MORE conductive than pure silicone, but that is a low bar.

[@austfox2170]

I had 3 x Lucci branded electronic ballasts (for circular fluro tubes) fail within the first 12 months, out of 7 installed lights. Changed them to Philips branded ballasts and they are still going strong after 5+ years.

[@jaro6985]

Its thermally conductive silicone potting compound, many companies make it. Same grey color as LORD SC-309 which is 1W/mk. Not great but better than air. You can see the second board got toasted, the potting likely would have spread the heat enough to avoid this. In the west this stuff is expensive, unsure of the price in China. "Thermally Conductive Silicone Encapsulant are filled silicone potting materials with progressively higher thermal conductivities of 0.7, 1.0, 3.0, and 4.0 W/m∙K, respectively. These materials are currently being used in numerous applications to protect sensitive electronic components from excess heat, including LED driver electronics, on-board chargers and inverters for electric vehicles, and electric motor stators. "

[@itinerantAlien]

Here you go Dave (with Australian Approvals too so if your house burns down there's one less excuse for the Insurance company not to pay out): MEAN WELL LCM-25 25 WATT CONSTANT CURRENT DIMMABLE LED DRIVER. Current is selectable by DIP switch; Multiple dimming methods; and the means to sync the dimming level across multiple units. I've used them in a number of my projects and they've always worked exactly as expected.

[@IanScottJohnston]

That 2nd unit was running HOT......the Pcb is baked in parts.

[@ShinyMajor]

If I had to guess, these are probably high power factor flybacks. The short version is they take the usual boost converter active PFC and replace the boost inductor with a flyback transformer. It has the advantage that you only need bulk filtering on the output.

[@Felipe2077tv]

Would love to see a repair video of these! Repair videos on simpler electronics is amazing.

[@mrmobodies4879]

10:47 It looks to me like the resistors got hot at the edge of the board on the right where it looks a bit burnt and in the middle.

[@viperidaenz1]

That PCB colour on either side of the isolation slot looks like the primary has been getting quite toasty

[@Polaventris]

I clicked the thumbnail without paying too much attention and was surprised to hear Dave instead of Clive :D

[@cornwallonline]

Good old Farnell! Mind you, when I find something on the Farnell site, I always make a trip to their sister company CPC, as the same item is often much cheaper! A strange setup with sometimes huge price differences - although Farnell usually has a wider range of 'bits'!

[@Rooey129]

Lucci is one of the worst lighting brands around, almost as bad as your generic eBay stuff. It's got a high end Italian name but dont be fooled its a chinese company owned by beacon lighting here in Australia, they build it as cheap as possible and have beacon push it at a huge profit, I could go on for days in their design flaws (dont get me started on their weatherproofing), it costs more in time to install any Lucci product compared to its SAL counterpart and will not last.

[@johncoops6897]

Yep - SAL is shit but Beacon's rubbish is lower than low. What's amazing is that it's not sold cheap.

[@fanest_norfar]

Potting actually helps dissipate more power when you are only relying on passive airflow in tightly enclosed housings, pretty much anything is better than air...

[@yeliab814]

i RP'd input on a 40A DC/DC 24->12, 'twas kind enuff to blow board soldered blade fuses via parallel prot diode. But had to depot to get to the fuses. Potting was a sandy almost foam like mess, scraped away easy after heat soaking in oven on low. that Cmpd def rubbish for heat; must have been for water prot or to contain smoked components.

[@nilomyki]

Imagine if Cellphone boards start coming with all that goop on it - that'll suck royally for the independent repair industry.

[@CaspaB]

Some silicones used for potting can be removed by soaking the part in solvent. I use turps first, for up to 24 hours, (least aggressive to plastic components), then turps with 20% acetone, then perchlorethylene (as used in dry cleaning). Expect damage to polystyrene caps.

[@johncoops6897]

1:05 "Lucci brand, they're supposed to be reasonble quality..." ROFL Nope, they are the cheapest possible rubbish. It's a "house brand" of Beacon lighting.

[@bazrazin1]

i recently repaired a led driver, one of its smd bridge diode(must be 1kv 1A) burned out taking the 15uf/400v cap & inrush resistor with it, replaced them & it's working fine now, i feel mains components upto the switching transformer should be normal sized, there is a strong possibility of arcing due to residual flux,moisture dirt, also CC drivers provide higher v/g to leds than there normal operating v/g even though current is limited, saw one of a series led pannel blowing some of its led's and dying .

[@redtails]

8 years is good if you consider that the second box looks like it's been cooking itself

[@CaspaB]

You can tell if it's thermally conductive if you put (the back of) a warm finger on it and it feels cold.

[@Tommyinoz1971]

8 years is ok. I bought a new LED light from Bunnings for my kitchen last year, the driver failed after two months! I repaired it by replacing the CC driver with a cheap eBay one and I'm happy to report that it has been working fine for the last 9 months (cross fingers).

[@MikeB_UK]

Aww, come on Dave, surely your inner curiosity wants to check what failed in each? We all want to see a quick bit of diagnosis and component testing. Electronics School would have the answer in 5 minutes... surely that's a challenge? Any designers need to know how to make these better and fail less.

