Original analog video without I/O board? Possible!

[paulbnl]

I don't see any problems having 2V on TV sync. No one design TV where 2V instead of 1V external signal will damage it. Also TV MUST have 75 Ohm pull down resistor which together with internal I/O board 100 Ohm resistor will give just a little more than 1V.

Yes with I/O board the 3.3V is lowered to about 1V by the 100 Ohm resistor which is at the limit of SCART.

I believe the stated 2V is with 75 Ohm pull down already so the adapter is outputting around 5V with USB power plugged in.

I doubt devices have tolerance for double voltage. Better be safe than sorry.

[pacoarcade]

Indeed. Any VGA->SCART cable should have a resistor on the sync line. 2V may work for a while but it will damage something in the long run.

I don't see any problems having 2V on TV sync. No one design TV where 2V instead of 1V external signal will damage it. Also TV MUST have 75 Ohm pull down resistor which together with internal I/O board 100 Ohm resistor will give just a little more than 1V.

I have measured 2V on the pin 20 of the SCART connector. According to this information maximum Vpp should be 1V.

Devices like OSSC are pretty sensible to higher voltages for CSYNC... I prefer to stick to the sweet spot of ~400mV. This value works fine for all TVs I've tried.

[solo20]

will hdim to Component Video Cable with Audio Work on direct video like this one will i get sound ?

https://www.amazon.com/Insten-Compatibl ... 1583444920

[Sorgelig]

will hdim to Component Video Cable with Audio Work on direct video like this one will i get sound ?

https://www.amazon.com/Insten-Compatibl ... 1583444920

No. It's not HDMI cable.

[Ingy]

I have Direct Video working with the UGREEN adapter already, but I was still getting quite a bit of audio buzzing (at normal volumes) with my TV, so I picked up a Tripp-Lite P131-06N adapter cheaply since someone earlier in the thread mentioned it having less audio noise than even the UGREEN one. When I first tried it I just got a jagged, rolling pattern on my TV, so after a bit of fruitless MiSTer.ini tinkering I just assumed that my adapter had a different, incompatible chipset or that using RGB SCART instead of a BNC cable like the other user had was making the difference.

I went back to using the UGREEN adapter, but last night I tried blindly loading a core with the Tripp-Lite one out of curiosity, and it displayed perfectly! I didn't test every core, but at least NES, SNES, GBA, SMS, Mega Drive, PC Engine, Neo Geo and Commodore 64 (switching between NTSC and PAL) were working fine. I notice that another user earlier in the thread had a similar issue with the Menu core giving a rolling picture while other cores were displaying correctly, but I'm using a consumer TV from the mid-80s rather than a broadcast monitor as they were.

After that try these to see if anything changes:

Code: Select all

[Menu]
video_mode=640,30,60,70,240,4,4,14,12587
vga_scaler=1
direct_video=0

Following the advice they received, this morning I've been trying out different video_mode lines for the menu with the scaler enabled adapting the above example, but I'll presumably need something different for a consumer TV. I've tried various "240p" video_mode lines I've found in different threads without too much luck. The closest so far was this, which seems stable horizontally but rolls vertically, and also seems a bit squished (due to the pixel clock?):

Code: Select all

video_mode=320,8,32,24,240,4,3,16,6048

Any guidance would be appreciated!

[Ingy]

I've solved my audio buzzing issues through another avenue, by running the audio output of the UGREEN adapter through a cheap 6J1 tube preamplifier before it connects to the audio input of my RGB SCART cable. It's essentially noiseless up to high volumes now. The line output level of both of the HDMI to VGA adapters I tried seems unusually low, before adding the preamplifier I had to turn the TV volume up more for the MiSTer than for any of the consoles I have connected to the TV.

Anyway, I'm not too bothered about getting the Tripp-Lite adapter working with the Menu core now. Hope this information helps someone else!

[witchmaster]

I bought a QGeeM HDMI to VGA adapter on Aliexpress: https://www.aliexpress.com/item/32864796089.html, that one also has an unsupported adapter chip, ones with AG6200 are quite hard to find. Five out of six adapters I have bought have an unsupported chip. The UGreen one I bought have a supported chip though. Any reliable source currently with supported AG6200 chips?

