Back to the revision 2 Aiwa mainboard, silkscreened 02-01. This is the one with some pretty serious damage and a whole collection of previous trace repairs running across the underside. At this point it’s the only one of my two CSD-GM1 mainboards passing power through to the Game Unit section, so I’d rather like to keep it working!

Today’s job is replacing the electrolytic capacitors. That sounds simple enough until you start finding previous repairs, great blobs of hot glue and components that don’t quite match the other board. Even poor little resistor R51 had managed to get caught up in the glue. Out came the desoldering gun to rescue it.

I’ve been using Rubycon capacitors for much of this repair, including some surprisingly tiny ones that fit nicely around the heatsinks. The smaller replacements look rather good, actually. Not everything went to plan, though, because I discovered that one of the larger capacitors was 4700 uF rather than the 3300 uF fitted to the other revision. That’s another part for the shopping list!

With that difference discovered, I went back through the board checking capacitor values rather than assuming the two revisions were identical. Most of the replacements went in without too much trouble, although all those repaired traces made it rather awkward to work around certain sections. I’ve also noticed some cracking around the tops of a few larger film capacitors, which I’ll need to keep an eye on.

There was a moment when I thought I was missing the 7806 voltage regulator. I’d managed to find some 7906 regulators, but those are the negative-voltage versions and weren’t what I needed here. Eventually I found the proper part hiding on a shelf. Naturally!

The capacitor work was progressing nicely, but there were still a couple of outstanding components to deal with, including that larger capacitor, and I wanted to go back over the repaired traces before getting too carried away with testing. I also managed to knock loose another previously fitted component while investigating the underside. As if this board needed any more excitement!

Came across a few problems on this one, never fear there are always more parts on order. One day these units will shine with perfection. Well maybe not exactly perfection, but they’ll function alright!