[@navadeep025]

8:15 Crusty failed electronics smell,.....haha. Can you share any links for it?

[@cesar_otoniel]

This is not SmellOvision

[@lordjaashin]

just go to river ganges and you'll find all types of smell there

[@brettfo]

Damn. I just looked up an unknown part in my parts bin that I had labeled in a bag called "useless parts". Similar part no. I think it's the Cirrus Logic CS1616 if I caught the part number correctly as like 1616FS. A reference design found in some random PDF implies the NC pins are an I2C bus. Made me wonder what's going on inside. But...wtf am I going to do with 100 of these obsolete parts anyhow? No wonder I labeled them useless.

[@AdamsLab]

On the second one, the screws on the terminal blocks look crusty, like it was in a wet environment...

[@Ra-zor]

Once again Led's showing they are not (as far as cost vs life expectance) as good as good old fashioned filament bulbs due to driver failure...

[@mikropower01]

@Dave - The second power-supply (Model "KAI-24E... "), look at the four resitors at the input, they got pretty hot and the end-caps will fail, so that the resistance will be unlimited. Simply measure the resistance of the pink resistors. In the round powersupply the resistors are still in the Gray silicone like mass?

[@hamood1234fool]

why it says short circuit protection? Shouldn't it output 500ma current when its shorted? It says constant current after-all? What am I missing? Can someone explain?

[@johncoops6897]

Yes, it outputs 500mA or whatever when shorted. That's protected, it won't blow up. What are you missing.... who knows. It's 100% obvious and simple, there's nothing to discuss. What exactly do you think need explaining?

[@hamood1234fool]

@@johncoops6897 I thought it will blow up if you short it. Thanks for your reply man

[@Land-of-reason]

When purchasing LED drivers you need to select a driver that is capable of delivering an output of say 20% greater than that demanded by the LED's. Any ideas why and is 20% sufficient. Since I have found that these always fail. The last one that I replaced I chose a factor of 100% (150w supply for 75w strip) and it is still going strong. Any views of the pro's and con's of this?

[@rocketman221projects]

These are constant current drivers. Using higher current drivers will shorten the lifespan of the LED's.

[@Land-of-reason]

@@rocketman221projects good point!

[@johncoops6897]

@@Land-of-reason - You just said "strip" which makes me think you are using LED tape. If so, then they run off Constant Voltage so the current is irrelevant to the tape and the higher the power the better the life. A 75W or even a 150W driver is a beast of a thing if it's for bare LED chips, and if that's the case then you cannot just change the current or you'll kill the chips. What kills these drivers is HEAT. To make them last never have them near the LEDs and don't cover with insulation. The factor that matters most is the Ta (maximum Ambient Temperature) printed on the enclosure, however with Chinese rubbish it may be lies anyway. You cannot even choose drivers by brand, since every manufacturer makes a vast range to cover all price points. Anyway, because you said 75W then I reckon you mean 12V power supplies, and not LED drivers. If you are really pulling 75W, that's a lot of power, and the easiest way to improving life is to split it up and have 2, 3 or even 5 separate 15W power sources. This spreads the load and the heat.

[@BradleySmith1985]

is that not potted for bathroom regulations?

[@firstlast9292]

I suspect that potting would help if anything on that board decided to start a fire.

[@HDXFH]

Aishi not ashai, those caps are shit, used in CFLs alot

[@TheAnalogKid2]

fix it!

[@EEVblog2]

Couldn't be bothered.

[@lokig8640]

@@EEVblog2 Gigabytes power supplies are exploding, few computer KZbin channels have covered it. Be nice to have a trusted electrical engineer cover it. Also comments about testing methodologies from gigabyte.

[@MrKillswitch88]

@@lokig8640 I would love to see that covered on this channel especially if he can release the smoke.

[@lokig8640]

@@MrKillswitch88 you mean he will release the magic smoke. Haha. Also alot are suspecting that it was a design issue. If a few exploded units could get sent to Dave, hard for gigabyte to argue with an electrical engineer.

[@PowerElectronic]

@@EEVblog2 I would really appreciate troubleshooting this product. I guess they all should have similar failure modes. And I haven't seen this done before, let alone, by an expert.

[@Elnufo]

lifting the lid and babbeling is a teardown nowadays? good job then lol

[@DuroLabs85]

I buy them just to tear them apart for components. :P

[@dpyles9396]

Well... that was a waste of time Dave

[@MrWarlock1984]

new way to anti repair pot ti all and pot it good. next we will see poted phones

[@blockbertus]

I would guess the potting is there to stop or reduce coil wine.

[@johncoops6897]

Unlikely - the inductors drink beer, not wine.

[@DeejayManii]

lucci is trash tier in the electrical industry.

[@johnsonlam]

Crusty failed electronic smell, I know that because I'm not young anymore.

[@DLSDKING]

Destroy it.

[@masteryoda394]

A metaphor for your own failure maybe?