[MrXCuci]

with AG6200 are quite hard to find. Five out of six adapters

Bought this one, works fine. Needs to be powered though: Wholesale Product Snapshot Product name is Vention HDMI to VGA adapter Digital to Analog Video Audio Converter Cable 1080p for Xbox 360 PS3 PS4 PC Laptop TV Box Projector
https://a.aliexpress.com/_BTtEPP

[BonzoBits]

Bought this one, works fine. Needs to be powered though: Wholesale Product Snapshot Product name is Vention HDMI to VGA adapter Digital to Analog Video Audio Converter Cable 1080p for Xbox 360 PS3 PS4 PC Laptop TV Box Projector
https://a.aliexpress.com/_BTtEPP

That link is no longer available. I found a product with the matching description though - thanks for including this in your post.

[carrboroman]

I noticed a behavior on both PVM and 1084s, while using direct video and the hdmi-vga dongle, basically when changing core or resetting, the monitor gets out of sync, with waves, lines and high pitch noises coming from the monitor, until the new core/menu is displayed.

looks to me some signal (31Khz? can't measure) is generated between the cores loading .... is that a confirmed behavior on well-known dongles?

using the I/O VGA port nothing like that happens (it looses sync correctly only when rebooting, not when changing cores, and without hissing or showing colored stuff)


my concern is the monitor may suffer on long term

[solo20]

i have a consumer crt tv its ruff when it switch cores is losing the signal then finds it maybe in my case its the sog mod i did was crap work i do not get the high pitch noises like you do. its just very annoying for it to do that is there anybody selling a well done cable with this mod done by a pro?

[Sigismond0]

I've got a CRT and PVM that both go haywire during core changes with an IO board. I don't think this is specific to Direct Video, but rather MiSTer as a whole. Either there's an out of range signal going out during core changes, or no signal whatsoever, which would also explain the drop.

[carrboroman]

I've got a CRT and PVM that both go haywire during core changes with an IO board. I don't think this is specific to Direct Video, but rather MiSTer as a whole. Either there's an out of range signal going out during core changes, or no signal whatsoever, which would also explain the drop.

From what I can see, these are two different behaviors showing similarities (please try the directvideo with dongle and I'm sure you'll see the difference)

Using the I/O VGA there is no high pitch hissing, only loss of sync, while with the dongle and direct video you can hear the high pitch noise and see the monitor is not just losing sync, but trying to hook on something out of specs... if confirmed, my concern is that it may be damaging the monitor on long run.

@Sorgelig, could be there any out-of-specs signal coming from the dongle/HDMI port when a core is not providing the correct 15Khz signal? (like the linux base system taking briefly over again when changing core/resetting?)

here is my dongle chip btw, as far as I can tell is the same AG6200 as the reference ones:

[Sorgelig]

When core is loading, the HDMI chip is effectively disconnected and no one can control it. What signal is produced by VGA converter - i have no idea.

if confirmed, my concern is that it may be damaging the monitor on long run.

don't run it long in this condition.
But i suggest to get rid of monitor which can damage itself.

[carrboroman]

When core is loading, the HDMI chip is effectively disconnected and no one can control it. What signal is produced by VGA converter - i have no idea.

So from what I read, you are saying your idea of using the whole directvideo and the AG62000 converter (as simply I did, following this very thread) is a solution you don't fully understand, and will damage CRT monitors?

don't run it long in this condition.
But i suggest to get rid of monitor which can damage itself.

You seem confused about this (...), let me clarify: the monitors (PVM 20M2U and Commodore 1084s) do not "damage themselves",it's your suggestion to use directvideo + HDMI converter that allows damaging frequencies to be fed to the monitors, and this is a problem for anyone using 15Khz CRTs.

..let me ask you Sorgelig, do you hate CRTs so much? Why don't you just officially stop supporting them (no more analog I/O boards anyway right?), instead of silly dismissing feedback when turns out you are frying them?

[Peredonov]

You seem confused about this (...), let me clarify: the monitors (PVM 20M2U and Commodore 1084s) do not "damage themselves",it's your suggestion to use directvideo + HDMI converter that allows damaging frequencies to be fed to the monitors, and this is a problem for anyone using 15Khz CRTs.

This is misguided, and not helpful in getting Sorgelig to care more about CRT support.

He's been pretty clear that the MiSTer is meant for HDMI/modern displays, and the analogue output is basically a bonus. It's nice that he actually supports it, even while "hating" CRTs. But the recommended HDMI to VGA solution is not necessarily going to damage your monitor. It's basically up to whatever your HDMI-VGA adapter does, which is what he means in that last post. Not all adapters do what yours does during core switching, so a different HDMI-VGA adapter will not cause the same issue even on more delicate monitors that can "damage themselves" ( gotta say that line made me ).

