Marc936

anyone know of a site that shows you how to fix the cpu solder joints for the horn/radio/lights/etc and for the window wiper relay? i checked the entire archives and the sites that have them no longer work

RotaryEvolution

iTrader: (30)

you don't even need a walkthrough for this, basically the problem that exists is the connectors break the solder inside the units because the harnesses pull on the connectors and jar them constantly. the units are only held together by press fit so a small flat tipped pocket screwdriver will easily pop them apart.

visually inspect the solder joints and you will usually see one or in my case half a dozen broken joints that need to be resoldered. at this point you should heat up your soldering iron and you can either just melt the original solder and allow it to cool solid again or as i did you can add a little bit of silver bearing solder to aid them in fighting fatigue. then you simply reassemble the pieces.

Syonyk

Personally, I'd suggest resoldering everything you see. Mazda's solder joints... suck. Really, really suck.

Heat 'em up, and add solder. Most of them are dry joints (not enough solder), and a good number of them are cold joints (cooled off to quickly, end up very weak).

-=Russ=-

MarkPerez

it's a good idea to use a small wattage soldering pen/iron . something around 25-30 watts should be good, make sure the tip is 'tinned' and clean. it would also be good to have a spike tip vs a flat tip. no paste flux but rather liqued flux and a very fine small art paint brush to apply any flux. no acid core solder BTW.

Icemark

No, wrong answer on both of your sentences clueless one.

#1. Mazda didn't make any of the electrical components for the FC. They were mostly made by Nippondenso and Imasen. The electrical is no different than any other import car of the late eighties/ early nineties. And cold solder joints are typically of any 15 year old car, regardless of if it is a Mazda or a Lexus or a Porsche (in fact some of my best customers are Lexus dealers or Lexus or Porsche cars owners with the same problem of cold solder joints).

#2 you do not resolder cold solder joints by simply heating the joint and flowing new solder. See the joint is broken internally with corrosion between the joint surfaces. So to remove the corrosion (and if you don't they same problem will occur 6 months or a year from now), you must remove the old solder. Then you can flow new solder in.

Dry solder joints are almost unseen in import cars.. perhaps you are thinking of a Chevy, because of the hundreds (if not thousands) of CPUs, Wiper Switches and Logicons I have professionally rebuilt, I could count on one hand the ones with dry solder joints.

Icemark

Again wrong

You must remove the old solder or the same problem will occur again and again. See my above post.

Icemark

The wiper switches almost never fail from poor solder joints. They fail by the internal relay failing or from a SMD transistor failing. For rebuilding the wiper switch youself:
http://www.mazdamark.com/DIY_wiper_repair.htm or I can sell you an already rebuilt switch from my webstore Mazdamark.com.

The CPUs are pretty simple. Simply remove all the solder from where the pin meets the board and then flow new solder in. I also have rebuilt CPUs available on my website.