So I found an HDTV on the side of the road, brought it home, took it apart, and found the problem. A blown capacitor. So I replaced it with another one of roughly the same value (original was 16 V 470 uF new one was 24 V 470 uF) but it's still not working. As I'm new to this I would seriously love some feedback! I think I burnt the board too much, here are a couple pictures
Electronic – Trying to fix broken capacitor, help?
capacitorelectrolytic-capacitorrepairreworksoldering
Related Solutions
It is likely but not certain that the capacitor as a tantalum electrolytic of about 10 uF to 33 uF capacitance.
Most of the following assumes this was the case.
THIS MAY NOT BE TRUE.
It may have been a Dilithium energy source or a transzorb or something else interesting and/or strange, but probably not.
If faulty, then removing it, regardless of what it was, may improve things. Removing it if not dead is less wise. See below re testing to see if this is a tantalum cap that has suffered the infamous tantalum eat-spike-and-die meltdown.
IF it is/was it may be hard short circuited. The location suggests it was a filter capacitor. It is not uncommon to use tantalum capacitors for this purpose. A voltage spike can persuade tantalum capacitors to break down and let their internal metal and produce a hard short circuit across their terminals.
If this is/was a tantalum cap then just removing it my allow the circuit to function again for test purposes with no cap in place, although it would then be wise to add a new cap.
It MAY have been an eg 0.1 uF ceramic.
More likely tantalum as above 10 uF to 33 uF, 16V rated.
Use of a solid Aluminum cap if same rating MUCH preferred - they do not self immolate.
Using a leaded aluminum electrolytic of similar raing in this location would work OK enough if original was tantalum. Short leads. Observe polarity. bend cap parallel to board when soldered.
Try this test:
Power off
Measure across capacitor with a meter set to low volts range.
If no voltage, proceed.
If any voltage at all, short across capacitor with a wire for 10 seconds and then repeat above test.Set meter to low ohms range.
Measure resistance across capacitor with both polarities.
IF this was a tantalum cap and IF it has suffered the famous and common hard short circuit failure mode then the above test should show consistently low resistance both ways. If it does it is a good but not certain indication that is a tantalum cap that has failed. Repeat this test afer the cap has been removed (see below). If the resistance has now changed and is higher one way the other or open circuit both ways you can be mear sure that this is a failed tantalum cap. Measuring across the removed component should give the same low resistance both ways result.
Important questions:
- Does the laptop still work?
If not, what are the symptoms?
If it works, dos the PCI socket work?
How did the fault occur?
If it was dead, does it work when the above component is removed?
There is a vast amount on web re soldering SMD components. Starting in a motherboard whch MAY be salvable is not ideal. I suggest you try the following on another dead PCB first.
This is aimed at removing the current capacitor. It is a sub-sub-sub set of smd soldering practice. That is too large a subject to deal well with here. The following sounds complex but is simple and easy in practice. Much harder to describe than to do.
Tools / material:
Some liquid flux suited to smd soldering use IF AVAILABLE. Not essential here. But IS essential for general smd use.
Fine tweezers that you are comfortable with. I prefer super sharp needlenose tweezers - others like blunter versions.
Good light. magnifier of sort that suits that lets you view component comfortably. I use headset with flipout screens and swivel out small round magnifier for extra detailed viewing. Makes you look like a Vogon starship officer.
Works well.
Some use magnifying glass on stand etc.Soldering iron, finest sensible tip available, well tinned, temperature controlled.
Fine solder
Sounds horrendous but really just a usual fine soldering setup plus tweezers.
Then:
Tin each pad of bad component with iron and solder till new solder nicely evident.
Place tweezer tips alongside component and then heat one pad vigorously while applying lifting pressure with tweezers. You can try to swap iron to and fro from end to end but heat transfer is usually good enough and fast enough that whole component heats. Dont do it quite this way if you were going to re-use the component :-).
Do not apply heat that way for more than 2 or 3 seconds - that should be enough. Continual "cooking" of board at a point may cause damage elsewhere. Unlikely but possible.
The above should allow removal OK. If not try laying iron alongside component and heating both pads at once while providing mechanical pressure with iron tip and with tweezers. Once you have moved it at all it should be easy to do as above.
It is possible to locate a connector like this, but you will need to put a lot of time into it. First determine if there is damage to the mother board. It is likely that some of the land patterns were damaged, looks like the connector was ripped from the board. If you find the MB is repairable, then it will be worth the search for a connector.
First look for any identifying logos or part numbers that may give a clue, then Google those numbers. If you get lucky, your done. Most times you won't find any number although. It is difficult to search the thousands of connector types from an electronics distributor web site, therefore I would visit several of the big competitors sites and request catalogs. You will receive 4" catalogs by snail mail shortly thereafter.
Once you have catalogs you will need to measure all aspects of the connector (I use a caliper for this) and thumb through many pages until you find a similar likeness. I would try places like: Newark, DigiKey, and Mouser are very popular here in the US. Your profile does not say where you are from, I'm assuming U.S.. If you do find one, then you have the task of soldering it to the MB. It is probably surface mounted, and that takes some skill. If you never have done it, I suggest you do a lot of practice first. Good luck!
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Best Answer
I'm afraid it's not so easy.
The fact that you've found a blown capacitor doesn't mean it's the only faulty component, nor even that it's the root cause of a failure that may have destroyed several components. It could have happened that another component may have been the root cause, and then its failure may have propagated down to the capacitor and blown it up immediately afterwards (for example, by delivering a voltage above maximum rating to it).
Each kind of component has its own failure modes. Some devices fail in short-circuit mode and get burned, making their failures pretty obvious. But others may fail in rather silent ways that can't be spotted with a simple visual inspection.
So, if you're not a qualified TV repair technician then your only hope is trying to get a service manual of that TV model (google is your friend) and navigate through it until you detect all failed components and isolate the root cause. Then you will find what's the actual difficulty of the repair, and be aware it can range from something as easy as just having to rework some solder joints, to having to replace an expensive and hard-to-rework IC.
Good luck!
PS: Your replacement capacitor looks like it has seen better times. Did you test it before soldering it in place?