Vertical PC CRT build?

[MiteWiseacre]

Hi all,
Tying to do research but coming up a little dry.
I am looking into my second build and considering a Super Contra or contra style cab, vertical screen.
I might be able to score  a decent crt PC monitor. The question, is it advisable to use a comp monitor vertical? Will I ever get it to run SD? Scan line generator my only option?
Thanks

[Drnick]

No reason not to use a CRT PC Monitor on it's side, If you decase it then it might be a bit awkward depending on board configuration but I've never seen any issues.
Not sure what you mean by SD, without monitor specifications can't say what resolutions it will do, but I would expect at least 640x480 and probably 800x600.
You will automatically have scanlines if it is a CRT monitor.

[MiteWiseacre]

Thanks for the reply. Regarding SD I was meaning can I display 240p on one of these, what I understand is that 480 is as low as you can go, is that true?

[Mike A]

Just buy a 19 inch arcade CRT.

[MiteWiseacre]

Mike, that’s like $500 vs $20, I don’t think you realize how cheap I am. I do like the reuse type build more as well...

[Mike A]

Your information is bad. I bought a 25 inch arcade CRT is good working order for 150 bucks.

I have purchased about a dozen arcade CRTs in the past year. 200 bucks is the most I have paid. That was a special case.

[MiteWiseacre]

I will look into this, thanks. See my usual, retroactive is selling 15” crts.
Maybe I rethink my plans. 

[Mike A]

The advantage to using an arcade CRT is you can also easily use Arcade PCBs if you ever get the itch.

[Paradroid]

The advantage to using an arcade CRT is you can also easily use Arcade PCBs if you ever get the itch.

"... if you ever get the rich".

[leapinlew]

If you're using Mame with a PC - I'd suggest using a computer CRT. Arcade monitors are a pain when using mame and trying to switch between games with many different resolutions. Sure you can find an arcade monitor for a not unreasonable amount, but if you want the arcade monitor to have a VGA input - it gets more difficult to source and costly.

I'm not a purist, but I do enjoy a CRT over an LCD. If I'm using and LCD I prefer to use a scan line generator of some sort (software or hardware).

[Howard_Casto]

Hey here's some old school advice.... before you de-case the monitor put it in the approximate orientation that you want to mount it in and let it run for a while.  Some monitors won't work in certain orientations.... something about the degaussing I think. 

[MiteWiseacre]

Here’s another question I can’t quite figure, what ratio are these vertical screens? Are they all 4:3? I gather so far that a crt computer monitor is an improvement from LCD but not as great as a true arcade monitor. Bear in mind my last build was off a WEGA, I want to hit some more unique resolutions with this one.

[leapinlew]

Here’s another question I can’t quite figure, what ratio are these vertical screens? Are they all 4:3? I gather so far that a crt computer monitor is an improvement from LCD but not as great as a true arcade monitor. Bear in mind my last build was off a WEGA, I want to hit some more unique resolutions with this one.

Odds are you are only going to be playing 4:3 in vertical as the vast majority of vertical games are 4:3.

[Zebra]

I think using a PC crt monitor for mame is a waste of time and energy. If you care about making old 240p arcade games look nice and authentic then you'll never be happy with a PC crt. If you don't care about authenticity then you'll have a far easier time mounting an LCD monitor vertically.

Either way, you'd have to use scaling and mame shaders. The majority of crt PC monitors won't sync to anything lower than 31khz so the only way to output 240p would be to use 120hz but even then, the image would be terrible without shaders. i found it no better than using an LCD.

As an FYI, vertical arcade monitors come with a special vertical mounting frame. Without the right frame, mounting a de-cased crt pc monitor on it's side is no easy task. You can't rest it on it's neck board...

I have no issue with trying to save a buck but you're overlooking a far better and equally cheap option. You can get an SD CRT TV for $10 on ebay or Craigslist. It will look significantly better than a crt pc monitor. It's night and day. This is mame running on a free mid 90's Trinitron I picked up:

[leapinlew]

So there you have it OP - a couple different perspectives.

It all comes down to you and your preferences. Go figure it out and let us know.

[yotsuya]

I’d rather use a PC monitor than an LCD (and I have, in a vertical cab I built).

[Trnzaddict]

The only problem by picking up a curb or Craigslist TV is it would have to have its precious component inputs which can be a pain in the ass.


