Page 1 of 1

Mysterious device

Posted: Tue Mar 18, 2025 12:05 am
by robcfg
Hello, fine people!

I found a device that plugs into the monitor port, has an audio out jack (2.5mm instead of 3.5mm, so more like the remote jack) and contains an Astec modulator to output a RF signal.

I don't even know how to name it!

Does anyone know if this is a hobby kit or a commercial product? Or if it's mentioned on any magazine of the time?

Here are some pictures of the device:

Re: Mysterious device

Posted: Tue Mar 18, 2025 12:06 pm
by robcfg
The plot thickens! :mrgreen:

The pinout of the DIN 5 on the device seems to match the monitor port on the Dragon, but it needs voltage on pin 5 (usually unconnected) to feed a 7805 regulator that provides power to the modulator. Maybe it requires modding a Dragon 64 to get 12v in that pin for the regulator.

It seems that it's intended for a 64, because of the 12v needed to feed the modulator for the regulator, and a tiny label that reads "MO.DRAG64" :D

Re: Mysterious device

Posted: Tue Mar 18, 2025 2:32 pm
by sixxie
Weird. Reckon it's just a way to get TV out on a different channel?

Re: Mysterious device

Posted: Tue Mar 18, 2025 5:20 pm
by robcfg
Without audio?

Re: Mysterious device

Posted: Tue Mar 18, 2025 11:04 pm
by Alastair
Could it be a self-build to connect a Tano Dragon to a PAL TV?

Re: Mysterious device

Posted: Wed Mar 19, 2025 12:14 am
by robcfg
I don't think so unless you also modify the video signal generation to output PAL-compatible composite video, which is basically what regular Dragons do.

It probably is a very custom solution to someone's very specific problem, but there are details like the 2.5mm audio jack that I don't get... :D

As I mentioned earlier, I don't even know how to name the device so I can add it to our wiki.
Weird. Reckon it's just a way to get TV out on a different channel?
Definitely weird. How could we determine which channel is the modulator using? I'm not familiar with this model in particular and there's no model tag anywhere to be seen. It may have a label on the underside, but that's glued to the bottom.

Could it be a solution to a broken internal modulator? But then again, why not use the audio signal and have a separate jack for it? The Dragon is not exactly known for its sound generation capabilities, though I have to say that you can get some interesting sound with a program like Synther7.

Re: Mysterious device

Posted: Wed Mar 19, 2025 8:36 am
by sixxie
I do think some of those modulator models were video-only, so maybe this was all there was to hand, so the audio out is to manually hook that up separately?

Re: Mysterious device

Posted: Wed Mar 19, 2025 11:08 am
by robcfg
Maybe... :D

But not many TV's have an Audio Input jack, so probably that would got to speakers or headphones. Which again seems weird because of the 2.5mm jack. Of course the owner could have an adaptor.

Would "Composite Video to RF with split Audio converter" be an appropriate name for this contraption?