Flow solder in CCU
 

Morning,

I replaced my aux water pump the other day. I'm planning on taking my CCU out this weekend - from what I understand from all the posts on the subject I need to repair this unit, it sure don't work right. When you flow solder do you just move the iron on top of the solder without putting any more solder on it? Also, will this be in a line, or just one point to solder? I'm winging it. Thanks for your help.

Hugh. Sr.

1984 190d 134,543 excellent condition

Heat each solder point with the soldering iron. Add a bit more solder. Don't glob it on, you'll end up shorting the adjacent points. The points your really want to hit are the terminals where the little side boards attach to the main board. There is a little flex here and that can lead to cracked solder joints over the years.

I like to use fresh rosin core solder, and touch just a bit of solder to each joint.
do not use acid core...
have fun!

Why not acid core?

As the name suggests, acid core has a corrosive flux core which is used for soldering copper pipes. The acid literally removes the surface layer of the pipe for better bonding of the solder. You definitely don't want that corrosive flux traveling to other parts of the circuitry. Talk about never-ending intermittent problems!

For electronic soldering, use resin-core solder which is less corrosive. Even then, use a cotton swab, saturated with alcohol, to clean up any traces of flux after soldering.;)

Yeah, use the proper solder.
The screwdriver is pointing to a cold solder, (a hairline crack surrounding the pin) you may be able to just touch it with a soldering iron letting the solder there reflow, or just add a bit.
Be careful to not connect a couple of pins with any added solder.

The pins where the pushbutton switches attach to the circuit board are the most likely to have cracked solder joints. Pay special attention to them. That is where the mechanical stress is focused.

Ken300D