Sega Megalo 2 50"

[Mr-Megalo]

1st up I'd like to say hello to y'all, I been tinkering with arcade cabs for about 18 months and didn't know of this place

[Mr-Megalo]

well after a week and a motherboard failure on my main PC I'v got no further on this and by the looks of it no one has any ideas on this one, am I the first person to do this ?  

ok thinking out loud here, what wire would you chaps reccomend (18, 20 or thicker ?)

The grounds on the fingerboard are all linked (I believe the phrase is there all common) does that make any difference ?

also finding the 5v on the megalo has puzzled me slightly, on the bottom shelf there are 3 knobs that can be adjusted , V ADJ 4vADJ and the last is 2vADJ (i think)

oh and anyone interested in printing me any sideart ? ? ? PM me if your in the UK and fancy earning a few bob

[Cave]

I built one of these lm1881 circuits too when i wired up my DC&PS2 to my 15khz jamma cab, I had all sorts of trouble getting power to it until i realized i could just use one of the pins from the scart connector, can't remember which one, but one does supply +2 or 3 volts, this worked perfectly this made it a self contained circuit inside my 4 way scart box.

Isn't your laptop video output going thru a scan convertor twice, once thru the averkey and again thru the cab convertor, maybe you could try and get 24khz straight from the laptop this could eliminate the scanconvertor completly, some software can do this(displaydoctor or something).Also only the consoles need the lm1881 circuit circuit due to the composite sync they output.

Don't give up

Cave

[Mr-Megalo]

Hi cave,

yes your right the laptop is going through 2 scan convertors , but that is because I prefer to use hardware (the averkey) to get the 15khz signal rather than using software like powerstrip to try and output 15 or 24khz when windows starts. It crossed my mind that it may have been signal degridation (hope I spelled that right) but the whole thing is identical with my DC and PS2 aswell as with the PC so I ruled it out pretty early on, I thought it may be the quality of the wire I am using but again, on my other cab all is fine

thanks for the info about the scart pin outputting enough to power the sync circuit, I did read somewhere (probably gamesx, I will have to check) that the 5v could be obtained from the scart lead but you just gave me the nod so to speak so big thanx for that, needless to say the good ol multi meter will be coming out to find which pin and then I can scrap the 5v from the fingerboard.

on a side note, when I tried my laptop without the sync circuit, neither arcade machine would sync   when I hooked the circuit up, they worked fine, I thought that the video sync was just H+V together but the scart lead with my averkey didnt like it one bit without the lm1881
My Sega saturn works without the sync circuit as that outputs composite sync.

oh another thing, when I was proof reading what I posted earlier (unfortunately after I hit post)  where I said "and by the looks of it no one has any ideas on this one, am I the first person to do this " I hope I didnt come off a bit uppety, it was NOT my intention, what i meant was no one have any idea about the flickering as there had been no replys, not that the whole lm1881 hasnt been done before, hopefully that sounds better  

Thanks for the tips , I'll let you know if I get any better results , im hoping to get some photos of it when its all up and running and a bit of webspace to host if anyone wants to see it when its done, and I am always open to suggestions on further modification if any of you guys have any ideas , here is a link to the cab in question http://www.arcadeflyers.com/index.php?page=flyerdb&subpage=flyer&id=3019&image=4
possible upgrade the Q Sound system as it is damn fiddly to adjust the bass on the sub woofer  as the amp is behind the power supply inside the Megalo and not in the seat itself.

[AndyWarne]

Using one scan converter is bad enough but two!! One of them (or both) is probably outputting an interlaced signal, hence the flicker. If you get rid of them and get the PC to send the native scan rate for the projector (is it 15 or 31Khz) you should have a great picture.

[Dave_K.]

Mark, 3rd Strike for DC outputs an interlaced signal, thats why its flickering...nothing to do with your setup.

[Mr-Megalo]

right, I've been playing around with this on and off for the past few weeks or so when I could grab a bit of time to spare, and I have more or less got it sorted, after spending hours adjusting  (and praying I dont fry myself and the cabinet) it does seem to be down to the 5v thats outputting from the cab, either that or theres a dodgy earth somewhere (damn metal cabinets!!) so anywayz, im not exactly happy with it so I have a few queries concerning the ArcadeVGA and the whole lm1881 sync circuit, my new plans are as follows:

1. get an Arcade VGA and a J-pac from Andy and put a PC inside the cabinet connected to jamma slot 1 (My cab has 2 jamma connectors for more than one game)

2. Do as Cave has done and make the scart box up from one of those multi scart box's and grab the 5v from somewhere other than the cabinet.

Soooo ,what I now need to know is, is the ArcadeVGA any good with emulators such as Kawaks, Nebula, ePSXe , and does anyone have any idea which pin on the RGB scart lead outputs 5V coz I cant find it for love nor money. I can confirm that the problem I have is nothing to do with the signals being interlaced etc, anyways hope someone has tried ArcadeVGA with other emu's and can report back ,and hopefully I can get this thing finished within the next week or so, so your replys will be mostly appreciated

[Cave]

I'm sure its pin 16 thats +5 and take the GND from the scart aswell, also epsxe and others look great, you could probably run epsxe on your cab with AVGA and a real psx on a scart tv and be pushed to tell the difference.

Cave

[Mr-Megalo]

Ah ! take the ground from the scart (im assuming you mean the ground for the lm1881 circuit), now that is one thing I havent done, I always gave it a ground from the fingerboard, Cave your turning out to be a real life saver, I'll give it a shot 1st thing in the morning, and if I'm right is pin 16 the same pin that switches between 16:9 mode on some tv's when you first turn on your console ( on my Sony Trinitron - auto widescreen when it swaps to AV channel).

Thanks also for the heads up on ePSXe working ok too IMO ePSXe is in some ways better due to the plugins etc so Tekken 3 should look sweet on the big screen configured properly, Im hazzarding a guess that Kawaks, Nebula etc should work as they can be run at 640X480 and 800x600