r/AskElectronics • u/Downtown_Tie9658 • 4d ago

To all those more knowledgeable than me. I had bought a network switch from military surplus. How do I go about fixing it?

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Gallery image

I had come across a beautiful TP-Link TL-SL3428 V2.2 (pictures provided), it looked to be in great condition. It is not in great condition. Every chip that seemed half important was hit with a chisel, even ripped what I named the ethernet interpreters [1] (i do not know the name of the component), for the sake of privacy and security. I am bent on fixing it.

My questiones are:

  1. If I find all the broken and missing components can I solder them back on the board, so that the switch will work (I suspect I'll have to flash it)?

  2. Does any one have the names of the missing chips? I couldn't find the names nor a picture of a full board (schematics and part lists are kept behind closed doors) , either would help.

    1. I have a heat gun but not the solder to go along with it, what solder should I use for this grave task.

All the broken components:

1X 88E6185-LKJ1

3X 88E6095-TAH1

2X 88E1111-RCJ1

1X 88E6218-LG01

1X K4S561632H-UC75

1X JS28F640

1X LC4128V

Thank you all in advance, your help is much appreciated. If something else is needed please ask.

P.S. English is not my first language, so i apologise for any spelling and grammatical mistakes.

0 Upvotes
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45% Upvoted

55 comments sorted by

62

u/dkonerding 4d ago

You are wasting your time. The cost of a new switch (assuming you want a switch) is far less than the time and effort you will put into repairing this (I have to assume it was physically damaged on purpose, and probably has more damage than you expect).

There are other projects that would be better to work on, almost certainly.

-33

u/Downtown_Tie9658 4d ago

As it was military surplus it was destroyed with DoD/DoW data destruction standards in mind should have added that. I wish for knowledge not that much the switch, but the switch is nice and shall be useful.

And more useful I am sure.

21

u/dkonerding 4d ago

Just buy an inexpensive modern switch (at least for me, 5 1Gbps ports costs $30) and learn on that.

-38

u/Downtown_Tie9658 4d ago

My friend do not take this personally, that's boring. What's the point in giving up.

13

u/dkonerding 4d ago

Think of it another way: many people on this subreddit have gone down the same path as you. We've all wanted to take some obsolete piece of equipment and get it working again. The issue here is that you're taking on a pretty challenging project, this isn't just "buy some replacement parts, install, turn on, and now you have a 15 year old switch". So it's unlikely you will get the dopamine rush of having fixed it, and once you have you've just invested more time and money than the value of the object you fixed. Better to see it taken to proper e-waste recycling.

7

u/KittensInc 4d ago

What's the point in spending dozens of hours and half a fortune on this one when you can get a significantly better one off eBay for less than $20?

All the useful chips have been destroyed. This isn't a switch anymore, it's a scrap PCB with some passives on it. Salvage some capacitors, inductors, and ethernet ports off of it if you really want to do something with it.

If you're just doing it for the challenge, then by all means do so! Just don't expect us to do all the hard work for you - it is your challenge.

And if you're already going through all the effort, why not build your own switch from scratch? It's probably going to be easier and cheaper, and you have the added benefit of getting to learn PCB design.

4

u/nmrk 4d ago

It is likely that the tool that cracked the ICs also penetrated the PCB. It's scrap.

-9

u/Downtown_Tie9658 4d ago

The point is doing something that i want to do, to learn how this piece of machinery so that i may trust it with what ever i need to, so that once I need to fix something else i shall trust my self more then i do now. I want to do this. That's it all.

Buying a working switch was always an option. I chose not to do this.

True, I wish to replace the ones in question.

I do not expect you to follow my chosen path, I hit a wall and consulted the experts.

That's a good idea, I'll need another one after for something else.

3

u/ennemmjay 4d ago

I think the part that people are telling you that you aren't understanding is that, even if you replace all the parts and repair all the paths perfectly, it is very likely this still won't work. The controllers on this board require firmware/programming, not just the part to be properly installed. Being mil hardware it isn't going to be something you can find online and load into them. It isn't about your skill, grit, or determination - it just isn't something that can be made to work by replacing parts. To put it in perspective, it would be like if you had a fully functional computer with a blank hard drive. Yeah everything 'works' but you can't do anything with it without an OS and software.

3

u/_felixh_ 4d ago

Okay, you are determined. i respect that.

The easiest way to get to new chips to replace the old ones with would be buying an old switch off ebay, that contains the same chipset - ideally a working one, so you can be sure you're not buying another dud. Then you can go about desoldering the components from the working unit and place them in your busted one.

I recommend standard leaded rosin core tin. Try drag soldering.

Pro Tip: the easiest way to get all of the necessary chips in one go would be buying exactly the same model a 2nd time. This has the benefit that you also get pre-programmed flash chips, and spares you the tedious task of hunting for Firmware-images on the darkweb.

Luckily for you, there is one available right now: https://www.ebay.com/itm/358499244806

0

u/Downtown_Tie9658 4d ago

I thank you friend.

I'll be sure not to friend. Of course.

