The NEW Build Your Own Arcade Controls

Main => Monitor/Video Forum => Topic started by: Arroyo on January 16, 2019, 11:20:43 am

Title: Sync and Arcade monitor questions
Post by: Arroyo on January 16, 2019, 11:20:43 am
So I’m new to Arcade monitors.  Been getting a CRT TV up and running using CRT-Emulation driver and GroovyMame and it looks great, but I bought the Arcade monitor for the wide range of vertical frequency flexibility and have questions.

Mostly it’s two three questions:

1.). Do I need to amplify the signals coming from my PC to the Arcade monitor as implied on the J-PAC webpage and from other places I’ve read?
(https://uploads.tapatalk-cdn.com/20190116/b32a80ee9bd71a9922bfd457a4f728c7.jpg)

2.) The Sync markings on the chassis and the specs of the monitor are confusing to me:
(https://uploads.tapatalk-cdn.com/20190116/ce78c2d72595c80f1b5795724096ebbe.jpg)(https://uploads.tapatalk-cdn.com/20190116/3ba2bd507453b76da7871b17ee65d2b1.jpg)

It seems that I have a 5 pin connection which would imply that I need to feed it Composite Sync?  If that’s true is the best way to do that is by combing both lines with 1kohm resistors each and join them together in “T” connector?  I’ve read about other methods for combing syncs but was hoping experienced folks could comment.

3.) How do I know if the chassis requires an Isolation Transformer?  It came with an standard wall plug, but I have read numerous places that say most chassis should have an Isolation Transformer.  If so is there a recommended one to buy?  I do see this one a lot:  here (https://www.ebay.com/itm/Arcade-Game-CRT-Monitor-Isolation-Transformer-13-19-25-27-29/121641605397?_trkparms=aid%3D333200%26algo%3DCOMP.MBE%26ao%3D1%26asc%3D20171012094517%26meid%3D479eb41c9fa84e2aadcc94bc95f2b5ef%26pid%3D100008%26rk%3D1%26rkt%3D12%26sd%3D120966957215%26itm%3D121641605397&_trksid=p2047675.c100008.m2219)


Thanks in advance.
Title: Re: Sync and Arcade monitor questions
Post by: buttersoft on January 16, 2019, 06:32:59 pm
1. You will almost certainly need a video amplifier. A J-Pac is an excellent choice, and comes prebuilt and has sync protection. A THS7314 or 7316 is only a dollar, but you have to build a circuit.

2. It looks like the chassis will take either composite sync or separate H- and V-sync. Crt_emudriver 2.0 beta 13 and up will output composite sync for you over pin 13 of the VGA connector. (This pin is normally used for H-sync).  I've seen you posting in the GM forum, so i presume you're using Calamity's driver? You may need to wire up a cable, of course.

3. Probably not, unless you're getting video noise or interference issues. New universal chassis tend to be free-voltage as yours is listed as (90-260VAC input) and won't need isolation. With these chassis you can normally also choose to connect mains earth or not, depending on what gives the best result, though normally it makes no difference.
Title: Re: Sync and Arcade monitor questions
Post by: Arroyo on January 16, 2019, 08:24:52 pm
1. You will almost certainly need a video amplifier. A J-Pac is an excellent choice, and comes prebuilt and has sync protection. A THS7314 or 7316 is only a dollar, but you have to build a circuit.

2. It looks like the chassis will take either composite sync or separate H- and V-sync. Crt_emudriver 2.0 beta 13 and up will output composite sync for you over pin 13 of the VGA connector. (This pin is normally used for H-sync).  I've seen you posting in the GM forum, so i presume you're using Calamity's driver? You may need to wire up a cable, of course.

3. Probably not, unless you're getting video noise or interference issues. New universal chassis tend to be free-voltage as yours is listed as (90-260VAC input) and won't need isolation. With these chassis you can normally also choose to connect mains earth or not, depending on what gives the best result, though normally it makes no difference.


Thanks buttersoft.  I had the question about the amplification because nipsmg recently did something similar and wasn’t using amplification so that had me scratching my head.

Do you think the pin labeled E is Vertical sync then? Can I possibly damage the monitor by tryin to feed it vertical sync, or best to just try Composite sync through CRT emulation driver on the “Sync” (appears to be horizontal) line?

Good to know on the isolation transformer, thanks!

