1st Crack at PCB Soldering

[Daves69]

Had a slightly used Logitech Harmony One remote laying around here for several years now. It's been dormant since the LCD cracked due to my sitting on it after I had it for only three months. Although the remote still worked only the top third was displaying right with the rest being black. Checking into having it fixed was well over a hundred bucks so I just bought a new one. I kept the broken one around (like car parts) in case I needed something off it.
I recently found a supplier on GoldBay that sells displays for the H1 remote and decided to drop the 37.50 "buy it now" on it and try to fix it. (Thanks for buying that 4611S Tom)
You really don't know how fat your fingers are until you mess with things such as these. Searching the net and watching the sellers videos I was able to disassemble it without destroying it. Covered up screws, snap lock cover, and stick on grip pad makes it a task.
Removal of the cracked LCD was relatively easy. Soldering on the new LCD I had some issues. I used the seller's recommended 600° iron temp. It took me three tries (along with random expletives) to get the contacts soldered to the board and actually work. Unfortunately seems a few pads lifted on me.
Anyone have a thought on that 600° iron temp???

I'm happy it works again though. Now I have a backup for the one I'm wearing out.:cheers:

 

[Phreakish]

#1 thing that helps solder items like that is flux. I've always used paste flux (plubers style). I would clean the tip of my iron with it, and then but the tiniest bit on the contacts. Pre-tin the contacts and the board, then place the item and use a needle or wire to hold down the contact. Heat shortly until it all flows together, then remove heat. It takes far less solder than one would imagine too, and doesn't leave the silver caterpillars behind.

The only downside with paste flux is that it has to be cleaned away pretty thoroughly afterward. I would use alcohol and qtips or cotton swabs.

A very slightly damp cloth or sponge (very small, too) comes in handy to remove solder when removing stuff from boards. Heat the solder, then wipe it away. If you have a big glob of solder, I would use spare stranded wire, dunk it in flux, then heat it over the pad I wanted to 'suck' the solder from. The wire would pick up the solder and leave the pad clean.

Lastly, remember that soldering is like welding. The solder follows the heat. Put the heat where you want the solder to be, and don't use the iron to melt the solder. Apply the solder to the component joint, but near the iron's contact point. Sometimes (if the tip isn't clean) you need to use the tip to get the melt going, then run the solder down the part.

 

[67Dart273]

practice

flux.

proper solder (I like old school, lower temp lead / tin rather than silver bearing)

not too big an iron, get it hot QUICK and solder QUICK. So you don't want too small, either. You don't want to have to sit there with the iron on the work for any period.

"see". My eyes are bad enough now, and boards are SMALL enough now, that I finally got on ebay and bought some junk stereo microscopes. Bausch and Lomb, etc. "Regular" magnifier lamps work for some things, but not enough for me, anymore.

Similar to this, and then either buy or build enough hardware to support it. You want something about .7---1X magnification in the head, and then eyepieces "as you want." This one has 16X eyepieces, which might be a "little much" for some work. 5x -- 10X eyepieces more typical

http://www.ebay.com/itm/Bausch-and-...958725?hash=item2eebd2d605:g:4HAAAOSwgQ9Vp~N7

 

[swies]

Electronics Technician III here for reference.
Lifting pads is a strong indication of too MUCH heat.
Maybe that your 600* was good however, it may have been left on the pad / contact too long.
I flux tip and contacts, slight bit o' tin on both, then stick them quick and get the iron off.

Good news about the lifted pads.
Usually easy fix.
Super glue them back down, then use 'Conformal Coating' to keep them down and sealed up nice and tidy.

This will do the trick.
http://www.ebay.com/itm/MG-Chemical...217256?hash=item43bd72a9e8:g:5T4AAOSwgQ9Vp9FS

 

[Daves69]

Thanks folks. So I'm under the impression the 600° temp is good. LOL, the practice part is what I didn't do! Maybe some jewelry magnifying spectacles would help also.
The new LCD came as a kit everything necessary which made it worth the gamble to me.
. Triangle pry tool (1)
Kester 63/37 solder coil (8”)
ChipQuik de-soldering alloy (1/2”)
ChipQuik No-Clean Paste Flux (2cc)
Soder-Wick copper de-soldering braid (2”)
Foam Strip (light 'blocker')
Q-Tip (2)
Round Tooth Pick (2)
I don't know how many times I watched his video on the laptop while doing this.
Here's the link if anyone's interested...........
https://www.youtube.com/c/Harmonyremoterepair

 

[RedFish]

Majority of these things are built with solder paste and bonded in a oven at 200 degrees max.
Several years ago I took the face of my Kenwood head unit apart and changed all the blue LEDs to red ones. These Kingbright LEDs are about the size of a grain of salt. I swore that the camera flash blew the thing off my fingertip. LOL
Proved to myself, son, brother, that I could do it though, using a keen solder tip in 600 degree pen. The flux I use is a water like product made for foils and sold at Hobby Lobby.
.012 dia. silver bearing solder from Radio Shack.
In the end I filed the experience with jail and ***** house. The things to do once and never again.

 

[67Dart273]

Some boards are just crap quality, as well. I never did much intense bench work. When I worked for Motorola, we had to modify a bunch of (used) radio boards for a special purpose. These were on FM receiver modules used in what is called a "voted" system. Anyhow, there were several changes that needed to be made and I was marching right through them, but there were a couple of boards, that I simply just lifted those pads right off!!!!. I was flat amazed. "Whut I do?" I'm thinkin. These were simply "crap" boards.