Extron Crosspoint TTL Output Conversion

[Carpetman]

Hello all, It has been established that Extrons output on average a 510ohm, 5vpp sync signal that can be harmful to some equipment. But, no one to my knowledge has posted a way to convert the signal back to standard 75ohm sync. If someone has an Ocilloscope, could someone take a reading and find out the output Vpp while the Extron is under load? And also post the necsarry components to fix it if you are able. And please make it easy to understand for my sake, and the sake of anyone else reading this, so anyone can fix it. Thanks!

[mvsfan]

how about the sync signal on the EXTRON MVX series?

[Carpetman]

Thanks for the reply, but a quick look at the manual for the MVX series shows the same output. Many people already have Crosspoints, so it'd be nice to attenuate their sync without buying another unit.

[mvsfan]

Actually I asked because i have an Mvx. i was wondering if its affected by the same issue.

[Carpetman]

Gotcha, I misunderstood

[jayde6]

Sorry if this posts twice, my browser was having issues. I knew about the voltage issue but hadn't heard there was an impedance one too. The manual for my Crosspoint XP300 84 HVA lists the output as 4.0-5.0v p-p, 75 ohms. Is it only certain models that output at 510? What model are you using?

[Carpetman]

Ok, I just saw a RetroRGB video where someone says putting a 470 ohm resistor on the sync output attenuates to 500mvpp !

[RottenToTheGore]

Ok, I just saw a RetroRGB video where someone says putting a 470 ohm resistor on the sync output attenuates to 500mvpp !

Mind linking to that video?

[philexile]

Hello,

Are you using your Crosspoint with a consumer TV, Framemeister, or PVM/BVM? If it's a BVM, then there is no reason to worry about TTL sync. It states in the manual that accept sync up to 8vpp.

I assume PVMs are OK too.

[Carpetman]

Sorry if this posts twice, my browser was having issues. I knew about the voltage issue but hadn't heard there was an impedance one too. The manual for my Crosspoint XP300 84 HVA lists the output as 4.0-5.0v p-p, 75 ohms. Is it only certain models that output at 510? What model are you using?

I have an Extron Crosspoint 300 1616 with the ADSP feature, which as far as I know, boosts the input sync to 510 ohm, 5vpp TTL. So maybe ones that dont have the ADSP are fine? I'm no expert on these, so I can't be certain.

[Carpetman]

Ok, I just saw a RetroRGB video where someone says putting a 470 ohm resistor on the sync output attenuates to 500mvpp !

Mind linking to that video?

Sure! here you go.
https://youtu.be/ynZyvbCyKIA

[Carpetman]

Hello,

Are you using your Crosspoint with a consumer TV, Framemeister, or PVM/BVM? If it's a BVM, then there is no reason to worry about TTL sync. It states in the manual that accept sync up to 8vpp.

I assume PVMs are OK too.

I'm actually outputting to several devices, including the Framemeister. I'm also using a Mitsubishi Megaview that can handle TTL. Again, I just wanted the information available so anyone can make it usable for their devices.

[mvsfan]

My Extron is going to be running through a scart to component converter csy-2100. do i still have to worry about it?

its going to a wega tv.

[jayde6]

Sorry if this posts twice, my browser was having issues. I knew about the voltage issue but hadn't heard there was an impedance one too. The manual for my Crosspoint XP300 84 HVA lists the output as 4.0-5.0v p-p, 75 ohms. Is it only certain models that output at 510? What model are you using?

I have an Extron Crosspoint 300 1616 with the ADSP feature, which as far as I know, boosts the input sync to 510 ohm, 5vpp TTL. So maybe ones that dont have the ADSP are fine? I'm no expert on these, so I can't be certain.

Hmm, mine has adsp as well, I know some models let you turn it off. Mine does not though, or the manual isn't clear on how to.

[cr4zymanz0r]

This is what I see in the Extron Crosspoint manuals for Sync:
Sync
Input type ..................................... RGBHV, RGBS, RGsB, RsGsBs
Output type .................................. RGBHV, RGBS, RGsB, RsGsBs (follows input)
Input level ..................................... 0.5 V to 5.0 Vp-p, 4.0 Vp-p normal
Output level .................................. AGC to TTL: 4.0 V to 5.0 Vp-p, unterminated
Input impedance .......................... Inputs 1 to 4: 75 or 510 ohms, switchable
Inputs 5 to 8, 12, or 16: 510 ohms
Output impedance ...................... 75 ohms
Max input voltage ....................... 5.0 Vp-p
Max. propagation delay .............. 30 ns
Max. rise/fall time ....................... 4 ns
Polarity .......................................... Positive or negative (follows input)

I've been using my Extron switch for close to a year I think with no issues monitored on my XRGB3 and PVM (though it's usually only hooked to the Extron for testing), however I don't know of it's coincidence or not that my Sony Trinitron started having issues shortly after I RGB modded it. Modded it around the same time I got the Extron setup, and I'm feeding the sync output from the Extron into AV3's composite input jack on the Trinitron, then I started getting this issue on bright screens (was doing it on non-RGB inputs as well): https://youtu.be/aFuMB-ZebCg
At first it was just the first few minutes after I powered the TV on, but now it does it nearly all the time. Not sure if it's related or just a really bad coincidence.

