exxos's Atari, Amiga & retro forum

So the Saturn has been a bit unstable of late, it needs a warm up period before it runs properly, so I've got a cap kit on the way.

I'll post more pics once the kit arrives and the Saturn is on the bench.

Well, the cap kit arrived from RetroSix today:


I'm frankly staggered by the number of them, it's gonna be a long job I think...

I recapped my Saturn a year or so ago, I luckily had pretty much all the correct values in my own stock. Has that kit got PSU caps in it too? Also are you not considering getting an ODE? I use a Fenrir, very affordable and works great.

Steve wrote: 28 Oct 2023 00:28 I recapped my Saturn a year or so ago, I luckily had pretty much all the correct values in my own stock. Has that kit got PSU caps in it too? Also are you not considering getting an ODE? I use a Fenrir, very affordable and works great.

Not sure why, but nearly every time I need to recap something I never have all of the caps I need, so I just went with the kit, though to be fair I don't keep a huge stock of caps. I think it does include PSU caps too.

I have a Pseudo Saturn Kai, so I don't need a Fenrir as such, but I am considering one in the future for sure, though not sure how it plays with the PSK which also gives me 4MB of storage.

Yesterday was re-cap the Saturn day, and what a lot of caps it was!!

The machine itself is really quite easy to dismantle, so getting the stage of 'a pile of Saturn' didn't take long:


First up for recap was the CD unit:


Removal is quite simple, the unit lifts out as soon as the top of the Saturn comes off, and there are just two cables to unplug and one earth strap that's screwed to a central point and joins the mainboard GND to the CD drive GND.

The biggest problem with the CD board is that the CD drive motor needs to be desoldered from the board to separate the laser assembly from the PCB. You could in theory replace the caps without separating the two, but it would risk damaging the laser assembly whilst handling to replace the caps. It's only the 2 connections, I just mention it so you know there are options, as it's only about 5 caps, but my preference was to be sure the laser assembly was protected.

Before starting the mainboard replacements I always like to mark the tops of the old caps with a Sharpie to make sure my progress is tracked:


It is a slower process as it means I do one at a time, but that's fine for me. One thing I did find with the Saturn board is that the combination of large ground planes and very hard solder made the caps quite difficult to desolder.

I ended up using a 2 pronged attack as my desolder gun, even at 480C couldn't melt the solder, so I used a heavy tip on my iron at 450C, which with some flux did allow the solder to melt, and then brought in the desolder gun to suck the solder away.

I don't advocate high temperatures, I usually work at 370C for my iron, and about 390C for the desolder gun, but as long you are sensible and don't over do things, it works very well. The Saturn board really does seem to be quite hard to work with (At least my VA9 variant) and does need some alternate soldering techniques.

The final result can be seen here:


You can see the 30 odd old capacitors just behind the board, and this brings me to the problem of the cap kit from Retrosix.

You can see that some caps have had to be laid on their sides in order to allow the top RF shield, which MUST be fitted because the CD drive mounts are on there. These caps that are laid down are normally low profile, but they are not low profile in the kit, whereas the rest are fine. I added a spot of hot glue to these caps to prevent any movement.

I really don't like this, it looks a bit 'bodgy' and while the kit contains enough caps for any variant of Saturn, for me, it's a poor option when you have to make compromises like this, so despite it being a reasonable price, containing decent quality capacitors and covering many variants, I don't think I can recommend it as a kit. To add to this, the kit doesn't contain the 5 caps needed for the PSU, so I will need source those separately.

Stability of the Saturn has definitely improved, so worth doing though. Also, despite the trouble soldering, props to Sega for clearly marking the capacitor polarity on the top of the mainboard, but also for marking capacitor locations clearly on the underside of the board, it certainly made the process much easier.

Now, where did I put my Space Harrier disc :)

A well deserved good break is waiting for you now...

HigashiJun wrote: 29 Oct 2023 11:14 A well deserved good break is waiting for you now...

It's also the last day of my annual leave, so definitely one for relaxing, and the Saturn is just so good at bringing back the arcade days I remember so well.

Though I have been playing Tiger-Heli on my Evercade a lot, it was a favourite back in the day, that day being in the mid to late 80's...

And now my mind is drifting to the Sidearms cabinet that replaced Tiger-Heli in my local, and that takes me over to the PC Engine. Damn so much to love about arcade cabinets in the mid to late 80's and early 90's.

30 caps is a bit of a marathon, especially with iffy solder.

I usually have my iron set to 280C for leaded as that makes the solder oxidise less quickly and my soldering iron tip doesn't tarnish quickly. The Hakko desoldering gun I use at 350C.

stephen_usher wrote: 29 Oct 2023 11:50 30 caps is a bit of a marathon, especially with iffy solder.

Yep, due to the many different values I really had to do it one or two at a time, I think the biggest group was 4 that were all the same, so it was slow going for sure. It did speed up a lot once I figured out the best technique.

stephen_usher wrote: 29 Oct 2023 11:50 I usually have my iron set to 280C for leaded as that makes the solder oxidise less quickly and my soldering iron tip doesn't tarnish quickly. The Hakko desoldering gun I use at 350C.

Yeah, oxidation of the tip was an issue, but I wasn't overly bothered for desoldering and used quite a bit of flux as I was going, but for soldering, it was fine at 370C, and with added flux it flowed well even into the heavy GND plane vias. With my particular solder station, which is an inexpensive Chineseum dual soldering iron and hot air station, setting at 370C seems to be the sweet spot for most soldering (60/30 leaded), and I also use it for desoldering with wick. Is it actually 370C, well that's debateable, I will test it one day (Perhaps this afternoon).

I'd like a Hakko desoldering gun, but can't justify it just yet, as my Duratool (Which is a lot better with the genuine filters) is not that old. I suspect that temps might be a bit optimistic on it too, so need to have a check.

So for now I have to go with what my devices say, though I'd always recommend people don't use my settings as a guide for their own, there may be significant differences, so use what works with your kit.

EDIT - I just used my IR camera and my iron is running more like 350C when set for 370C, same for the desolder gun when set for 390C. Will have to invest in some better gear in the future perhaps, but I can work with it for now.

Caps now ordered for the PSU.