Impossible to get sync!

[fcobenitez]

Hey guys, first time posting in this subforum, thanks for all your help



I've been trying to set up this monitor for a while now. At first, I tried hooking it up (after mounting it to that wooden case) to my 15khz capable PC, which is known to be working good. No sync at all, scrambled picture... Ok, I thought, maybe I need to do a fresh install of CRT_Emudriver and Groovymame to get this to work? Anyway, I left this at my bedroom.

Last week, I started messing around with it, this time with my Neogeo 1slot mobo, and same issue. Scrambled picture, at first it stayed like the video shows but then started moving, like when you are having H.Hold issues.

I've tested with two good jamma harnesses, and I made sure to be plugging the connector right (it uses a 5 pin connector, RGB-Gnd-Sync).
It's a 19" tube with a no name chassis, I think it's Eygo or one of those, because I have several of the same chassis (same component location, etc) but with different board colors and pot labels (for example, in the video I'm messing with V-Hold if I remember correctly, and it makes the picture start rolling as you can see. I also found a pot in the chassis facing the tube which controls the 'other' Hold, but still no luck, no sync at all.


Sorry, I don't know how to make the preview visible inside the post

So, messing with pots makes no difference, cables are good, and I've tried with both a Jamma source and a 15khz PC video signal.
Is there something in the chassis that can go bad and cause this to happen? Hopefully, a reflow / resoldering can help, but I can only take a look at this in the nights after work

Thank you all guys

[fcobenitez]

Alright, here are some pictures of my chassis. As I posted before, the only 'model' writen anywhere reads "RODO 850716", and now I noticed that the neckboard says "RODO 75026". (Brown PCB)
Also, there's one of the chassis that I have that looks really like the Rodo that I'm having issues with. This one is also faulty, but I can't remember what the problem was. It looks like the flyback has leaked? (Green PCB)
Album: http://imgur.com/a/icpbN
Thanks again

[ed12]

would u mind posting a picture of the unit's main board ? but more towards the r/g/b/g/sync input area ?
I think I know the problem but I just want to be sure

ed

[fcobenitez]

Thanks ed12,

I've uploaded a few pictures more pictures here:

http://imgur.com/a/hnMmW

Please, let me know if these are enough. Sorry for the bad quality, I cant find the DSLR charger.

[ed12]

from what I see
that monitor is a + going sync only
and u want - sync

ed

[fcobenitez]

Gotcha,
so I need to get a 74c04 chip, looks like a very simple and straightforward installation, 1 pin to -sync from game board, 1 pin to +sync to chassis, 5V and GND.
Will try to get a hold on one of these this week and will posts results. Thanks ed12! Just out of curiosity, how can you know that a chassis needs +sync just by looking at pictures?

[ed12]

look at the input "coupling"

ed