Makvision digital conversion?

[tebrown]

So, I finished building my arcade and didn't do enough research before I purchased my monitor. I ended up with a Makvision 27" Multisync monitor, which is a nice monitor and will do what I want except it's analog. Sadly, I didn't realize this until I had the monitor sitting in a box in my garage, and by then, it was too late. So I run it fixed in 640x480 and have mame do all the scaling.  Well, if I was going to run in a fixed resolution, I would have definitely bought a different monitor. So now I'm stuck with this one and will try and make the best of it.

My idea is to replace the analog adjustment board on the Makvision with an Arduino driving some digital potentiometers.  The Arduino would sniff the VGA out sync rate and adjust the digital potentiometers to the correct value based on the current refresh rate.  Unfortunately, I am not electrical engineer, and although I have the schematic for the monitor (http://na.suzohapp.com/service_center/pdf/support/Makvision/49-2715-00schem.pdf) I can't quite figure out if there are any digital pots that can drive the voltage required for vertical adjustment pots and tolerate the current requirements.  If someone who is more skilled in the electrical engineering discipline than me wants to help me out with this, I'd appreciate it. I can definitely do the software for this and I think it would be a great project. It would really make those analog Makvision monitors a LOT more useful.

[lilshawn]

my advice...sell it and get what you need.

although possible, all the farting around you would have to do is going to exceed the loss generated by selling the monitor and buying something else.

sorry 

[MonMotha]

I'd be inclined to agree.  Analog monitors are quite useful in conventional arcade applications, and they're often even preferred by operators as they're usually of somewhat simpler (or at least classic) design and may be easier to troubleshoot.

Also, digital pots have their limits.  I'm guessing that many of those pots can't just have a digital pot substituted on them.  The biggest things to watch out for will be power dissipation and maximum voltage, but digital pots are also not available in a particularly wide range of end-to-end resistances.

[StephenH]

You might contact Rick Nieman and see if he might be able to order you a digital replacement chassis for that tube perhaps.

[tebrown]

Thanks guys. As I continued to research this, I do believe that you are right and that as much fun as it would be to try this project, my level of expertise and the physical limits of digipots would probably spell disaster. I'll contact Rick, but I think for now, I'll stick with 640x480 on the monitor I have. It's not perfect, but at least I have a functional arcade. That's a lot more than I had last year at this time!

[Rickn]

If I had a solution I would be happy to support you even though Makvision is our competition, we believe in customer support.
Sorry to say it is unlikely you will find what you seem to be asking for.
In order for the monitor to auto adjust and remember settings it needs to have a microprocessor and memory. It will need to see the horizontal sync pulse to determine the resolution. As far as I know if you were able to find a board that claims to be an add on, it will actualy just detect the signals resolution then convert it's out put to VGA (640X480 @ 31Khz) and send it to the monitor.
In that case you might as well just set Mame and your Video card to VGA and leave it.

[tebrown]

Thanks Rick.  If I had known that Nieman and Makvision were competitors, I would have definitely made a different buying decision.  That being said, it looks like you don't have any 27" tri-sync digital monitors either?  If not, it seems to me that the best choices are dependent on if I want a CRT or LCD and size. If I want a CRT or anything 4:3 over 19" , I should get the 27/29" VGA/SVGA monitor.  If I can tolerate 16:9 and want > 19", the LCD would be a better choice.  I know this has been discussed ad nauseum here before so I apologize for bring it up yet again!

[Gray_Area]

Thanks Rick.  If I had known that Nieman and Makvision were competitors, I would have definitely made a different buying decision.  That being said, it looks like you don't have any 27" tri-sync digital monitors either?

No one does. Few have CRTs.

[thefooz]

If I had a solution I would be happy to support you even though Makvision is our competition, we believe in customer support.
Sorry to say it is unlikely you will find what you seem to be asking for.
In order for the monitor to auto adjust and remember settings it needs to have a microprocessor and memory. It will need to see the horizontal sync pulse to determine the resolution. As far as I know if you were able to find a board that claims to be an add on, it will actualy just detect the signals resolution then convert it's out put to VGA (640X480 @ 31Khz) and send it to the monitor.
In that case you might as well just set Mame and your Video card to VGA and leave it.

Rick, if I'm not mistaken, the 29" nanao ms-2931 I've got in my cabinet is a digital tri-sync (15,24,31khz). It also has a vga input, though I'm not sure if that was added on aftermarket. Anyway, it does an amazing job of switching between the various refresh rates. However, you've definitely piqued my interest with regard to your monitors. The quality looks solid.

[Rickn]

Hi I Can not be sure on the Nanao MS2931 as we did not build that for them.
The picture tube was only available in Japan!
The model # does indicate the following
MS ... multi sync
29 means 29" diagonally from the outside of the glass (not viewable but check the CRT, if it indicates someting like A68, or M68 the 68 is the viewable in centimeters, divide  by 2.54 and you will have the viewable in inches)
The 31 should be an indicator that the maximum frequency is VGA 640X480 at 31Khz.

Hope this helps