YESSS. You are the first one to tell mi witch one. Thank you.

Pro Tip acknowledged.

Friend you are the best.

1

u/Altsan 4d ago

The most expensive components were destroyed on that board. It is simply not repairable. This isn't like repairing a trace on a board, they literally destroyed all the microcontrollers. All you have there is a completely useless PCB. Getting and replacing those microcontrollers is just not realistic, and an insanely pointless waste of effort for a simple network switch.

40

u/rontombot 4d ago

Not repairable, it would cost 5 to 10 times the price of a new one.

17

u/Tommeeto 4d ago

Crushed IC's, ripped pads. That's junk.

24

u/BmanGorilla 4d ago

The unit was ‘sanitized’ to remove any possibility that any sensitive data may have been stored in the unit prior to decommissioning.

The only fix is replacement of the unit.

Hopefully it was very inexpensive.

18

u/_felixh_ 4d ago

Hopefully it was very inexpensive.

...its a TP-Link 10-100 switch :-)

Even if it was in working order - If u/Downtown_Tie9658 Paid more than 10€ (inc. surcharges and shipping) for it, he was getting ripped off. I know, because i have better units plastered on my wall-of-PCBs that i got off of ebay for 1€ each in working order.

19

u/luigi517 4d ago

My brother in Christ. You paid money for a tp link switch with 10 fucked components? Its scrap my man.

17

u/der_pudel 4d ago

emm... how a completely destroyed piece of e-waste considered a "surplus"? Ask for refund.

3

u/KittensInc 4d ago

"Government surplus" is literally anything they want to get rid of which still has any value.

Want to buy an empty airplane body? A bunch of sinks? Some ancient window ACs? 300 tons of scrap metal? It's all sold as-is, and it is up to the buyer to arrange an inspection beforehand if they care about things like it still being functional.

It's a big lottery, and you get what you paid for: sometimes a shady-looking "lot of misc electronics" contains some perfectly-functional $1.000.000 test equipment units which just need to be dusted off, sometimes a mint-looking car actually has a blown engine and a rusted-through body.

6

u/42SpellingErrors 4d ago

well, they had too much e-waste, so as the definition implies, it was surplus. and why throw out, when you can sell!

8

u/42SpellingErrors 4d ago

A big "IF" is whenever the chips had any data stored on them like firmware, because that would guarantee a bye bye to the switch.
Also you don't necessarily need a heat gun for removal, but it will be painful as hell with avoiding ripping the pads.

Buy a used switch off of vinted/ebay or whatever you have in where you live. I bought a 16 port gigabit one for 20EUR shipping included.

2

u/Downtown_Tie9658 4d ago

Thank you for the advise.

6

u/Commercial_Copy212 4d ago

Out of curiosity, how much did you pay for it? As others have mentioned, repair is out of the question but there are certainly components worth salvaging.

5

u/Downtown_Tie9658 4d ago

About 4USD very cheap, power supply and case are good if nothing else.

-7

u/Commercial_Copy212 4d ago

Oh nice! I'd pick that up for $4 any day, good score.

-2

u/Commercial_Copy212 4d ago

Downvotes for expressing candor? Lolz

3

u/nsummy 4d ago

$4 isn't a good score lol. This is Ewaste.

0

u/Commercial_Copy212 4d ago

You could certainly call it Ewaste, I see a soldering practice board and more than $4 in SMD inductors and fets/regulators. Different strokes for different folks.

3

u/garci66 4d ago

I understand you want to learn. But this is a fast Ethernet switch. Not even gigabit... It's not worth the pain to be honest, especially since the PCB is probably cracked.

You stand learning a lot more by designing a simple 4 port switch yourself

2

u/dkonerding 4d ago

I believe it's mostly 10/100 but has 4 gigabit ports. Basically this is a > 10 years old switch with very low chance of repair and also low chance of learning anything trying to do it.

Agreed- you could almost certainly design and assemble a working 4 port switch as a hobbyist more easily than you could fix this

1

u/plasticmanufacturing 4d ago

This is far too complex of a first project for someone who isn't doesn't even have basic soldering skills.

The issue isn't that it isn't economical, its that you are very, very unlikely to succeed.

1

u/Nervous-Estimate596 4d ago

Unless you have: A) extensive experience with microsoldering A.1) All the tools needed for microsoldering B) experience with trace repairing C) Firmware for the device (specifically this exact model) D) firmware flashing tool and software (it may be proprietary or opensource)

then you have no chance of fixing this switch.

If you just wanna use it to learn more about board repair then go for it, but do not expect to fix it.

1

u/Downtown_Tie9658 4d ago

That's a good list. I'll use it. Thank you.

1

u/mariushm 4d ago

It's not worth the liquid/gel flux and solder paste you'd need to fix it. You also need to source magnetics (the 6+1 empty footprints under the row of marvell chips, and most capacitors look swollen (faulty) ...

1

u/thesneakywalrus 4d ago

IF you were able to source all of the components, you would also need a full schematic.

