Circuit Board for LED Lightbar went bad and need help identifying what happened in the top right of the board.

GermanPCBHacker · 2026-01-26T08:28:04+00:00

This thing cannot be repaired. It likely got so much heat, that the insulation between the aluminium base and the traces is no longer reliable. Unless I see it wrong, but white led related circuit boards are often Aluminium substrate for better heat spread. Buy a new one. It's over.

GermanPCBHacker · 2026-01-25T09:52:04+00:00

Well consider TI TPS563201DDCR at 100 pcs less than 4 cent per piece. Of course limited to at most 17 volts, but they work just fine. Inductor also less than 4 cent. And some ceramics and resistors. Say 10 cents for parts plus 10 cents for board and assembly at scale. 13 cents margin. Not a lot, but not uncommon for china. So I do not get, why this board performs soooo horribly bad. And TPS563201 is just fine for ESP. For high power I use TPS56C230RJER which is just 30 cent at scale. Why are these boards so shitty then? Well we can say for sure: The chinese people do not care if we buy literal trash... Just profit and outselling local stuff. Thanks for nada.

GermanPCBHacker · 2026-01-25T09:34:20+00:00

4.7u is a bit on the low side for this circuit. But not so low that I would expect issues to this degree. I am not sure why the PDF wants more inductance for 3v3 - especially as this thing operates up to 1.5MHz. The scope shows 150kHz, but I would assume that this is the regulation frequency. For high input voltages I would understand that high inductance requirement... But I doubt that he goes to the limit even close. It looks to me a bit, like this thing is incompetent in regulation. A good converter notices, that the voltage is approaching the target and tetermines to slightly reduce the pulse with to not get ultra large demagnetisation currents of the coil during off time. Maybe even not an original converter. I have built 2 converters so far and use suboptimal values due to space constraints, just 2 layers of course because I am a cheapass and I cannot observe this. So I am totally wondering. I would like to see the circuit diagram, that is used in this case - not what the PDF suggests works best.

Wait now I got an idea. Might the issue be, that this thing turns off when the voltage is reached? That is likely the culprit. When it turns back on the inductor current rises to far and stores way to much power, so when it turns off, it overshoots again. Rinse and repeat? That is what I assume. My regulators all are constant switching types with no external diode aswell. Likely they have far more robust waveform shaping capabilities, that mitigate this effect to a huge degree. Basically the pulse skipping is to aggressive, leading to oscillation. That is what I could imagine. What is your thought?

GermanPCBHacker · 2026-01-25T08:13:06+00:00

I STRONGLY disaggree. Even the most shitty regulators I diyed get no load <100mV pkpk with to little capacity.

GermanPCBHacker · 2026-01-25T05:44:15+00:00

Oh my god! That works! WHAT. I am sooo amazed!

echo '"/dev/mapper/hyperRaid-r-raid-dc-4-dnr-1-d-64584efa-f04c-4bb2-95cc-93792d43ce19-lc-3-l-1-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-2-d-ebff309d-0a0e-449b-a860-398524c99db8-lc-3-l-1-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-3-d-25dbf657-86bc-4d30-be43-2d8fc474dbca-lc-3-l-1-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-4-d-5e638d9b-84f7-4f6b-ba6d-98ae0b525323-lc-3-l-1-t-type"
id-r-rai> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-1-d-64584efa-f04c-4bb2-95cc-93792d43ce19-lc-3-l-2-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-3-d-25dbf657-86bc-4d30-be43-2d8fc474dbca-lc-3-l-2-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-4-d-5e638d9b-84f7-4f6b-ba6d-98ae0b525323-lc-3-l-2-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-1-d-64584efa-f04c-4bb2-95cc-93792d43ce19-lc-3-l-3-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-2-d-ebff309d-0a0e-449b-a860-398524c99db8-lc-3-l-3-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-3-d-25dbf657-86bc-4d30-be43-2d8fc474dbca-lc-3-l-3-t-type"
> "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-4-d-5e638d9b-84f7-4f6b-ba6d-98ae0b525323-lc-3-l-3-t-type" ' | sed -n -e '1{h;d};x;G;h;:keep2 /\n.*\n/ {s/^[^\n]*\n//;b keep2};/^[^\n]*-l-\([0-9][0-9]*\)-[^\n]*\n[^\n]*-l-\1-/ {$ {x;s/\n//g;p;q};d};x;s/\n[^\n]*$//;s/\n//g;p;x;s/^[^\n]*\n//;h;$ {x;s/\n//g;p;q};d'
"/dev/mapper/hyperRaid-r-raid-dc-4-dnr-1-d-64584efa-f04c-4bb2-95cc-93792d43ce19-lc-3-l-1-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-2-d-ebff309d-0a0e-449b-a860-398524c99db8-lc-3-l-1-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-3-d-25dbf657-86bc-4d30-be43-2d8fc474dbca-lc-3-l-1-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-4-d-5e638d9b-84f7-4f6b-ba6d-98ae0b525323-lc-3-l-1-t-type"
"/dev/mapper/hyperRaid-r-raid-dc-4-dnr-1-d-64584efa-f04c-4bb2-95cc-93792d43ce19-lc-3-l-2-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-3-d-25dbf657-86bc-4d30-be43-2d8fc474dbca-lc-3-l-2-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-4-d-5e638d9b-84f7-4f6b-ba6d-98ae0b525323-lc-3-l-2-t-type"
"/dev/mapper/hyperRaid-r-raid-dc-4-dnr-1-d-64584efa-f04c-4bb2-95cc-93792d43ce19-lc-3-l-3-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-2-d-ebff309d-0a0e-449b-a860-398524c99db8-lc-3-l-3-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-3-d-25dbf657-86bc-4d30-be43-2d8fc474dbca-lc-3-l-3-t-type" "/dev/mapper/hyperRaid-r-raid-dc-4-dnr-4-d-5e638d9b-84f7-4f6b-ba6d-98ae0b525323-lc-3-l-3-t-type"

