What can cause the Duo Super System ROM to not load?

[HuDuo]

I got a black Duo in, the previous owner(s) replaced some caps at the back of the board by the AV port and some solder pads were gone, there were patch wires. This Duo worked fine with HuCards and CDs, after putting in a new laser. Internal Super System ROM was fine.

I installed a console5 SMD capacitor kit, this would be my third Duo recap after two successful ones. I left the original patch wires alone and repaired any other bad solder pads I found under the other caps. I also installed the 2 capacitor jailbar fix for Duos just in case.

Now this Duo has an issue where the Super System ROM no longer works, HuCards do work though. I tried using a Super System Card 3.0 and the CD drive doesn't work at all, still with its new laser.

I'm away from this Duo for the rest of the work week, but I'm really hoping this sudden downturn in functionality is due to the jailbar fix or something else easy. Can anyone here explain how the Super System ROM in the Duo can stop working? What parts of the system does that ROM depend on to work? Can broken capacitor traces cause this issue?

[Keith Courage]

I hate these problems. It is usually caused by a bad connection/trace but this can also be the sign of a faulty chip on the motherboard.

I most cases, bad traces/connections underneath the Hu card slot are the problem but it some cases it can be bad traces to the largest GD chip on the bottom of the board(or faulty chip altogether).

However, I should also mention to double check your caps that you just changed. I've had a few times when using ceramic caps that one of them ends up being faulty right from the initial install. There are a few spots on the board in particular that can cause a white screen boot up for the CD bios when these caps are bad.

[HuDuo]

Which capacitors exactly can cause this issue? You were using ceramic caps? I'm using plain electrolytics from console5.

[Keith Courage]

Any of the 22UF caps in between the Big black Heat-sinks and the card slot. Double check that none of the positive and negative pads aren't accidentally arching to one another.

If those check out fine, then there is most likely a bad trace underneath the Hu card slot somewhere.

[HuDuo]

I had a look at those capacitors behind the hucard slot and it turns out there was a tiny solder bridge on one of the caps, I cleared that away and now the super system rom is working again! Thanks

Now to get the CD drive recalibrated after the cap kit.

[Keith Courage]

Excellent! Glad it was an easy fix.