You shall not pass!!! Frequency Filter 15/24/31khz?

Everything Emulator related
Forum rules
ArcadeOtaku forum introduction & rules
User avatar
Shadolf
Posts: 249
Joined: November 6th, 2014, 12:20 pm
Location: South Germany

You shall not pass!!! Frequency Filter 15/24/31khz?

Postby Shadolf » November 24th, 2016, 6:48 pm

I´ve build a new GroovyMAME PC with CRT-Emudriver and the last problem I have to solve is, how can I ensure that only the "healthy"-frequencys reach my monitor.
The PC gives out a resolution of 1024x768 during the boot and there is no option to change this.
Is there any "security"-device that checks the frequencies and let only those pass that one sets with a switch or jumpers?
So that there are 3 switches, one for each, 15khz, 24khz and 31khz and only the switched frequencys go throught to the monitor.

I found the J-PAC from Ultimarc, but I´m not sure if this is what I´m looking for.
At the product description it says:
1. Custom microcontroller only allows sync signals to be sent to the monitor if they are in the correct range that the monitor is designed for. Avoids driving the monitor with a too-high horizontal sync rate which can damage some arcade monitors.
2. Sync circuitry also converts separate horizontal and vertical syncs into composite sync. Can handle both positive and negative vertical sync.

Point 1. I think is what I need, but point 2. is not I think. Isn´t it better to have seperate syncs over composite sync? I what to connect my PC to a Toshiba PF and also to Sony Trinitron TV´s with EURO-Scart.
Also is there any device that has that sync filter funktion only. I mean something with a lower price tag then the J-PAC, since I need a few of those devices?
User avatar
trev1976
Posts: 718
Joined: March 30th, 2009, 7:17 pm
Location: Southampton

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby trev1976 » November 24th, 2016, 8:57 pm

Jpac protect's your 15khz screen from 31khz
Check out my "1cc" YouTube Channel
YouTube
User avatar
Shadolf
Posts: 249
Joined: November 6th, 2014, 12:20 pm
Location: South Germany

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby Shadolf » November 24th, 2016, 9:24 pm

Yeah I see, but is there another cheaper option? I only need this function, don´t really need that other stuff that the J-Pac does.
User avatar
cools
Armed Police Buttrider
Posts: 13452
Joined: August 17th, 2008, 4:49 pm
eBay: hordarian
Initials: CLS
Location: Wales, United Kingdom
Contact:

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby cools » November 24th, 2016, 9:26 pm

Have you flashed your Radeon BIOS with ATOM-15?
Image
User avatar
Shadolf
Posts: 249
Joined: November 6th, 2014, 12:20 pm
Location: South Germany

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby Shadolf » November 25th, 2016, 3:55 pm

No, I have not flashed the Atom-15 Bios to my card.
I just have to check if it works with my HD6450.
As I read at geedorah, it would work when I only activate the 15khz and 31khz:

"- If both 15 and 31 kHz ranges are selected, then 640 x 480 will be calculated in the 31 kHz range, to avoid using an interlaced mode.
- If both 25 and 31 kHz ranges are selected, then 1024 x 768 will be calculated in the 25 kHz range, as interlaced, to avoid requiring big black borders."

And it would only work for my Thoshiba PF as the Trinitrons would need a new Bios flash for 15khz only.
I would like to be able to swich between frequencys fast, as i´d like to play NAOMI games in 31khz mode.
User avatar
cools
Armed Police Buttrider
Posts: 13452
Joined: August 17th, 2008, 4:49 pm
eBay: hordarian
Initials: CLS
Location: Wales, United Kingdom
Contact:

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby cools » November 25th, 2016, 7:00 pm

Flash it for 15k. GroovyMAME and CRT_Emudriver will still work as normal, but those scary boot screen resolutions will only be 15k and this will work on the Sony and the Tosh
Image
User avatar
cools
Armed Police Buttrider
Posts: 13452
Joined: August 17th, 2008, 4:49 pm
eBay: hordarian
Initials: CLS
Location: Wales, United Kingdom
Contact:

