MVS Sync and newer HDTV's

[GTRetro87]

Hello all!

I've searched literally everywhere but could not find any solid results.

My concern is the MVS's (MV1C specifically) and it's oscillator crystal which it's frequency is 24 MHz, like the older AES; and have a refresh rate of 59.18 Mhz.

I do know that the later model AES (3-4 to 3-6) came with a 24.16 MHz oscillator crystal, and output a refresh rate of 61.XX Mhz (I have to find the specific value). However, I'm not sure how they display on newer HDTV's


Now what I want to know is.. has anybody tried and found results to swapping these crystals??


I have searched everywhere for a similar crystal, and the only way to get one is to buy in bulk (about 590 as a minimum order at a $1.80 something rate....)..

Some other crystals which are more available (say from ebay) run around 24.5 Mhz which could still be tested but will obviously make things way above 60 Mhz..




Reason I'm concerned, I've noticed newer HDTV's have a hard time trying to lock onto a solid sync (if you've seen my posts, I'm referring to a Samsung F8500 51" plasma).. and regardless after playing with different settings on the TV..

Without any cap on sync, an MV1C (supergun) will display on this particular TV but will randomly flicker every so often.. My CMVS actually displays with a 0.01 uF cap on sync, but the screen rolls..


My CMVS on my TV works no problem regardless of the input I use (I've used composite, s-video and component on a 2008 Panasonic Viera 42" plasma).. and that's with a JROK encoder and Sync cleaner



Please chime in!


Ps... How do any of you feel about an XRGB mini, should there be no remedy for this problem on newer HDTV's..

 

[kahel]

I use a XRGB-Mini with a Supergun that output the RGB directly to my XRGB-Mini without any encoder or sync-cleaner. It works great for all the boards that i tried except the Taito F3. I get a jumpy screen with the F3 because of it weird refresh rate. But all the rest i tried , MVS (MV1-B), CPS2 i have no problem and they work perfectly with my XRGB-mini. You do have to find the good sync_level for each type of PCB ex I use 20 for MVS and 3 for CPS2.

I love my XRGB-Mini , it one of my best purchase .

 

[GTRetro87]

Hey kahel,

I am definitely considering one, should I ever get a new HDTV. I know CRT is the best for compatibility.. but I'm guessing that the XRGB mini will have to be the way to go. And yes being able to adjust the refresh rate definitely helps A LOT.

 

[Stephen.oneill]

I love xrgb-mini, I use it for my retro consoles as my LG HDTV just shows up the picture in a mess, I use the S-video cable on it for n64 and it looks great. But it has been a uphill struggle for my neo geo consoles.

For my AES on RGB I had to get scart adaptor from retro gaming cables. I bought one with no sync stripper and the picture was just constantly flickering. No amount of config can resolve it. Then I bought a scart adaptor with sync stripper which worked out great but the screen still gave a light flicker once every 20 or 30 secs. But is very playable

For my cmvs the picture looks great but I have been getting some interference issues, not sure whether that is due to the cable or framemeister (running latest firmware).

http://youtu.be/8TbOoyfGsLs 0:19 on wards is very obvious
http://youtu.be/tBAzWJbQNkY 0:16 if you look left of the M on "Metal"
http://youtu.be/0pGZGPtDTOs 0:11 on wards u can see the noise appearing all over the title screen
http://youtu.be/onNx8o1Ay1U 0:10 onwards is very obvious if you compare with this video... https://www.youtube.com/watch?v=1LYHhRNMVzI

Anyway just some sharing on the issues I have been having, but in general I would say the x rgb mini is the only hope for new HDTVs.

 

[GTRetro87]

You know, I've never noticed it until now but my S-video and composite were kind of funky up close. I noticed some interference with both, but interestingly enough, component was funky with the cross hatch!!! It would jitter, except for when a game was playing.

So I've tinkered since then.. I added a switch to toggle between a 0.01uF cap and plain sync, and this was placed on the sync input from the MV1C to the cleaner. The difference is the shift in the image on screen.