I've made custom break-out boxes and such for my entire setup to use RCA connectors. Does anybody know of any tin RCA passthrough plus like this http://www.earlybirdsavings.com/picture ... ngle-0.jpg , except not right angle and easy to open so I could just solder in a 470 ohm resistor? That would make easier so I don't have to install it directly in some of my output breakout boxes, thus making them incompatible with non-Extron setups.

[Guspaz]

PVMs are designed to handle TTL sync. The Framemeister isn't, I don't know about the XRGB-3.

For example, taken from the data sheet of my PVM-14L2, ext sync is listed as:

4.0 Vp-p ± 6 dB, sync negative, usable tri-level sync signal 0.6 Vp-p ± 6 dB

Unless I'm mistaken, that means it's rated to handle anything from 2.0 to 8.0 Vp-p for TTL, and anything from 0.3 Vp-p to 1.2 Vp-p for 75ohm.

[Woozle]

I'm using a crosspoint to feed my OSSC on the vga port, is the VGA port TTL compatible?

[Guspaz]

From the OSSC documentation:

AV3 (VGA)

VGA/HD-15 input supports video in RGBHV, RGBS (pin 13), RGsB and YPbPr formats. RGBHV and RGBS modes require clean TTL-level sync signals and cannot extract sync from composite/luma. VGA input is best suited for high-quality input sources as video LPF functionality is limited (SCART and Component inputs are routed through a dedicated LPF chip). Therefore, it is generally recommended to connect older consoles and arcade boards to other inputs.

[Carpetman]

PVMs are designed to handle TTL sync. The Framemeister isn't, I don't know about the XRGB-3.

Not the most official source, but the fellow who said to put the resistors on the sync signal also tested a XRGB-3 input, and said it is high impedance.

[cr4zymanz0r]

BTW, if anyone has done a mod on a consumer CRT to give it RGB input and are using a composite (or probably any) input to feed it sync, the output of the Extron Crosspoint switches with sync processing is BAD.
I had been having this issue on my on my Trinitron for quite a few months now: https://youtu.be/aFuMB-ZebCg

It's mostly prevalent on brighter screens, especially mostly white screens like in the video (it was even doing it on non RGB sources as well). I've barely used it for months due to the issue, it has gotten worse, and assumed it was just dying and maybe needed to be recapped. After seeing this thread and other things talking about improbably attenuated csync signals, that made me wonder about the Trinitron.

Over the weekend I unplugged sync from the CRT, immediately tested and it still had the same issue. (Sync remained unplugged until) today I was telling my wife about how i'm just considering throwing it away because of the issue, she asked what it was doing, so I went to show her using gamecube with a component cable.....then it barely had the issue at all and worked fine after 5 sec. Of course I'll need to due further testing to see if it'll pretty much remain gone (I hope there wasn't permanent damage), but right now I'm trying to figure out an elegant way to get a 470 ohm resistor on the sync line going to it. I don't want to put it in the TV because I'd like it to work with non-Extron syncs as well (I also use RCA cables for all my RGBs+audio cabling, so there's not SCART cable hood to put it in).

[jayde6]

Has anyone done any measurements yet. The manual for the crosspoints listed in this thread all say that they are outputting 75ohm sync, which should be what's preferred for most applications right?

If that's true then it's just too much voltage right?

Happy to be corrected if I'm misunderstanding. Still trying to wrap my head around all this sync stuff.

[Carpetman]

Sorry if this posts twice, my browser was having issues. I knew about the voltage issue but hadn't heard there was an impedance one too. The manual for my Crosspoint XP300 84 HVA lists the output as 4.0-5.0v p-p, 75 ohms. Is it only certain models that output at 510? What model are you using?

Has anyone done any measurements yet. The manual for the crosspoints listed in this thread all say that they are outputting 75ohm sync, which should be what's preferred for most applications right?

If that's true then it's just too much voltage right?

Happy to be corrected if I'm misunderstanding. Still trying to wrap my head around all this sync stuff.