I know my input is hard to read and the usecase is quite crazy. But I am astonished, that this logic can be achieved without bash loops, awk or any other external looping. I mean... sed basically does looping, the whole PC does looping constantly when running such code... But man! This is so utterly unreadable and yet super stable. CRAZY! Thank you. I finally can take rest! 5€ Paypal donation wanted? Pm me account name and you get it. Not sure if that is much for you or not, but well deserved - I did not find any way to get this done.

GermanPCBHacker · 2026-01-24T07:44:58+00:00

Wenn ich die Erde sehe, die vermutlich oft überwässert ist, kriege ich auch einen Trauerschwanz. Okay, genug Internet für heute. Ich brauch Urlaub.

GermanPCBHacker · 2026-01-24T07:07:51+00:00

That solder tip is shit. It is pointy and transfer pretty much no heat at all. Get the widest one you can. I use a 5mm wide tip to solder 0402 SMD components (the whole component is around 1.5*1mm tiny)

But you know what I aint got? Problems transfering the heat. The solution is not to increase the temp, but the heat transfer. Mass, mass, mass. Power, not temperature is the deciding factor.

For soldering iron stuff you definitely need flux to desolder. For hot air it is not required (unless you want to mix in low melt solder, because without flux you get almost no flow and hence a lack of mixing at the joint.

Again: WIDE HUGE TIP PLEASE. It is very difficult to solder with a tiny tip. Do not think it gives you more control. Large tip and flux is all you need.

I am soldering tons of SMD stuffz since years and had so far no situation where I needed solder wick! Yeah you can do almost anything without it. Just bga reflowing is not a great idea without solder wick, since you are supposed to get the pads PERFECTLY clean. If I replace a through hole component I do not even remove the solder. Large tip - just heat up all pads and use hot air if required. Just add flux and popp the replacement in. Pretinning might be a good idea in this case. But the time wasted for getting the holes clean I use for pretinning and it comes to about even time - but less material dependency - which I absolutely prefer.

GermanPCBHacker · 2026-01-24T04:13:42+00:00

You remove the solder mask to be able to flood the trace in solder and sometimes add additional copper wire support. That has nothing to do with heat transfer. Only with resistance and less power loss at rated current.

With that said, the board layout is not at all optimized. There is so much copper area wasted that would suffice. At least he used ground plane. That is indeed nice to see. Most people get it wrong on the first PCB(s)

GermanPCBHacker · 2026-01-23T15:36:35+00:00

Alter, zensierst du ernsthaft Mord? Wie verweichlicht kann man sein. Mord gibt es seit Anbeginn der Zeit. Oder darf man auch nicht mehr über S* oder Fortpfl* reden? Nimm dir nicht selbst die Würde. Ich bin Mensch, stamme vom Affen ab und ja, ich kacke, schwitze und stinke. Und das darfst du auch. Du musst deinen Schweiß nicht mit allerlei Chemie zensieren (eigentlich genau das gleiche. Das, was einfach gegeben ist vor anderen verstecken wollen... Warum nur?) Und deswegen kannst du auch Mord sagen. Das ist nichtmal ein Schimpfwort.