So your solution is easy: try a different adapter. They're cheap, it's not a big burden to cycle through a few until you find a good one.

[carrboroman]

You seem confused about this (...), let me clarify: the monitors (PVM 20M2U and Commodore 1084s) do not "damage themselves",it's your suggestion to use directvideo + HDMI converter that allows damaging frequencies to be fed to the monitors, and this is a problem for anyone using 15Khz CRTs.

This is misguided, and not helpful in getting Sorgelig to care more about CRT support.

He's been pretty clear that the MiSTer is meant for HDMI/modern displays, and the analogue output is basically a bonus. It's nice that he actually supports it, even while "hating" CRTs. But the recommended HDMI to VGA solution is not necessarily going to damage your monitor. It's basically up to whatever your HDMI-VGA adapter does, which is what he means in that last post. Not all adapters do what yours does during core switching, so a different HDMI-VGA adapter will not cause the same issue even on more delicate monitors that can "damage themselves" ( gotta say that line made me ).

So your solution is easy: try a different adapter. They're cheap, it's not a big burden to cycle through a few until you find a good one.

Ok... just curious, how can you dismiss it's "my" adapter and not the behavior of using dongles in general? Have you tried all the dongles either?
Please share which one certainly doesn't throw out-of-specs frequencies, that would help narrowing down and make the solution safe.

From what I understand though, nobody, even Sorgelig, by his own words, knows how this actually works so far (even if I admit I find strange a *passive* device will generate anything when "unplugged" )

I'm doing my part, I've been providing feedback on something potentially dangerous for CRTs monitor, and I apologize for my reaction to Sorgelig's dismissal, but given what the impact may be, I expected people here to take the info I provided a bit more "seriously".

I'll try to dig more info as much as I can, but as a community, I don't think shrugging or tell "change dongle and hope" is the right answer.

[dshadoff]

A second approach - since the act of changing cores creates a situation where the FPGA is not controlling the HDMI output, and that leads the combination of dongle + monitor to misbehave, it seems to me that an alternate solution would be to turn off the MiSTer when switching cores.

Do you have the same behavior when driving the monitor via the I/O Board's VGA output ?

[carrboroman]

A second approach - since the act of changing cores creates a situation where the FPGA is not controlling the HDMI output, and that leads the combination of dongle + monitor to misbehave, it seems to me that an alternate solution would be to turn off the MiSTer when switching cores.

Do you have the same behavior when driving the monitor via the I/O Board's VGA output ?

The I/O Board VGA output doesn't make the monitor hissing, no, it just loses sync.
Anyway, the hissing with the dongle happens when booting too, will check to confirm 101%.

Just to understand, can someone confirm the I/O board DAC is "constantly" hooked like the dongle would be, or is it engaged differently?

To recap, looks like the DE-10 HDMI itself is sending high-res signal while the cores are reloaded or any situation when Mister is not in control (reboot etc..)
In such case it wouldn't matter the dongle, and basically it is impossible to get rid of, rendering the whole solution not viable.

That would leave as the only safe option the I/O board VGA DAC, engaged only through Mister, therefore always either providing only the correct (configured) signal or no-signal, confirming the behavior seen.

[SmokeMonster]

[removed]

[LewisD]

don't run it long in this condition.
But i suggest to get rid of monitor which can damage itself.

I strongly vote to remove direct video support if there is even a minute chance that it can physically damages monitors. I'm extremely upset to hear that this is a risk, because I've been recommending these dongles to people. The implications for the legitimacy of the entire MiSTer project would come into question if it remains.

Respectfully, you are already jumping to unnecessary conclusions. You have a single person with anecdotal evidence that a miscellaneous dongle is causing issues. Why not wait for some testing of the available dongles on the market before creating premature drama?

[MottZilla]

When core is loading, the HDMI chip is effectively disconnected and no one can control it. What signal is produced by VGA converter - i have no idea.

if confirmed, my concern is that it may be damaging the monitor on long run.

don't run it long in this condition.
But i suggest to get rid of monitor which can damage itself.

Or before changing cores they could change the video input on the monitor or turn it off while the cores change. If you're that paranoid about it.

[SmokeMonster]

[removed]

[Sorgelig]

I strongly vote to remove direct video support if there is even a minute chance that it can physically damages monitors. I'm extremely upset to hear that this is a risk, because I've been recommending these dongles to people. The implications for the legitimacy of the entire MiSTer project would come into question if it remains.

Stop to be silly, ok? There is no way normally working monitor can suicide.

[SmokeMonster]

Sorry, I may have been misreading your post earlier.