After researching a bit more into this, I decided just to call Extron directly and ask, so this is straight from the horses mouth. And this pertains to the 300 series of switchers with ADSP, so older swithers may be different. It would be best if someone still tested the ouputs just to confirm. I was wrong about the impedance being 510 ohms, it is indeed 75 ohms in and out. But the signal is converted to 5 Vpp on the H and V outputs via the ADSP. So if you are using RGsB, it is not being processed. That also goes for any other formats like S-Video and YPbPr, but I've never heard of TTL S-Video anyway . On newer Crosspoints there is a switch to turn the ADSP on and off, but the 300 series is hard wired in the signal, and therefore cannot be turned off. Hope this helps!

[jayde6]

Thanks for the great info! That does help out a lot. It's a shame it can't be turned off in older models, but at least now we know which ones to get for which kind of application. At least until someone figures out the best way to drop that voltage level to a safer range.

[Dochartaigh]

So I have an Extron Crosspoint Ultra 128 HVA matrix switcher, and there's little switches on the back. I'm assuming I want them set on 75 ohm? (instead of 510, and it says H Sync and V Sync below those switches).

[jayde6]

So I have an Extron Crosspoint Ultra 128 HVA matrix switcher, and there's little switches on the back. I'm assuming I want them set on 75 ohm? (instead of 510, and it says H Sync and V Sync below those switches).

510 is the default, the manual says you should switch them to 75 ohm if your sync signal is non-ttl greater than 5v p-p. It only applies to the first how ever many inputs (depending on how many switches they give you). It also only applies to the sync inputs (h/v). Running other types of signal that doesn't use those inputs (component, svideo) are unaffected.

[Carpetman]

Thanks for the great info! That does help out a lot. It's a shame it can't be turned off in older models, but at least now we know which ones to get for which kind of application. At least until someone figures out the best way to drop that voltage level to a safer range.

You're very welcome! Putting the 470 ohm resistor in the H/C or V output should still make it safe for non TTL devices

[jayde6]

You're very welcome! Putting the 470 ohm resistor in the H/C or V output should still make it safe for non TTL devices

I forgot that that was mentioned. Is there a preferred one of the two to add it to? Or does it not really matter?

[Carpetman]

You're very welcome! Putting the 470 ohm resistor in the H/C or V output should still make it safe for non TTL devices

I forgot that that was mentioned. Is there a preferred one of the two to add it to? Or does it not really matter?

You would put the resistor on the H/C output for RGBs, and both for RGBHV.

[Dochartaigh]

So I have an Extron Crosspoint Ultra 128 HVA matrix switcher, and there's little switches on the back. I'm assuming I want them set on 75 ohm? (instead of 510, and it says H Sync and V Sync below those switches).

510 is the default, the manual says you should switch them to 75 ohm if your sync signal is non-ttl greater than 5v p-p. It only applies to the first how ever many inputs (depending on how many switches they give you). It also only applies to the sync inputs (h/v). Running other types of signal that doesn't use those inputs (component, svideo) are unaffected.

Thank you for the reply, but I honestly don't understand any of what you said. I'm using regular video game consoles like RGBNES, SNES, Genesis, PS1, PS2, Xbox, etc. All are connected via RGBs SCART (except the Xbox which is component)...which setting would be best to use? - they're all going to Sony PVM/BVM's for the most part.

[jayde6]

Thank you for the reply, but I honestly don't understand any of what you said. I'm using regular video game consoles like RGBNES, SNES, Genesis, PS1, PS2, Xbox, etc. All are connected via RGBs SCART (except the Xbox which is component)...which setting would be best to use?

First I just want to say I'm still in the process of learning all this stuff myself so if you want to hold off for an expert, please do.

The switches are really only for conditioning the input as crosspoints output 75 ohm sync regardless of what you put into it.

The way I understand it is, your snes and genesis both output ttl sync so the switches should be set to 510 ohm, the manual says to only use the 75 ohm switch if the input isn't ttl and has voltage higher than 5v p-p. So those are fine. Iv'e read the RGBNES has a toggle on the board to switch from ttl to 75ohm. Both of those should be fine with the crosspoint at 510 ohm switch setting. The ps1 and ps2 are either going to use sync on luma or a sync stripper, depending on your scart cable. Again should be fine with the 510 ohm. The Xbox being plugged in via component cables doesn't even use the crosspoints sync circuitry so it doesn't matter the switch setting.

This is assuming ntsc consoles and typical scart cable types. Other region consoles and oddball cables may give a different sync output that would require you to flip the switch to 75 ohm.

Also this is all on the input side. Depending on what version crosspoint you have and what it's hooked up to, the output voltage may still be to high, but as Carpetman pointed out that can be fixed with a 470 ohm resistor.

Long answer I know, but I wanted to "show my math" in case I have something wrong and then someone who knows more can give us both the right answers.