The Trinitron you posted Zebra looks like maybe a KV-27V45. They are perfect for an arcade project due to the curved tube and excellent picture BUT in that era I t is almost impossible to find a curved 90’s trinitron with component inputs. They all seem to have either composite or s-video.

Before I read up on CRT emu driver I picked up 2 of these out of haste for free but they’re now sitting in my basement because one has only composite and one has s-video.

However if you get an Extron Emotia You can get decent 240p out of s-video but you may run into problems with overscan and underscan with Mame.

And the last thing you could is rgb mod a CRT but 240 pixels isn’t worth getting thrown across the room for. My opinion.

[Zebra]

The only problem by picking up a curb or Craigslist TV is it would have to have its precious component inputs which can be a pain in the ass.


The Trinitron you posted Zebra looks like maybe a KV-27V45. They are perfect for an arcade project due to the curved tube and excellent picture BUT in that era I t is almost impossible to find a curved 90’s trinitron with component inputs. They all seem to have either composite or s-video.

Before I read up on CRT emu driver I picked up 2 of these out of haste for free but they’re now sitting in my basement because one has only composite and one has s-video.

However if you get an Extron Emotia You can get decent 240p out of s-video but you may run into problems with overscan and underscan with Mame.

And the last thing you could is rgb mod a CRT but 240 pixels isn’t worth getting thrown across the room for. My opinion.

The one in the pic is a flat crt Trinitron with just svideo (I've never seen a curved Trinitron). It was used with CRT EMU drivers with groovymame with a Jrok to convert RGB from the PC to svideo. You can also find Namco rgb to NTSC converters on ebay for very little cash. It's what they used in their rear projection cabs.

If the choice is between playing on a 15khz TV with games at native res and refresh rates via svideo or a 31khz minimum PC crt monitor, you are much better off with the TV. It's not even close.

The most commonly available Trinitron tvs now are the late model FS line with the silver case. Almost all of them have component video. They aren't hard to find on ebay and Craigslist.

[Trnzaddict]

The only problem by picking up a curb or Craigslist TV is it would have to have its precious component inputs which can be a pain in the ass.


The Trinitron you posted Zebra looks like maybe a KV-27V45. They are perfect for an arcade project due to the curved tube and excellent picture BUT in that era I t is almost impossible to find a curved 90’s trinitron with component inputs. They all seem to have either composite or s-video.

Before I read up on CRT emu driver I picked up 2 of these out of haste for free but they’re now sitting in my basement because one has only composite and one has s-video.

However if you get an Extron Emotia You can get decent 240p out of s-video but you may run into problems with overscan and underscan with Mame.

And the last thing you could is rgb mod a CRT but 240 pixels isn’t worth getting thrown across the room for. My opinion.

The one in the pic is a flat crt Trinitron with just svideo (I've never seen a curved Trinitron). It was used with CRT EMU drivers with groovymame with a Jrok to convert RGB from the PC to svideo. You can also find Namco rgb to NTSC converters on ebay for very little cash. It's what they used in their rear projection cabs.

If the choice is between playing on a 15khz TV with games at native res and refresh rates via svideo or a 31khz minimum PC crt monitor, you are much better off with the TV. It's not even close.

The most commonly available Trinitron tvs now are the late model FS line with the silver case. Almost all of them have component video. They aren't hard to find on ebay and Craigslist.

How long have those jrok transcoders been around for? I asked here specifically in the Groovymame forum a while back if s-video would work with crt_emudriver and I got the typical “Nope. You need component.”

I’m kind of pissed because I really wanted to enjoy crt_emudriver on a curved tube as that was the crt I grew up on. I settled on a flat screen tube because that’s all I could find with component and being that 90% of my arcade memories were of badly maintained monitors and I used RF and composite at home component is not a visual necessity.

Even the guys in the Shmup forums said in order to get 240p from pc to S-video is a scan converter like the Extron Emotia but I would be unable to use crt emudriver as it only accepts 640x480 to downscale.

[Zebra]

The only problem by picking up a curb or Craigslist TV is it would have to have its precious component inputs which can be a pain in the ass.


The Trinitron you posted Zebra looks like maybe a KV-27V45. They are perfect for an arcade project due to the curved tube and excellent picture BUT in that era I t is almost impossible to find a curved 90’s trinitron with component inputs. They all seem to have either composite or s-video.

