Ossc or XPC-4 use on BVM

[toyhopperhk]

Hello guys
I want X68000XVI use on Sony Crt Bvm -D24,
have two choice now, Ossc or XPC-4?
Thx

[hyrulebr]

Hi

I have a D20 and have this obssession: Fully use my X68000 with this monitor!   

Well, you can use the X68000 with just a "sync combiner" (e.g. any extron RGB interface) at 15khz directly without the need of a OSCC or XPC-4. Nice picture with bold scanlines.

But at 31khz the image is dark, greenish.

I tried to use more than 7 different models of Extron interfaces (580xi, 160xi, 130xi, 203rxi, 190, etc) and the Kenzei sync combiner (https://www.beharbros.com/kenzei).

What worked:

A XPC-4 (using the device vga out at 480p). I don't know how much lag are involved but is very strange to use a digital equipment like that in a CRT monitor!   
An Extron Emotia downscaling the 480p image to 240p. I liked it but needs to test with more games.

To test in future:

TV one corio2 (I bought one using the tips in this thread:  https://shmups.system11.org/viewtopic.php?f=6&t=63226). I'm hoping to get a Emotia performance in a smaller and newer device.

About the OSCC I can't say too much because I never used one, but How you plan to send the signal to a BVM? HDMI to SDI or HDMI to VGA (using these cheap converters)?

[frankmonk]

you can go this route:
xvi>ossc vga in> hdfury or any other cheap DAC>sync combiner>sony bvm
just too much cabling imo.
I also tried the 203rxi route but kept having weird ouput in 31khz mode.
never tried with my emotia but the fact that it only accepts 31khz input just doesn`t sound right to me. not sure how many games are booting in 15khz mode only.

[LowDefAl]

Well, you can use the X68000 with just a "sync combiner" (e.g. any extron RGB interface) at 15khz directly without the need of a OSCC or XPC-4.

You can literally tie the syncs together with a solder bridge and it will work fine on a "standard" 15khz BVM model*. No device should be needed in any form. Not ideal practice perhaps but it certainly works. Don't complicate the setup unless it's really necessary. I haven't tried that at 31khz, but if you are using a X68000 scart cable and a scart to BNC adapter for a 31khz compatible BVM, it shouldn't make a difference. 

*Not suggested for consumer displays due to signal voltages

[leonk]

X68k needs to be treated like a real PC.

It uses RGBHV with RGB being 0.7Vpp but HV sync is TTL 5Vpp!!  Just because you can make a scart cable for it doesn’t make it ideal. Use the VGA port as VGA and try to handle that. Most common modern usage is OSSC to LCD PC monitor.

[DMR]

The video board of the x68000 XVI at least, that can be removed, is this board responsible for converting the video signals?

Would it be possible to come up with a device that replaces this board that outputs HDMI instead?

[hyrulebr]

Well, you can use the X68000 with just a "sync combiner" (e.g. any extron RGB interface) at 15khz directly without the need of a OSCC or XPC-4.

You can literally tie the syncs together with a solder bridge and it will work fine on a "standard" 15khz BVM model*. No device should be needed in any form. Not ideal practice perhaps but it certainly works. Don't complicate the setup unless it's really necessary. I haven't tried that at 31khz, but if you are using a X68000 scart cable and a scart to BNC adapter for a 31khz compatible BVM, it shouldn't make a difference. 

*Not suggested for consumer displays due to signal voltages

I read somewhere that just mixing H + V isn't a good idea. But I don't know why. 

Well, at 31khz the timing and frequency of X68000 signal isn't under BVM/PVM tolerance/work range. As I told, BVM D series have the dark picture and using with a BVM A series the monitor recognize the singal as 1080i and with a wooble (shaking) screen. Probably at 15hkz all PVM/BVM are compatible and that's a good thing. 

[leonk]

OP.. have you gotten a chance to try the TV one corio2? 

I'm looking for a solution to connect to my 240p/480i capable PVM (doesn't support 31k).  I was wondering if there's any box out there that will accept X68000 31k/15k and always output 240p?

[TD-Linux]

You can modify an Extron sync combiner to work with the TTL open collector sync outputs of the x68000, which avoids the dim screen issue:

https://nfggames.com/forum2/index.php?topic=6559.0

[hyrulebr]

OP.. have you gotten a chance to try the TV one corio2? 

I'm looking for a solution to connect to my 240p/480i capable PVM (doesn't support 31k).  I was wondering if there's any box out there that will accept X68000 31k/15k and always output 240p?

Someday I will try the tv one corio2 with my X68000! So many things to do and just a small time avaliable every week. 

Regarding PVM/BVM I saw this auction last month in YAJ:

https://page.auctions.yahoo.co.jp/jp/auction/q287178972

And I asked the seller how he manage to get the Castlevania to working in a PVM 20L5. Castlevania only works with 31khz and I tested in the past a 14L5 with my X68000 and got the same greenish screen, dark screen as BVM D20.

He kindly replied to me this circuit he uses to combine sync:

Monitor: SONY PVM-D20L5J ・ Cable: self made HSync + VSync â†' CSync (5V + 74AC86 + 170Ω)
https://blog-imgs-127.fc2.com/s/u/z/suzume9/74ac86.png

Taking a better looking now in the YAJ listing, picture with start screen seems a little green in the japanese text, but maybe it´just the camera/angle/reflection because the next picture (cave stage) have the colors ok to me.

I don´t have the knowledge to build this circuit to test but I plan to ask someone to do it for me in the future. If someone wants to give a try first, please let me know the results.