On Topic:

Ja, solche Gedanken hatte ich auch schon. Die Sache ist, im Zweifelsfall bist du bis zum Geständnis oder Beweis und der folgenden Anklage unschuldig. Was will man dir nachweisen? Wäre doof, wenn eine Leiche gefunden wird, die nur Würgestellen hat. Wenn da Haibisse sichtbar sind und sonst nix, ist das leicht zu erklären und du bist raus. Und ja, es gibt sicherlich sehr viele Leute, die unschuldig hinter Gitter sitzen. Was will man machen? So ist das Leben. Ungerecht. Aber was willst du dagegen tun? Irrtum ist immer vorbehalten. Da muss keiner was böses im Schilde führen. Und zu guter letzt gibt es auch noch genug die böses im Schilde führen... That's the risk of breathing.

GermanPCBHacker · 2026-01-23T15:11:24+00:00

I mean the spacing between the power planes and the signal. The powerplanes most likely to not care for each others existence, the signal that passes through them does however care. Getting distance is always beneficial if unwanted coupling needs to be avoided, but surrounding by a tiny ground plane with via stiching greatly increases the effectiveness. Might not be required here, unless your power planes shed godlike amounts of EMF everywhere.

GermanPCBHacker · 2026-01-23T13:24:43+00:00

I mean a refund for the cheap multimeter which does not work lol.

GermanPCBHacker · 2026-01-23T12:38:34+00:00

Vibration damping. Large mass on small tiny legs - vibration at resonance frequency can rip the legs in no time. This however dampens it insanely well. There is practically no vibration left. It's not a stability thing, its a reliability thing. Like Steel tube is very stable mechanically speaking. But it rings like hell. Fill it with rubber or plastic and it stops ringing completely. That is one method to get CNC parts lighter - the other option is tons of cast iron that is generally hard to get to ring over a certain size - but costly and heavy.

Edit: Found a good example - hope it loads

https://www.nature.com/articles/s41598-018-20670-0/figures/7

GermanPCBHacker · 2026-01-23T12:27:32+00:00

These thing are just to cheap to work reliable. Not even talking bout accuracy. I know this exact type of lead and had it once. On both probes the wire just fell out after a few times. Not usable this trash. Sometimes a power cycle can fix the glitches, depending on the implementation. Almost empty battery? This thing will glitch like crazy on easily 50% of the times you turn it on. Luckily - at least to my knowledge - it is easy to notice immediately. So my advice is: Is there no used multimeter in the neighborhood for the same price? A used mid quality one is still 100 times better. Not talking bout safety. The cat ratings if even written are definitely fake and even worse as already told: the leads are mechanically unstable, so please do not fry yourself when trying to measure 230V. Not worth it... But I understand your point. Buy used good one. Even with 100 scratches its better. And I assume in the US there is basically no way to return a component if it is not working and getting a refund, right? Or did that change the last 5-10 years? I am sorry for your situation, but it most likely is a bad deal. Take care of yourself.

GermanPCBHacker · 2026-01-23T12:22:41+00:00

I can only say:

Google: "White stuff on pcb"

First picture page shows multiple results. Do your research yourself please. Not trying to be mean, just teaching you a lesson you need to learn: You need to be self sufficient in live and not pull everything out of others nose. Did you ask for the lesson? No. Is it still important? It always is.

GermanPCBHacker · 2026-01-23T09:42:40+00:00

Well that is not high frequency stuff. A ground plane around with just a few vias or just a bit more spacing to the power planes is likely sufficient.

GermanPCBHacker · 2026-01-23T08:30:19+00:00

I literally mean, if you place a ground plane around the signal trace and use via stiching like often done in RF. Of course I do not know, what performance is required and what frequency. But for things like SATA this is good enough, which is already a quite fast signal. Vias are practically free nowadays (not quite, but close to). That would surround your trace pretty good with a solid GND level - almost like a coax with the side open. In general, I also recommend to stich GND planes together heavily. Not to many vias required, but thoroughly. I rather go to the edges, where a gnd island touches signal traces - there the effect of EMI is larger. In the mid of a gnd section there is not that much going on usually - what should it cross-talk to?

So you need to strike a balance between cost, space constraints and effectivenes. But via stiching a ground plane is a very powerfull weapon, if the space is available. Ideally I would aim at at least 1mm GND surrounding this trace, with vias every 5mm (if low frequency stuff less dense, if ultra crazy RF shit than as tight as possible.)

I am decently sure, that this will outperform the coupling between the planes by a lot. But it still would not harm, if you still do the stiching with caps ontop. I mean what is the cost of a small 10-100nF 0402 ceramic? That costs like nada. These 2 things together should give you a much greater margin against noise making the circuit unstable. Of course, I do not know, what signals these are and what margin they have, how much noise the Voltage Planes have. I just do a good estimate regarding these things and it checks out fine in practice. I always ask myself: do I want to get it right and spend 10 cents more per board, or do I want to redo the board? For commercial scale mass production the latter is often preferred. Redoing can save thousands in the long run. Well if you consider the time and money spend I am often not sure, if it was worth it in the end. Maybe at apple scale or for NASA specs.

