Duo Resurrection - What would you do? May 15, 2023 14:34:28 GMT
Post by stirlingsteve on May 15, 2023 14:34:28 GMT
Hi all, new to the forums and am looking for a little "what would you do" advice. First, a little background.
I've recently acquired a lovely Japanese PC Engine Duo which I know has never been opened and was therefore likely in need of a recap. It fired up to the boot screen fine but when I tried it with a HuCard, there was no sound (which I was expecting) and when I tried an audio CD, it span up fine but didn't get any further than that, which I wasn't expecting. Unfortunately, I don't have any CD games yet so I don't know how it would fare with one of those, but I figure if it doesn't fire up to the Audio CD menu then it's not going to be any better with a game!
I opened it up and could immediately see significant cap leakage but thankfully, very little (in fact no) board rot so clearly it's come to me just in the nick of time. The CD ROM unit looked a little grubby but otherwise OK. With no CD in I could see it moves the head to the centre as expected, then bobs a few times when trying to find a CD too, so outwardly all looks fine. As I said before, it spins CDs up as well, but seems to have trouble focusing or something, although I am no expert. I can see a very tiny red glow if I look at the lens from an angle with no CD in place which I think shows the laser is working, but I can't vouch for whether it's as strong as it should be because I don't know what they should look like when working.
I decided it was best to leave the CD ROM unit alone until the caps had been replaced, in case they were causing CD issues as well. I have since completed the recap (using quality like-for-like SMD and through-hole equivalents throughout), including the supercapacitor for memory backup and I'm happy to say the audio is back and the visuals are perfect. Sadly though, there is no discernible improvement with the CD ROM at all.
So now I think either the original laser has given up the ghost, or it's in need of a retune via the dreaded pots. I have read up on how these units can be adjusted but at the moment, the pots are all unmolested and factory-set so I don't really want to touch them unless it's absolutely the last resort.
So this finally leads me to the questions I have for you lovely people: What would you do at this point? Would you assume the laser is on its last legs and source a replacement now, in the hope that it'll work straight out of the box with the factory pot settings or is it worth risking those settings now and fiddling with the old laser to see if it'll work? I'm reasonably competent with a soldering iron and I do technically own an old Oscilloscope but I don't really know how to use it so I'm terribly frightened of messing with those pots unless there is literally no other option.
1) Do CD lasers commonly die over time? Is there any chance this one can be resurrected?
2) Is there any hope of a new laser working with the pots as-is or would I need to tweak them regardless? If so, is it worth breaking out the scope first?
3) Where would I be best finding one of these HOP-M3 lasers? Ali-express seem to have some but that's about it.
4) Does anyone fancy holding my hand? I'm scared...
Cheers in advance for all your support and advice!