Component - image was centered with cap, off center without
S-video and composite - unstable and jittery with lots of interference


I had placed a 1K pot on the sync output from the cleaner to the encoder and it did almost nothing except cut out the image when turned passed 3/4.



I then replaced the switch and cap with the 1K pot, and now I am seeing a variable difference. The 1K pot, as said before, acts like a voltage divider.. and this now allows me to adjust the centering of the screen! Too far an adjustment, the screen either scrambles and fades, or acts jittery regardless of the input.

Composite and S-video still have some interference, which leads me to believe that a cap could be placed on the Luma for S-video - and then maybe I can jump and combine those lines to composite to create a better image from S-video - if that makes sense.



Either way, XRGB will most definitely be the best way to go as I still have not found any results in swapping the crystals. I think it would make a difference, but then again maybe in the end it's all voltage. I'm guessing yours too could also use a 1k micro-potentiometer on your sync, before the stripper? Or possibly you may need a cleaner? (don't they both use the same IC?)


Also, which version is your AES? You may possibly have the earlier version with a 24 MHz oscillator.

 

[dragonpt]

GTRetro

I had similar issues hooking up my MVS's on newer TV's ( lcd)
It works fine on Old TV's ( CRT)...

Xian Xi point me on the right direction with this solution:

- Add an 1k pot on the sync line, and your good to go

- Also adding 75ohm resistors into the video lines, makes wonders. ( in my case on RGB lines)

Without this, the sync on newer TVs was just horrible .
Hope it works for you ( its cheap and quick mod)

Regards

 

[GTRetro87]

Hey dragonpt,

Yea I read about placing 75ohm resistors on the video lines. But did you place the resistors on the actual AV jacks, or did you place them on (or from) the JAMMA then route wires from the resistors to your encoder?

Mine so far works well with the 1K pot, but S-video and composite have some visible artifacts when looking close enough during the crosshatch.. playing a game is almost unnoticeable.

I'm going to order some resistors and test them out.. see what happens.. If it only makes a difference on a few TV's with the resistors on, then maybe I can add something like a 3 pole switch to toggle the resistors on and off depending on the TV

 

[GTRetro87]

Actually.. 470-500 Ohm pots I think sounds better on the RGB lines. I mean, I know they'll affect color, though I'm not sure they'll affect the quality of the picture itself as far as artifacts/interference/vertical sync issues..

The JROK encoder already has pots to adjust RGB levels but I'm not sure they'll be any different from pots on the RGB lines..

 

[dragonpt]

You just need to add the resistors on the lines.
Doesn't really matters where you put them.

In my case since I have an scart TV -> RGB i always put my resistors inside the scart ( soldered on the pins)

Regards

 

[GTRetro87]

Oh, that makes sense then! Well, as soon as I get myself an XRGB mini, then I'm sure I'll need to mod the SCART cable to output proper levels.


I wonder, the JROK sync cleaner takes C-sync, separates it into H and V-Sync.. then combines it again.. maybe there's a way to adjust V-sync with a pot from the cleaner since there are small points to pull that signal from...


There definitely has to be others here that have fooled around with sync and could chime in ...bump....

 

[dragonpt]

Oh, that makes sense then! Well, as soon as I get myself an XRGB mini, then I'm sure I'll need to mod the SCART cable to output proper levels.


I wonder, the JROK sync cleaner takes C-sync, separates it into H and V-Sync.. then combines it again.. maybe there's a way to adjust V-sync with a pot from the cleaner since there are small points to pull that signal from...


There definitely has to be others here that have fooled around with sync and could chime in ...bump....

why don't you try to build an sync cleaner first, before wasting all that money on an XRGB ?

the few pieces are dirty cheap...

regards

 

[GTRetro87]

Well, I already have a JROK encoder and a sync cleaner lol. I'm trying to figure out how to remedy the sync issue after the cleaner with newer TV's

Unless you mean it's best to build your own? perhaps maybe a sync stripper and adjust H and V-sync from there?