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NFG Forums => SIG X68000 => Topic started by: Segasonicfan on September 10, 2014, 08:22:05 AM

Title: The Definitive Dual Monitor Switching Circuit for X68000
Post by: Segasonicfan on September 10, 2014, 08:22:05 AM
EDIT: uploaded pics as requested, since photobucket killed all links.  I make much better looking stuff now, 12 years later, heh.  NFG forums forever!!

Here is a really useful little circuit I came up with.  It instantly switches the 31khz/15khz sync between outputs using the HD detect pin on the ISL59885.  Moreover, this IC corrects all sync pulses and standardizes them (my downscanner would not work without it!) 
The great benefit of this is that it can save your low-res CRT from damage and from the inconvenience of not knowing which mode your game is on boot.  Just plug in 2 monitors (a VGA and low res CRT) and watch it swap the signal between the two whenever the X68000 is outputting video.  Also works great on my Extron VSC500 using a KVM switch on my 36" low res CRT :)


-Segasonicfan
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: famiac on September 10, 2014, 11:24:30 AM
wow this is really useful! thanks! I won't be using it since i have an official monitor, but i might still build this just in case.

I can't get the link to work on how to obtain c-sync. Is there a mirror?
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: Segasonicfan on September 10, 2014, 04:05:37 PM
Thanks Famiac!  Link fixed :)
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: famiac on September 11, 2014, 10:32:06 AM
Hey segasonicfan, do you have any formal education in electrical engineering?
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: Segasonicfan on September 11, 2014, 12:38:58 PM
Quote from: famiac on September 11, 2014, 10:32:06 AM
Hey segasonicfan, do you have any formal education in electrical engineering?

heh, not really.  Took some online classes and read books.  But I have 10+ years of hands on work, some in the field repairing arcade equipment.  The formal education won't take you as far as doing it yourself.  I remember in college they just blabbled on about "how electrons move" trying to explain why transistors are PNP or NPN.  I rather know that I need a 2N3904 for a circuit I'm building :)

Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: famiac on September 11, 2014, 04:31:35 PM
Off-topic post, sorry. Continuing via PM
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: idrougge on December 09, 2025, 01:00:07 AM
@Segasonicfan I have some ISL59885 chips at home so I thought I would try to build your circuit, but your Photobucket pictures are no longer available. Do you have backups anywhere?
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: Segasonicfan on December 26, 2025, 10:52:08 AM
Quote from: idrougge on December 09, 2025, 01:00:07 AM@Segasonicfan I have some ISL59885 chips at home so I thought I would try to build your circuit, but your Photobucket pictures are no longer available. Do you have backups anywhere?

I do have backups!  I backed up everything from Photobucket and tend to have all that sort of stuff always saved :)
I'll dig up the old HDD and post here soon, probably after the holidays though

Long live NFG forums and retro gaming preservation !!
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: NFG on December 26, 2025, 11:55:17 AM
Quote from: Segasonicfan on December 26, 2025, 10:52:08 AMI'll dig up the old HDD and post here soon, probably after the holidays though

Please feel free to use the forum or the wiki to host your images.  I've got lots of space and bandwidth, and I'd be happy to be a reliable source for the images used here.
Title: Re: The Definitive Dual Monitor Switching Circuit for X68000
Post by: Segasonicfan on December 27, 2025, 12:27:44 PM
Quote from: NFG on December 26, 2025, 11:55:17 AM
Quote from: Segasonicfan on December 26, 2025, 10:52:08 AMI'll dig up the old HDD and post here soon, probably after the holidays though

Please feel free to use the forum or the wiki to host your images.  I've got lots of space and bandwidth, and I'd be happy to be a reliable source for the images used here.

Thank you!  You rock!
I updated the main post to include the schematic and images of the old ugly circuit from 2014 ;D