Really new to this, think I messed up a board I'm working on

[pavinski]

Hey,

I'm working a TCON board for my TV, unfortunately, I am unable to source the part I need, however, with a bit of modification, a board from a smaller unit in the same line can work instead.

I have needed to remove some caps and eventually, swap out the EPPROM module between the two cards.

I've only ever really worked on wires and bigger bits, so this is my first time needing to remove parts off the board, I've removed an array of caps that are needed to be removed. but I think I've completely frigged it up already.

These are the pads from the removed caps:



It's work mentioning I don't need to replace these, so if I've not done any irripairable damage to the board, no problem other than need to really practice.

Also - an additional question. Could someone tell me where the EPPROM module on this board? I know they're usually six-pin chips but I can count a couple on this board and they look identical, the numbers on them are damn near impossible to read too.



Really appreciate the help

Warmest

[sam_sam_sam]

Re: Really new to this, think I messed up a board I'm working on

Can I ask you what type of soldering iron were you using

You really need to use a temperature controlled tweeter soldering iron for this type of work

Even using this type of iron you need to take your time and not get in a hurry doing this type of repair because some of these circuit board are real shit-e quality and if you put to much heat to the pads this will happen

Now the way I do this is to have my iron hot enough that I grab the device and I can take it right off the board and not be on there more than 10 seconds

I hope this helps you

[diif]

Re: Really new to this, think I messed up a board I'm working on

Seems the heat wasn't hot enough. They should just come off with a decent sized ball of molten solder on the end of your iron.
The EEPROM has 8 legs, I'd guess it's the smallest of the three 8 legged components.
I remove top lighting and light from the side to help read the writing on ICs.

[momaka]

Re: Really new to this, think I messed up a board I'm working on

These are the pads from the removed caps:

https://www.badcaps.net/forum/attach...1&d=1599383087

Yeah, those are done for, no offense.

- If the pads came off very easily with the component while you were removing it, then your iron is probably too hot / too powerful.

- If the pads came off because you used force to push the component while trying to desolder it, then your iron was either not hot enough or not transferring heat well to the board.

Whichever the case, you don't necessarily need a temperature-controlled iron/station. I do most small SMD components like that with a plug-in, 30W unregulated soldering iron. 25-35W is typically enough for small SMD components. I don't suggest going any higher with the wattage over 35W. 40 will probably run too hot and lift pads as you experienced - that is, if it's not a temperature-controlled iron. Now, if you do have a temperature-controlled iron, then the power is not that important and you can easily go with anything (40-75W will do fine.) It's the temperature there that matters. For temperature-controlled irons, 330-350C is normal for just about any job, including SMD. The most important thing, however, is the tip that you use on your soldering iron. For SMD work, pencil/conical tips are just a pain. Chisel or bevel tip is what you should be using - preferably at least 2-3 mm wide. Or if your pencil/conical tip is made of copper, you can grind it down into a chisel tip (and thank me later. ) This is actually what's allowing me to use my cheapo 30W Radio Shack soldering iron "gun" for light SMD work, as I have ground/worn its original copper conical tip into a chisel/spoon shape.

The second but very important thing is FLUX. Either get some Rosin or Rosin Mildly Activated (RMA) flux. Bonus points if it's labeled that it specifically works for SMD/BGA rework. Just stay away from Rosin Activated and Fully Activated ones, or anything touted as "Plumber's Flux", since these tend to be aggressive fluxes meant for soldering copper pipes in houses and will usually eat up the traces away on the PCB. Also try to avoid water-soluble fluxes, as some can be a pain to clean up. No-clean fluxes are OK.

Also - an additional question. Could someone tell me where the EPPROM module on this board?

Can't say for 100% sure, but it's likely either U4 or U9... or maybe (though unlikely) U7. If you read the part numbers off of those and look them up online, you should be able to find which one is the EEPROM. If you're struggling with that, post the part number here (as best as you can read them, as sometimes we know it's hard to read those SMD chips.)