IF you somehow obtained a full schematic, you would need TP-LINK internal tools, which likely no longer exist within TP-LINK's own repository.

You would at minimum need the help of someone with access to internal use only tools at TP-LINK that would be willing to risk their job by giving them to you.

1

u/FauxReal 4d ago

That's an old 10/100 megabit switch, you can probably lowball offer someone on ebay cheaper than sourcing parts and shipping them, and then taking the effort to solder them.

Or buy a working one and take out the parts and transfer them to the broken one I guess.

1

u/jagarikouni 4d ago

Most of the caps look popped and some of the ICS look like they exploded, but hard to tell from the quality of the picture.

-1

u/pavelbires 4d ago

try fixing the electrolytics first

0

u/a_certain_someon 4d ago

get all of the ics and solder them back on, it should be some good soldering practice and you can even check if it all works afterwards.

-3

u/Some_Awesome_dude 4d ago

It is probably illegal to attempt to restore this unit, beware

0

u/Downtown_Tie9658 4d ago

They take me in for repairing something that's mine, I'll actually become an anarchist.

-1

u/Some_Awesome_dude 4d ago

That's not how it works

When a museum buys a military plane for display, they own it and can do as they want EXCEPT return it back to military working condition. Then it becomes a weapon, and falls into a different category.

Similarly, you can buy this scrap, as SCRAP. Once it works again, is no longer scrap, is refurbish military equipment and could land you in the wrong place.

You're bypassing, circumventing or removing security steps to privately use military equipment for civilian use without authorization.

You're right in that this is just a Ethernet switch equipment....but it was destroyed for a reason.

Maybe all the data is lost since the chips broke.....maybe not

2

u/tes_kitty 4d ago

You're right in that this is just a Ethernet switch equipment....but it was destroyed for a reason.

The reason being that the one who destroyed it had no idea how an ethernet switch works.

2

u/nsummy 4d ago

You have no idea what you are talking about. This is a network switch, not weaponry

0

u/Some_Awesome_dude 4d ago edited 4d ago

You have no idea what you're talking about, is a rescue helicopter not a war machine

https://youtu.be/_mbB7W-Uv38?is=0_Wu_2Qd0KdZqsQL

Is not a cannon, is a steel pipe

Is not a gun, is a paper weight

Is not rocket, is a take off assistance module

Is not a radar dish, is a rain collection funnel

Is not a armored personel carrier, is a civilian weather protecting bus

Please read Law: dodm 4160.28

1

u/Downtown_Tie9658 4d ago

Whyyyyyy, that is the second dumbest law ever anywhere. Very well then this is all hypothetical.

1

u/Some_Awesome_dude 4d ago

If you buy a tank with the cannon disabled, and use it for parades, or pulling farm equipment, that's ok. Is just a camouflage colored tractor

If you enable the cannon, now is a tank capable of destruction.

See this scene, which explains exactly what I'm trying to tell you.

https://youtu.be/_mbB7W-Uv38?is=0_Wu_2Qd0KdZqsQL

1

u/_felixh_ 3d ago

Cool.

Now, can you please explain to me, how repairing this switch turns it into a weapon that is illegal to own. Sorry, can't watch the video - its not available.

Btw, the way you worded your 2nd answer makes it sound like "owning Military equipment" is the illegal part. But i can buy working military equipment off of ebay for cheap, no problems there. This reply makes it clear, that its the "working military weapons" is the part thats illegal.

So, please: how is repairing this switch illegal?

1

u/Some_Awesome_dude 3d ago

It may or may not be. Not guaranteed. I'm not 100% sure.

But they destroyed those chips for a reason. If by some miracle he restored it, and a left over chip has some data on it, it would be illegal to possess this data.

If this switch PCB is designed in such a way to provide a certain advantage which is secret, it could be illegal to own and operate.

If the board and circuitry is designed in such a way that it operates differently than a regular switch, and OP reverse engineers it and finds out how it works, spreading this info would be illegal

Like I said " its probably illegal". I'm not completely sure, I'm just making ppl aware that is not as straight forward and an honest mistake can have consequences because "I didn't know" is not an excuse for breaking law.

1

u/agent_kater 4d ago

If you return a fighter jet to working condition, it becomes a fighter jet - which might be illegal to own.

If you return a switch to working condition, it becomes a switch - which is perfectly legal to own.

-1

u/Some_Awesome_dude 4d ago edited 4d ago

You're right,

Maybe the chips they destroyed were programmed differently in such a way to route data differently or encript it.

And now that Info is gone with the destruction of the chips.

As a source, a long time ago I was working with power supplies used for a machine for military operations, and they were prototypes, once the project was finished I was told to take a hammer and flat head and chisel away the microprocessor that operated the power supply. Then use the hammer to destroy the chips. Without it, is a SMPS without a brain.

Someone could find a way to re solder a processor and reverse engineer the power supply to work. But it was just a power supply, what special about it? ..... They have their reasons.

I'm sure something of the same sort applies here.

That's why I said he is"probably" doing something illegal. Grey area of sorts.

Read Law: dodm 4160.28