Main > Project Announcements

Pacman/Galaga 20th & 60-in-1 Multigame Bartop Build

<< < (3/3)

CraftyMech:
Had a minor setback this morning... given the age of the equipment I am working with I was half expecting something to stop working. The monitor powers up and still works great, but now the 12v and 5v rails are dead. A little refresher from earlier in the thread, the monitor I am using is from an old Compaq all in one PC. So there is an extra pcb attached to the monitor that provided power via the old AT spec to the now removed PC motherboard.

I repaired a power supply once about a decade ago, but honestly they make me nervous. I'm encouraged that the monitor still works, so that seems to imply that the high voltage portion of the supply is working correctly and I don't need to get close to that stage. On the other side of the board is an AT connector, and right next door are 2 voltage regulators for the 12v & 5v rails. Measuring with a multimeter the traces leading into those regulators have no power at all.

I am a bit bummed, but the project goes on! If I can't get the supply working again I'll just opt for an arcade power supply since they are slim and compact. Just a shame to have that third monitor pcb taking up space and not providing any functionality.

CraftyMech:
One thing I've noticed about just simple hardware scanlines is that on low-res games (Pacman, Galaga, etc..) they do the job, but removing half the pixels from a low-res display doesn't do any favors to text, and small bitmaps.

So I modified my scanline generator to handle variable intensisty scanlines via a trim pot for each R,G,B signal. The intesity of the scanline can now be adjusted from near black, all the way up to the point were the scanlines basically vanish. I personally found a setting of 1/3 intensity to work the best. At that intensity, the scanline rows are filled in enough that you don't get the impression half the display is missing like you do with a black (blanked out) scanline.

 I've been thinking about scanline orientation, and switching to the 1.8v version of the microcontroller I'm using so that I can use the vsync line as the power supply.

CraftyMech:
I should really google topics more before I just dive in... just found a long thread from a different forum about a scan line generator called the T-SLG. Basically does exactly what my design does, so reading up on it would have saved me several days of fiddling. I may stick with my micro controller setup, or switch it out for the two ICs the T-SLG uses. Either way I need to get back to the task at hand, finishing up the cabinet plans and start cranking out some sawdust!

CraftyMech:
Here is a photo of my scanline generator, which I am dubbing the "mini SLG". I think the footprint could still be about 1/3 smaller. I won't have a lot of room in my bartop design since I am using a CRT monitor, so every little bit of space saving helps. I'm going to go with this prototype and see how it works out, my only concern is cabling since VGA cables are heavy, shielded cables and not very flexible.

CraftyMech:
Accidentally posted this update to my bartop thread instead of my "side-projects" thread. In any event, the photo below is my latest build of my scan line generator that I'm going to use in the bartop. The design shrank down nicely!

Navigation

[0] Message Index

[*] Previous page