CRT and VGA displays simultaneously on stock A1200?

[A1200Dude]

Help please!

I currently have a mostly-stock A1200 (accelerator card, no flicker fixer) hooked up to a NEC AccuSync LCD 71V monitor via the Commodore 23-pin to 15pin adapter...great display for retro systems, displays standard 15KHz Amiga modes in addition to 31KHz and several in between. Love it, but wanted to add a CRT alongside for gaming and a more "authentic" graphics experience.

I found a guy on Facebook marketplace that sold me an Amiga 1080 CRT in good condition and it is currently in transit. What I'm looking for now is a set-it-and-forget-it way to get both displays connected to the A1200 at the same time, without having to swap cables at the 23-pin Amiga RGB port all the time. A dual-monitor, duplicate-display setup, if you will.

I found both a VGA splitter and a 15-pin VGA to 9-pin RGB cable on Amazon that at initial glance looked like they would do the job...connect the splitter to the existing 23-to-15 adapter, plug the VGA monitor into one split, and the 15-to-9 cable into the other split to then send to the 1080. But after talking it through with another user on Facebook, he pointed out that it wouldn't work because the CSYNC line from the Amiga would not pass through to the CRT from any of the splitters and cables in the chain.

I guess what I'm looking for is...are there existing solutions that I am overlooking? Or is this purely a create-your-own-custom-cables thing? If the latter, are there any users here that create cables/splitters that can help with this, or can point me in the right direction? I have zero DIY skills when it comes to cabling so any help getting both monitors connected and displaying simultaneously would be TREMENDOUSLY appreciated!

[A1200Dude]

Sheesh, I hadn’t even thought about using composite but that would definitely be the simplest solution.  Is the quality decent enough for games compared to RGB or is there a considerable and noticeable drop off?

[A1200Dude]

Ok, I'll just go the composite route then. Now my next question(s)...will the composite output of the 1200 automatically "turn off" when a non-15KHz mode is displayed (e.g. my Workbench screen is Productivity mode)? Or will the 1080 show a scrambled screen?

Also, is there a way to have all 15HKz modes display solely on the 1080 and all the non-15KHz modes display solely via RGB/VGA? Would really like as seamless a "dual display" setup as possible.

[A1200Dude]

Ok, so the 1080 arrived and I hooked it up to the 1200 via composite. However, after some fiddling with the front controls of the monitor, I'm only able to display in B&W. Any ideas what could be wrong? (and yes, I've fiddled with the color knob)

[A1200Dude]

Yes, the 1200 is a PAL unit, but I thought the 1080 was capable of displaying both NTSC and PAL modes. If it were an NTSC television that I was connecting, I could understand that explanation, but not sure I understand why that would matter with a monitor that can otherwise show the mode.

I do have an RGB cable coming in the mail, so I'll be curious to see if that will display the color properly. But if it does, then I'm back to square one with this thread, and needing a way to switch between the monitors without having to constantly swap out the cable (and wearing down the connector on the 1200).

[A1200Dude]

Ok so it seems like the issue is indeed having a PAL Amiga connected via composite to an NTSC monitor, which as a result will only display the image in black and white. Before I completely give up on this and go the RGB route and swap cables constantly, would something like this work to bridge the PAL/NTSC issue:

THE CIMPLE CO - NTSC to PAL Converter Kit - TV Converter from PAL to NTSC - Bi-Directional TV System Converter Adapter with Two RCA Cables - (White) - Does NOT Convert Actual DVD OR VHS, ONLY Output https://www.amazon.com/dp/B07RHQKHWD/ref=cm_sw_r_cp_tai_GMHxDb3E6MZVF

Could this indeed convert the PAL composite signal coming out of the Amiga and turn it into a full-color NTSC composite signal that the Commodore 1080 monitor could properly display?

[A1200Dude]

There is a switch on the front of the 1080 for "comp." and "sep." and inputs on the back for "video" and "chroma." I've tried every combination amongst those four, and still no color composite signal shows, only B&W when on the "video" input ("chroma" displays nothing).

I'm intrigued by what you said here: "Another thing is that you can jumper the A1200 and make it default into NTSC mode."

Is this easy to do? Will this then display an NTSC color signal out of the composite port, or merely make the unit think it's NTSC but video would be unchanged?

If I can't get the composite to work properly, I am back at square one in terms of needing to split the RGB port. Can't believe this is proving to be as hard/rare as it is.

[A1200Dude]

I've had a couple of other thoughts that might be potential solutions...

A DB25 switch box like this to use with the Amiga RGB port (that way, each monitor gets its proper full RGB output):
https://www.amazon.com/CablesOnline-Parallel-Printer-Rotary-SB-001/dp/B00E6SQL46/ref=sr_1_8?keywords=db25+switch+box&qid=1566750732&s=gateway&sr=8-8

...assuming that the 23-pin cables for both displays would still fit in the DB25 connector, albeit without locking into place, and that all the proper wiring would passthrough correctly.

OR...a VGA-to-composite adapter:
https://www.amazon.com/dp/B002PXFJ2O/?coliid=I19T8GABAQG631&colid=2TGZ79CDNNMPT&psc=1&ref_=lv_ov_lig_dp_it

...which would come off of a VGA splitter connected to the 23-pin to 15-pin VGA adapter, and then go into the composite on the 1080.

I did order the 15-pin VGA to 9-pin RGB cable I referenced originally, figured if it doesn't work I'll just sent it back. But I'm thinking that the switch box idea would definitely be ideal, as both monitors would be hooked up via RGB then. Has anyone ever used a switch box like that to drive two Amiga displays? Or would this not be doable due to the Amiga's sensitivity to hot-swapping?

[A1200Dude]

Revisiting this...

So I think I will likely go the DB25 switch box route, but would something like this also do the trick?...

https://www.amazon.com/DB25-Female-Male-Cable/dp/B0743YH9TZ/   (This would be preferable as both monitors could then display simultaneously as needed, vs. one or the other with the switch box.)

With either method, I plan on slicing off two pins and part of the DB25 connectors so that the DB23 Amiga connectors fit. Does it matter which two pins (left or right side) get the axe?