Before I read up on CRT emu driver I picked up 2 of these out of haste for free but they’re now sitting in my basement because one has only composite and one has s-video.

However if you get an Extron Emotia You can get decent 240p out of s-video but you may run into problems with overscan and underscan with Mame.

And the last thing you could is rgb mod a CRT but 240 pixels isn’t worth getting thrown across the room for. My opinion.

The one in the pic is a flat crt Trinitron with just svideo (I've never seen a curved Trinitron). It was used with CRT EMU drivers with groovymame with a Jrok to convert RGB from the PC to svideo. You can also find Namco rgb to NTSC converters on ebay for very little cash. It's what they used in their rear projection cabs.

If the choice is between playing on a 15khz TV with games at native res and refresh rates via svideo or a 31khz minimum PC crt monitor, you are much better off with the TV. It's not even close.

The most commonly available Trinitron tvs now are the late model FS line with the silver case. Almost all of them have component video. They aren't hard to find on ebay and Craigslist.

How long have those jrok transcoders been around for? I asked here specifically in the Groovymame forum a while back if s-video would work with crt_emudriver and I got the typical “Nope. You need component.”

I’m kind of pissed because I really wanted to enjoy crt_emudriver on a curved tube as that was the crt I grew up on. I settled on a flat screen tube because that’s all I could find with component and being that 90% of my arcade memories were of badly maintained monitors and I used RF and composite at home component is not a visual necessity.

Even the guys in the Shmup forums said in order to get 240p from pc to S-video is a scan converter like the Extron Emotia but I would be unable to use crt emudriver as it only accepts 640x480 to downscale.

There is a lot of people offering bad advice on the internet, especially of forums like Shmups where the standard is very low. I'm surprised about the groovymame forum on this site though. I got a lot of quality help from those guys.

Anyway, Jroks have been around for years. I got mine at least 5 years ago and it's certainly not the only transcoder around. There have been plenty of devices that convert RGB color to NTSC without changing the resolution or refresh rate. Sometimes it's just a case of using the right search terms as they don't all call themselves "transcoder". The ones used in Namco cabs are referred to as RGB to NTSC converter.

https://www.ebay.com/itm/Namco-America-RGB-NTSC-Converter-Rev-A/232694694980?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D20131231084308%26meid%3De780d661c0944bd2a7294ff6038d7c0e%26pid%3D100010%26rk%3D1%26rkt%3D12%26sd%3D133217226348%26itm%3D232694694980%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100010.m2109

I just happen to favor the Jrok devices as they are custom made for arcade games. They have pots to adjust the RGB balance and they do a nice job with both mame and real PCBs. They have actual s-video out ports too while some are a little more DIY. You find them in some superguns.

I'm thinking of buying a component to rgb converter (for my Wii) from the guy that makes these. I don't know if they are good but it's another option to look at:

https://www.ebay.com/itm/RGB-VGA-to-NTSC-S-video-and-composite-transcoder-encoder/174130431769?hash=item288afb8719:g:560AAOSw9MRd-0Cl


The Extron scan converters like the Emotia are entirely different in what they do and should be avoided for this purpose. Crt emu with groovymame does a far better job of outputting 240p. Downscalers produce a softer and generally inferior image. I bought an Emotia and an Ultracade UVC to try before finding groovymame. They both suck. Their only value is for playing old games on consoles with no option to output native resolutions. I use my UVC to convert Daytona on the PS3 from 480p to 384p.

[leapinlew]

There is a lot of people offering bad advice on the internet,

Preach!

One time a guy suggested that using a PC CRT for MAME was a waste. 

[MiteWiseacre]

Thanks guys, plenty to consider. I think I will continue to plan in the winter months and then get at it in the spring if I can settle on someting.
I definately understand using a WEGA, that was my last build. Looking for a different idea, maybe even an old curved screen - try my hand at a RGB conversion...
Trying to find a proper arcade monitor up here is tough, I can get a 15" pretty reasonably - but I probably want a 19" don't I? seems a little small, leads me back to a television again.
I do have an extron, its very cool, but it only does 480i and thats ok but I moved on to standard res pretty quick.
Zebra, does that transcoder only output composit?
Been trying to find Contra cabinet plans online with no luck, probably not a dificult style to copy, but I'm tossing around the idea of a reproduction build. Anyone have a link?

[MiteWiseacre]

I’d rather use a PC monitor than an LCD (and I have, in a vertical cab I built).