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby cools » November 25th, 2016, 7:01 pm

All it does is reprogram the VESA tables used when no proper driver is active.
Image
User avatar
Shadolf
Posts: 249
Joined: November 6th, 2014, 12:20 pm
Location: South Germany

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby Shadolf » November 25th, 2016, 8:15 pm

Ahhh, thats nice. Thanks cools.
What just came to my mind, what is in case I connect a 31khz only CRT to the flashed graphicscard? Would the 15khz do any harm?
I assume for a LCD multisync the 15khz signal is no problem?!
User avatar
cools
Armed Police Buttrider
Posts: 13452
Joined: August 17th, 2008, 4:49 pm
eBay: hordarian
Initials: CLS
Location: Wales, United Kingdom
Contact:

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby cools » November 25th, 2016, 8:29 pm

Nah, it'll be fine. The LCD is a mixed bag, may work.
Image
User avatar
keropi
Posts: 174
Joined: January 14th, 2016, 6:04 pm
eBay: sainshov
Location: Greece

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby keropi » November 25th, 2016, 8:37 pm

trev1976 wrote:Jpac protect's your 15khz screen from 31khz


Weird thing is that if I jumper my jpac to 15khz-only or 15khz+31khz compatibility option I don't see any difference with my POLO28" cab... in both cases I get garbled output like 31khz just pass to the chassis. This happens with 2 jpacs in 2 different POLO28" setups... maybe it's a chassis limitation or something
User avatar
Shadolf
Posts: 249
Joined: November 6th, 2014, 12:20 pm
Location: South Germany

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby Shadolf » November 25th, 2016, 10:34 pm

Ok, now i flashed it with 15 24 and 31khz enabled for use with the Tosh.
Now when I boot up with an Multisync LCD (max. resolution 1600x1200) plugged in, I can see a squeezed picture on the upper half and a blackwhite flickering on the lower half of the screen. The OSD says 600x800@59,9Hz. What kind of resolution is this? Looks like a vertical resolution. Will test it now at the Tosh, I hope everything goes right :oops:

EDIT: So I just tested it and it doesn´t look healthy to me. The picture is over the whole screen, not just on the upper half like at the LCD. But it´s no clear image, it´s like a shifted double or multiimage that flickers. Will this really do no harm?
I will test now the 15 and 31khz.

EDIT2: Tested 15 and 31khz without 24 and now the image at the Toshiba is stable and clear, although a little small. This looks way better. At the LCD it now shows a higher resolution (1280x....), but image is still only on the upper half. Lower half flickers. So now the test with the 15khz only ;)

EDIT3: Ok, so 15khz only works with the Toshiba. But I switched back to the 15/31 Bios cause the boot sequence looks much better and I can access the boot menu, that was not possible with 15khz only because the screen was just black when pressed F11. So the last question for me is, does it bad to the monitor when the image flickers wildly and such things that happened with the 15/24/31 Bios?
User avatar
cools
Armed Police Buttrider
Posts: 13452
Joined: August 17th, 2008, 4:49 pm
eBay: hordarian
Initials: CLS
Location: Wales, United Kingdom
Contact:

Re: You shall not pass!!! Frequency Filter 15/24/31khz?

Postby cools » November 26th, 2016, 7:48 am

Enabling 24k means your PC is likely to select a medium res on boot up. I use 24/31k with mine so it has 1024x768 available in 24k for the UEFI BIOS screens.
Your LCD probably won't display a 24k screen. Your Sony won't and could potentially be damaged by it, so best to avoid it.
The results at 15k only shows that its doing the job I was recommending it for, but that your PC BIOS requires a higher resolution than what is available.
Image

Return to “Emulation Q&A”



Who is online

Users browsing this forum: No registered users