Wei ya M2929DC-62 sync problems

NeoBahamut · Post by **NeoBahamut** » Sun Jan 04, 2009 6:44 pm

Hi!

I have some sync problems on my Wei ya M2929DC monitor. It should accept 15-48khz, but so far only my CPS2 and STV systems seem to work. I tried with a Neo Geo as well, but I only get rubbish or nothing at all on the screen.

Some voltages:

Neo Geo: Blue/Green = 0,51V, Red = 0,46V, H-sync = 3,95V

= NO SYNC

CPS2: BLUE/GREEN = 0,3V, RED = 0,45V, H-synk = 2,4V

= SYNC!

Any thoughts on this?

/Jon

Post by **Dave_K.** » Sun Jan 04, 2009 8:40 pm

These newer/digital tri-sync chassis were built for 31khz with separated sync, and fall down trying to decouple and display combined sync in 15khz games with refresh lower than 60hz. I've had similar problems with Kortek and Neotec chassis not displaying Neo-Geo and getting scrambled unsynced Cave SH2 and GNET.

First make sure you are using the correct input to the chassis (5 pin header for combined sync). If that still fails, my next guess (which I haven't had time to try) would be to separate out the combined sync via LM1881 circuit and then feed that into the 31khz pin inputs (with separated Hor/Vert pins).

You may also want to ask on arcadeotaku.com forum, as they have many more egret 2 users who upgraded their chassis to wei ya.

NeoBahamut · Post by **NeoBahamut** » Wed Jan 07, 2009 9:17 pm

Thanks for the tip. I'll check with arcadeotaku

antron · Post by **antron** » Wed Jan 07, 2009 9:55 pm

Dave_K. wrote: If that still fails, my next guess (which I haven't had time to try) would be to separate out the combined sync via LM1881 circuit and then feed that into the 31khz pin inputs (with separated Hor/Vert pins).

i have wondered about this. the lm1881 outputs V and C Syncs, but not H. Would you feed C to H?

Post by **Dave_K.** » Thu Jan 08, 2009 3:44 am

antron wrote:
Dave_K. wrote: If that still fails, my next guess (which I haven't had time to try) would be to separate out the combined sync via LM1881 circuit and then feed that into the 31khz pin inputs (with separated Hor/Vert pins).
i have wondered about this. the lm1881 outputs V and C Syncs, but not H. Would you feed C to H?

Good point. Its been too long since I looked at this circuit. I suppose its still worth trying to see if V sync will stabilize the picture if C sync alone cannot. And yes, almost all arcade monitors accept C sync on the H input.

zakk · Post by **zakk** » Thu Jan 08, 2009 3:59 am

I use one of these: http://www.extron.com/product/product.aspx?id=sc210