You have a build thread for this? Maybe a pic?

[Zebra]

Thanks guys, plenty to consider. I think I will continue to plan in the winter months and then get at it in the spring if I can settle on someting.
I definately understand using a WEGA, that was my last build. Looking for a different idea, maybe even an old curved screen - try my hand at a RGB conversion...
Trying to find a proper arcade monitor up here is tough, I can get a 15" pretty reasonably - but I probably want a 19" don't I? seems a little small, leads me back to a television again.
I do have an extron, its very cool, but it only does 480i and thats ok but I moved on to standard res pretty quick.
Zebra, does that transcoder only output composit?
Been trying to find Contra cabinet plans online with no luck, probably not a dificult style to copy, but I'm tossing around the idea of a reproduction build. Anyone have a link?

If you are asking about the Jrok then there was two options when I got mine. The one I chose has Component, Svideo, Composite and RGB pass-through outputs:






There was also a smaller and cheaper one which just had Svideo and Composite. Using one with a curved tube Sharp CRT would be a very decent low cost option imo. You can then decide if you're happy with the image or if you want to invest some time in an RGB mod. Just being able to play games at native res and refresh rate makes a huge difference to the experience and Groovymame saves an enormous amount of time by selecting the right settings for you.

If you're asking about other transcoders, I don't know any more than what is advertised.

I think your instinct on screen sizes are right. Obviously you can play on any monitor but if you're trying to recreate the arcade experience then a larger screen is needed. I have 19", 23.5", 25" and 27" crt monitors here. 25" is the sweet spot for most games. I think 19" is good for a vertical games cab. I wouldn't go any smaller though.

[Paradroid]

maybe even an old curved screen - try my hand at a RGB conversion...

RGB mods are easier than they've ever been thanks to the wealth of guides and working examples out there these days.

[MiteWiseacre]

I’ve had this little baby n my garage for some time. Bought it new, years ago and hardly used it, the picture doesn’t look too bad surprisingly. Modding a 20” diamond perhaps?

[MiteWiseacre]

Not sure if I should take this over to the project announcement forum, but I’m going to document this in case it’s of some help to others in the future.
Diamond Vision DTV2822, made in China uses Mitsubishi Chips, I think it’s the same as many cheap house-brand TVs from mid 2000’s (cannot remember when I bought it but think 2008)
These are the data sheets I found that match most closely: 

M37150M8-111FB (the osd chip)
https://html.alldatasheet.com/html-pdf/132945/RENESAS/M37150M8-XXXFP/301/1/M37150M8-XXXFP.html
M61266 (Jungle Chip) and the closest I’ve found:
https://html.alldatasheet.com/html-pdf/104421/MITSUBISHI/M61206FP/1208/2/M61206FP.html

[Zebra]

Good for you. You'll appreciate the extra effort every time you play if you do it right. Playing arcade games at their exact native refresh rate and res is just better.

Thanks to groovymame, you'll be able to spend a lot more time playing and far less messing around with shader settings trying to make it look like the arcades you remember.

[MiteWiseacre]

Thanks Zebra.
So I found the jungle is actually more likely this one:
https://html.alldatasheet.com/html-pdf/249291/RENESAS/M61283FP/295/1/M61283FP.html

From the closed caption IC there are points 33 (blanking), 34 R, 35 G, 36 B
The Blue for example goes through a path like this
#36 B - 110k Resistor - Handy unused connection hole- 0.1 uF Cap - #21 Blue In on the jungle
#33 - Diode - R132 - ground
 ..............   - #24 Fast Blanking
So I soldered in at the Handy Connection Hole with Blue and connected to the A/V outs which I disconnected from the circuit. I also took 5v (or so it’s labeled at the RF antenna) and ran through a switch that I connected to the point the diode was attached. The diode is pulled of on one end and run to the two position switch. Hopefully I can switch the blanking on and off, I think this is just for closed caption but maybe the OSD that I will need.
Those Handy connections are also perfect if I need to add a resistor to ground to the RGB inputs.

Please chime in if you see errors in my plan, not able to test it yet need to make a cable first.

[MiteWiseacre]

Ok.. so it kinda works, gives me hope.
Made up a cable that goes from VGA to RCAs, learned that I need to combine the H sync and V sync. Hopefully that will fix the vertically rolling screen.
It seems, from what I’m reading, I also have to switch or remove the osd RBG (thought I could get away with leaving it). I’m getting an image but it’s got bright areas of red blue and green, and where other colours should be it’s black.