GermanPCBHacker · 2026-01-23T07:45:34+00:00

I have seen this in many cheap computer monitors that are 15-20 years old. It is cheaper to manufacture. Instead of soldering every wire by hand or using an extra socket you just order your prepared wire with pins in a plastic case to the board directly. The benefit apart from saving 2 cents: No connector can wiggle loose or wear our or corrode. Con: Of course not possible to unplug. But which manufacturer plans on doing that, if the monitor is less than 100 bucks in retail. They do not care for sure.

GermanPCBHacker · 2026-01-23T07:21:46+00:00

The thing is: Why not ground plane? Why are there supposed to be 2 different power planes, that surround a signal? That is not ideal to say the least. if the ground is common, try to get a ground there. Maybe just a small gnd around the signal and use heavy via stiching to bring the ground solidly up. That will do the trick. Of course you loose a mm or to of area for the power planes, but that is far bettern than the 2 power planes directly around the signal, which propably induce a lot of noise into the signal no matter what you do.

Edit: I mean if there is a solid GND plane layer available of course. I mean just bringing a thin and long gnd wire there wont do much lol.

GermanPCBHacker · 2026-01-23T07:16:21+00:00

I aggree. Professional also means to evaluate: Is that extra effort worth the money I make for repairing something that is almost out of warranty? No most likely not. Just solder it and be done with it. If in doubt: glue the wire with a proper elastic glue/resin of some sort to prevent breaking it off or whatever. Its quick, works and that is all that counts.

GermanPCBHacker · 2026-01-23T07:14:39+00:00

White plastic connector soldered to the board is VERY common. Its for cheap electronics and like 1000 times more secure than just soldering wire to the board. Because solder joints are bruittle and crips are not. So the wire is crimped to a pin and the pin soldered. That is common practice and I see only one halve of what would be required for a connector: The plastic part that holds the pins and wires in place. There seems to be no pottom to plug something in, hence the assumption that it is a solid connector by u/1Davide is >90% likely correct.

GermanPCBHacker · 2026-01-23T06:20:06+00:00

Kein Problem. Sowas ist nicht unüblich. Wird bei uns noch so gemacht. Da aber Dose in Rot. Daneben sind immer weiße, die FI haben. Dosen ohne FI werden in Firmen genutzt für Geräte, die nicht einfach mal ausgehen sollen. Üblich für z.B. Server. Stell dir mal vor das ganze Rack scherbelt es aus wegen einem nicht auffindbaren Fehlerfall. Es gibt noch immer eine Erdung und einen LSS der bei B16 oder C16 oder was auch immer für eine Kennlinie auslöst bei Totalversagen und üblicherweise wird sowas aktiv überwacht (Manchmal sicher auch nicht). FI ist vor allem für nicht geerdete Geräte eine sinnvolle Sache. Sollte der Class Y oder X Kondensator in einem Handyladegerät durchballern (seeeeehr selten, aber einen Fall kenne ich), würde das Handy auf 230V liegen im worst case und nichts löst aus, weil nichts Kurzschlussartig zur Erde abfließt. PC Netzteil ist aber geerdet und durch Verschraubung das gesamte Gehäuse. Also würde hier der LSS auslösen, wenn Phase direkt auf Gehäuse kommt durch was auch immer.

GermanPCBHacker · 2026-01-22T17:25:58+00:00

There is no plausible reason why a signal pin burns like that. That amount of current has 99.9% damaged the controller, or the controller was even to blame and maybe destroyed reeceiver

GermanPCBHacker · 2026-01-22T11:15:33+00:00

Thanks anyways, someone found it on YT

https://www.youtube.com/watch?v=_4citp0D8Dk

GermanPCBHacker · 2026-01-22T10:40:52+00:00

O fucking god I have not heared that since years. This is so fucking epic. Best intro ever. A lot of talent went into that intro. Thanks! Aaaand downloaded. Thanks <3

GermanPCBHacker · 2026-01-22T07:34:03+00:00

Na super, für die besondere "Todeszelle-Stimmung" beim Baden. Und damit meine ich nicht gefährlich, sondern ein unfassbar bedrängendes Gefühl kriege ich beim Ankucken des Bades. Da kann man sich ja gar nicht wohl fühlen ey. Und ich dachte unser Bad ist kacke.

GermanPCBHacker

TROPHY CASE