jvs->jamma: gonbes8220 problems *solved*

[paulITA]

hello guys

need some EASY help.

i'm quite new in the arcade world, so sometimes i loose myself in a glass of water

i'm converting a sega naomi universal cabinet to jamma. nothing so special....
i've bought a gonbes 8220 video converter

and not should plug everything to jamma.

till now, all perfect.

the problem is: where does this cables from the 8220pcb need to be soldered on the jamma plug?
the are 6 cables: R G B S VS GND
red green blue and ground are ok

BUT

where does the fith and sixth cable go?!?!
one is SYNCH and the other one?!? where should i solder it?
i've added a picture that explains better what i need to know....

looking at a jamma pinout i can't figure out where it shoulds go...

thank you to everybody

[baddy]

S = Horizontal synch
VS = Vertical synch

Some monitor take both on the same cable, some on separate. Juste put both cable on the same pin of your jamma loom.

[paulITA]

yep, i knew that they were horizontal and vertical, just can't figure where they should go on the jamma plug!

thank you very much, will try to put them on the same place

[paulITA]

ok, i have tryed to put both cables.

nothing has changed

monitor still doesn't want to set image properly. it seems like it doesn't scan properly....

i will upload pictures...

everything would be good at this point.

i've tryed every way to plug those cables in the right way, even changing grey "S" ho "HS" (yellow is VS), but still nothing happends....

please help, i'm stuck

[baddy]

I would check your ground and synch signal.



Pin P for Synch and 14 for the ground.

If you still have an unstable picture, it might just be that your converter is not properly configured and is not outputting 31k signal to your naomi. What screen do you have in it?

[pulstar]

If you still have an unstable picture, it might just be that your converter is not properly configured and is not outputting 31k signal to your naomi. What screen do you have in it?

I was going to suggest this. Is the resolution set at 640x480 on the upscaler? Maybe post a picture.

[paulITA]

will shot a picture and show you what i've got.

at the moment, the setting is exactly as baddy shows, with ground a synch at theyre place.

will shot a picture of my jamma loom as well

thank you very much guys

[paulITA]

photos
https://imageshack.com/a/Uc1z/1"

thank u again guys

[baddy]

Im still thinking your converter board is not setup correctly, did you follow the following procedure? Also did you check the 5v on the converter?

http://www.jammaboards.com/faq/article/ ... up-13.html

[paulITA]

ps: i have the original 31k naomi's monitor, not sure 100% but should be toshiba

[Milspex]

get this:

http://arcadeforge.net/Scaler-and-Strik ... c453ec2fa1

[Asure]

That's what he has, it's a rebadged GBS for more money.. why would he get that.

@Paul, you need to connect only R/G/B/Sync
Also, you need to select the input channel on the GBS 8220. it has three inputs if i recall correctly. I have mine boxed up at the moment



I used a PC monitor first, the GBS8220 is defaulting to 800x600 VGA most of the time. Used the menu & the 4 buttons to set to 640x480 output. I don't think that the Naomi supports 800x600
Once it is setup for 640x480, exit the menus so that is saved, and power off. Then connect back to your Jaomi.

I only connected vsync to jamma SYNC pin. Not hsync. If that does not work, just use the other, as suggested.

[RMRM]

S = Horizontal synch
VS = Vertical synch

Some monitor take both on the same cable, some on separate. Juste put both cable on the same pin of your jamma loom.

This may also be the problem but not all chassis like both cables on the same pin. I had to put a switch to alternate between the cables because some games simply wouldn't sinc with both signals at the same time.

Just a thought...

[Milspex]

No I meant get the jamma adaptor..

[paulITA]

Solved!!!
Thank you guys!

It was too simple, the setting was wrong (800x600) than the Naomi doesn't support...
And without the help of a second PC monitor anything would have been solved.

Simply I wired only the S wire from the gombes on the synch position on the jamma plug
Set the board on 480x640 and turn on the Naomi... And everything worked as should

Thank you again for your help ASURE, I came from the pinball world so monitors issues are quite strange to me :-/