[MiteWiseacre]

Made some progress, build a little board with a female VGA port and a pot on the H & V sync lines. Combining the two syncs and dialling it down got the screen steady, no more rolling!
Finding that I only get .25v from the vga RGB, I think it needs to be .7v.. I presume this is why the black areas on the screen, white text looks perfect.  Tried to 75ohm to ground method, this resulted in no picture at all.   I do have 1uF caps in line with the RGB, will bigger caps help boost the signal?

[Zebra]

I recommend that you spend $10-$15 on a used Extron RGB interface. It will solve all your sync and rgb termination related issues with the flick of a switch. Some even have horizontal and vertical image shift controls which would be very useful on a TV with no easy access to these.

The interface will output on BNC connectors which can be easily change to RCA with $2 BNC to RCA adapters (or you could install BNC ports on your TV). The extron interface will be far more reliable when combining H and V sync to C sync.

The VGA port on a PC GPU should already be the correct voltage for consumer hardware. If you are adding extra resistors, make sure they are needed first. I.e check if the image is too dark or too bright.
When I use the wrong rgb cable for my arcade monitors (I.e. One with resistors that weren't needed) I have to set the contrast and brightness to full to see anything on-screen...

Sounds like you're nearly there on the mod. Make sure you post pics when you're done.

[MiteWiseacre]

Thanks for the encouragement, I really hope I can sort this out. My experimenting today didn’t get me much closer, going to see if anyone on the shmups forum has advice.
The converter might do it, but not sure if I’ve inserted in the correct spot.

[Zebra]

It certainly helps to know what the issue is before investing in solutions. You should get an Extron RGB interface regardless though. It's just super helpful for this kind of project. It gives you an LCD display to confirm you are outputting the correct res and refresh rates. It has switches to go between .75ohm and 1kohm termination and the ability to convert any type of sync to the kind you need.

There us just two potential sync related issues it won't solve. One is a signal that is out of range for the TV. Nothing will help with that. Just make sure to use something close to the NTSC broadcast standard as possible for testing. The other is that some monitors require "clean sync" so a sync cleaner is needed. The latter is unlikely when you are syncing on composite video though.

What makes you think you've connected the RGB signal to the wrong place? If you're getting an image then you most likely did it right (assuming it's not in black and white).

[MiteWiseacre]

Think it’s in wrong place because it seems like the signal needs boosted or isn’t mixing colours..
You make me think though, I’m outputting 15.7khtz arcade instead of regular ntsc, that’s worth playing with.

[Zebra]

Think it’s in wrong place because it seems like the signal needs boosted or isn’t mixing colours..
You make me think though, I’m outputting 15.7khtz arcade instead of regular ntsc, that’s worth playing with.

When I talk about outputting something close to the NTSC broadcast standard, I'm really saying to use a game that is close to 60hz 240p (or 480i). I.e. Not one of the 256 line 54hz games. The other parts of the spec like NTSC color are irrelevant for an rgb mod. You just want to make sure it's something you know your TV can sync to.

A weak signal or poor color is an unrelated issue. Sync problems manifest as a rolling image or no image at all.

I hate to say this but it sounds like you may have an unsolvable problem with your specific TV. Some TV's use that digital TTL rgb for the on-screen display instead of analog rgb. You can boost the signal to TTL levels with a signal booster from Ultimarc but the old digital RGB was limited to 8 colors (or something like that). If this is the case, the OSD to RGB mod is a dead end.

Depending of how the TV is wired and where it's hot, you may be able to connect RGB lines directly to the neck board. Some of my arcade monitors are wired like this. You'd need someone with far more CRT experience than me to help with that. I've seen projects like that written up online though.

Another option could be to replace the chassis with one of the Universal arcade chassis off ebay. You just need to check if you have a compatible neck board / yoke n stuff.

Can you post a pic of the color problem?

[MiteWiseacre]

The 8 colour digital limit makes some sense, I only seem to get pure red, blue, green, yellow, white and black lots of black. If it’s a no go that’s alright, I can find another tv with a known method fairly easily, I think.

[MiteWiseacre]

So I picked up a Toshiba 27a43 and made a quick and dirty go at a mod, the results are pretty damn nice! This monitor seems like it will put my WEGA to shame. Looks like this build just got a little thicker