Just take a look at the mantra in my sig.
Jokes aside, the local dude who recapped my Duo used SMD ceramic caps wherever possible, if I recall it correctly. I think he even did the same preemptively when he modded my PAL SNES for NTSC games and 50/60 Hz.
My Duo crapped some years after that, must be something with the power regulators. Since I had other stuff to do, I havent't repaired it when I moved in 2014.
Oh and since the SNES was modded, I couldn't get any color for 50 Hz via Composite and S-Video anymore (only luma left), but RGB lines were still working. 60 Hz however is still sending color signals via all cables. But a lot of PAL games are optimised some way or another for 50 Hz and will freak out on 60 Hz.
I tried on a variety of Euro TVs (CRT and LCD) that accept pretty much any signals you threw on them, be it formatted in NTSC-60, PAL-50, PAL-60, whatever, via all of their input jacks.
I should get up and either try the repairs by myself or let my console repair guy have another look.
Please keep in mind I'm not claiming that these symptoms would be in any relation to the recaps, I'm just doing some brainstorming.
If you guys know anything about why there shouldn't be ceramics, please let me know.
TL;DR: Get your Duo recapped ASAP before it releases the shmoo. Sometimes you'll not see it easily since it builds up underneath the old caps, eating slowly through the PCB. This was the case for me.