EDIT:  Well duh, E must be for earth or ground.  It looks like there is actually 6 contacts next to the 5 pins, and the labels of H and V show up.  Still not sure what the difference between the 5 pins and 6 contacts but seems like there would be a way to acces the 6 contacts for a direct H and V sync feed.....anyone know for sure?

Title: Re: Sync and Arcade monitor questions
Post by: big10p on January 17, 2019, 06:19:05 am
Looking at the specs, your monitor just takes composite sync on the S pin (usually ouput via the hsync line, as buttersoft says). The separate hsync/vsync connections are optional, so probably aren't even connected to anything on your chassis.

Interestingly, the specs on the website selling these monitors say "Use The Double Video Amplifier Circuit, Provided Better Picture Quality", which seems to suggest it has a built-in amp, but I'm not sure, TBH.
Title: Re: Sync and Arcade monitor questions
Post by: Arroyo on January 17, 2019, 08:17:54 am
Looking at the specs, your monitor just takes composite sync on the S pin (usually ouput via the hsync line, as buttersoft says). The separate hsync/vsync connections are optional, so probably aren't even connected to anything on your chassis.

Interestingly, the specs on the website selling these monitors say "Use The Double Video Amplifier Circuit, Provided Better Picture Quality", which seems to suggest it has a built-in amp, but I'm not sure, TBH.

Thanks big10p.

So if I’m going to make my own VGA connector I was thinking of using this:

 https://www.amazon.com/dp/B074V5SJBL/ref=cm_sw_r_sms_c_api_i_N5hqCbTVMN4V9 (https://www.amazon.com/dp/B074V5SJBL/ref=cm_sw_r_sms_c_api_i_N5hqCbTVMN4V9)

It seems that there is some pinout diagrams that may be mirror images of each other?:
(https://uploads.tapatalk-cdn.com/20190117/c99689211f1c696222b5ddc679686306.gif)
(https://uploads.tapatalk-cdn.com/20190117/0fd1bbf9fe87b2e650d4a5b931f07186.jpg)

I assume one is female side and one is male side.  Anyone know which is which?  Lastly am I correct that I will need to run all of the grounds (pins 6-10) to pin 5 inside the VGA head like in the diagram?
Title: Re: Sync and Arcade monitor questions
Post by: nipsmg on January 17, 2019, 08:54:27 am
Arroyo,

That is exactly what I used on my arcade cabinet, that same one from amazon. (Ignore the gender changer in the end, I accidentally ordered male).

(https://i.imgur.com/DGdKpbc.jpg)

I believe the bottom picture is looking from the back, but it doesn’t matter, the breakout board is numbered with PIN numbers.  You do not need to tie 5-8 together.  All you need is 1,2,3 (RGB), 5 (gnd). 13 and 14 (syncs).  My chassis has pins for both syncs, so I pumped them both in.

Make sure you have a good VGA cable.  I think I posted it here, but I had a bad cable and I thought my syncs were off.  Turns out the cable just sucked.  Swapped it out, perfect picture.
Title: Re: Sync and Arcade monitor questions
Post by: Arroyo on January 17, 2019, 09:22:54 am
Arroyo,

That is exactly what I used on my arcade cabinet, that same one from amazon. (Ignore the gender changer in the end, I accidentally ordered male).

(https://i.imgur.com/DGdKpbc.jpg)

I believe the bottom picture is looking from the back, but it doesn’t matter, the breakout board is numbered with PIN numbers.  You do not need to tie 5-8 together.  All you need is 1,2,3 (RGB), 5 (gnd). 13 and 14 (syncs).  My chassis has pins for both syncs, so I pumped them both in.

Make sure you have a good VGA cable.  I think I posted it here, but I had a bad cable and I thought my syncs were off.  Turns out the cable just sucked.  Swapped it out, perfect picture.

Thank you nipsmg!!  Good to hear from someone who has gone through the experience recently.
Title: Re: Sync and Arcade monitor questions
Post by: buttersoft on January 17, 2019, 05:38:33 pm
Just make sure you don't short VGA pin 9 to one of the ground lines like seems to be happening in one of those plug schematics above. Pin 9 is +5V!
Title: Re: Sync and Arcade monitor questions
Post by: Arroyo on January 17, 2019, 05:59:02 pm
Just make sure you don't short VGA pin 9 to one of the ground lines like seems to be happening in one of those plug schematics above. Pin 9 is +5V!

Good call, must’ve been lazy work on the second graphic.