Sidequest: VGA scan doubler

General discussions or ideas about hardware.
User avatar
Smonson
Trusted Guru
Trusted Guru
Posts: 605
Joined: Sat Oct 28, 2017 10:21 am
Location: Canberra, Australia
Contact:

Re: Sidequest: VGA scan doubler

Post by Smonson » Thu Dec 31, 2020 2:47 pm

exxos wrote:
Thu Dec 31, 2020 2:39 pm
If you look at the first image I posted the colours show how its wired..
Aha, right, I see what you mean. Sync looks good in your photos. It's only blank that needs to be disconnected. If you can't disconnect blank on the H5 then it will probably at least work for monochrome.

User avatar
exxos
Site Admin
Site Admin
Posts: 13816
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: Sidequest: VGA scan doubler

Post by exxos » Thu Dec 31, 2020 3:04 pm

Smonson wrote:
Thu Dec 31, 2020 2:47 pm
Aha, right, I see what you mean. Sync looks good in your photos. It's only blank that needs to be disconnected. If you can't disconnect blank on the H5 then it will probably at least work for monochrome.
I tried disconnecting the blanking to the DAC IC, makes no odds.. if I remove the buffer blanking it just goes like this...

IMG_5922.JPG
IMG_5922.JPG (195.1 KiB) Viewed 359 times
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?

User avatar
exxos
Site Admin
Site Admin
Posts: 13816
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: Sidequest: VGA scan doubler

Post by exxos » Thu Dec 31, 2020 3:06 pm

If I feed the VGA board blanking direct to the DAC it does this...

IMG_5923.JPG
IMG_5923.JPG (245.66 KiB) Viewed 358 times
IMG_5924.JPG
IMG_5924.JPG (463.27 KiB) Viewed 351 times
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?

User avatar
exxos
Site Admin
Site Admin
Posts: 13816
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: Sidequest: VGA scan doubler

Post by exxos » Thu Dec 31, 2020 3:42 pm

Oh this is odd...

Like there is a missing pullup or something...





EDIT:
Even more odd, I just split the cables a tiny bit and the problem has gone away.. I think it needs a pull up on Hsync somewhere..

EDIT2:

Its hard to work out, but I think they all need a pullup other than Vsync maybe..
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?

User avatar
exxos
Site Admin
Site Admin
Posts: 13816
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: Sidequest: VGA scan doubler

Post by exxos » Thu Dec 31, 2020 4:49 pm

BOGDE WIRES :excited: :excited: :excited:

IMG_5930.JPG
IMG_5930.JPG (354.31 KiB) Viewed 333 times
IMG_5931.JPG
IMG_5931.JPG (276.02 KiB) Viewed 333 times
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?

User avatar
Smonson
Trusted Guru
Trusted Guru
Posts: 605
Joined: Sat Oct 28, 2017 10:21 am
Location: Canberra, Australia
Contact:

Re: Sidequest: VGA scan doubler

Post by Smonson » Thu Dec 31, 2020 10:54 pm

Awesome! I wonder why it needed that? The logic signals are buffered so they're supposed to be driven with a decent amount of current. Still, I'm glad you were able to sort it. Looks good now!

User avatar
exxos
Site Admin
Site Admin
Posts: 13816
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
YouTube: https://www.youtube.com/user/exxosuk
Contact:

Re: Sidequest: VGA scan doubler

Post by exxos » Thu Dec 31, 2020 10:58 pm

Smonson wrote:
Thu Dec 31, 2020 10:54 pm
Awesome! I wonder why it needed that? The logic signals are buffered so they're supposed to be driven with a decent amount of current. Still, I'm glad you were able to sort it. Looks good now!
I suspect the GLUE doesn't drive them high, so buffering wouldn't help.

I might try closure tomorrow ;)

Great board anyway! Just sorry its taken so long to get some time to actually test the thing!
https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?

User avatar
Smonson
Trusted Guru
Trusted Guru
Posts: 605
Joined: Sat Oct 28, 2017 10:21 am
Location: Canberra, Australia
Contact:

Re: Sidequest: VGA scan doubler

Post by Smonson » Thu Dec 31, 2020 11:06 pm

I may need to revisit how they're buffered I guess! Thanks exxos!

Post Reply

Return to “HARDWARE DISCUSSIONS”