LCD only works with NTSC

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mrtinb
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LCD only works with NTSC

Post by mrtinb »

Hi

It's not easy to get the picture to show on a monitor after my Phillips CM11342 CRT died.

The best results I've had so far is sending the composite signal through ZX-CCB and to a 4.3" car LCD. The signal stopped jumping, when I removed the modulator from my board.

I can get a steady picture, when I connect the resistor for NTSC. Look at picture 1. (The characters are a little rough on the edged, as the monitor has very low resolution.)

However when I remove the resistor to have PAL, the picture is jumping, and the lowest lines are unreadable. (Picture 2)

I know the 4.3" monitor is not great, but it's the monitor I have, that gives the most steady picture, or giving a picture at all.

I was hoping to get my Lambda Colour Pack to work, but that will never work with the NTSC signal I'm generating at the moment.

The ULA I'm using is Andy's ULA.

Any ideas how to get a steady PAL signal?

Image

Image

P.S. I know that ZX81 does not send NTSC or PAL, but you get the idea.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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1024MAK
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Re: LCD only works with NTSC

Post by 1024MAK »

Unfortunately the circuitry in most LCD TVs almost always supports 525 line, 60Hz NTSC. Some have good support for 625 line, 50Hz (PAL). But not all. It’s not helped by the non-broadcast video signal that the Sinclair computers produce :(

Some of the cheap small LCDs for vehicle use are known to be especially bad at coping with the output from Sinclair computers.

I assume you have:
  • Disconnected the video input to the modulator,
  • Tried adjusting the preset controls on the ZX8-CCP.
I suggest you try another LCD TV. See if there are any charity shops, pre-owned / second hand shops or similar that have a 15” or smaller 4:3 aspect TV going for a low price. Not many people want these, so they are often sold at bargain prices.

Mark
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mrtinb
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Re: LCD only works with NTSC

Post by mrtinb »

Yes I have disconnected the modulator, and adjusted the ZX8-CCB quite a bit.

Now I have ordered an old 10" B/W CCTV CRT monitor, and is looking forward to figure out how to send video to it's proprietary RJ11 connector, which is the only input to this monitor.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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mrtinb
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Re: LCD only works with NTSC

Post by mrtinb »

Today I received a security monitor for cctv cameras. It’s analog but has RJ12 plugs for the cameras.

I cut over the cable and found some help with Google, and it now connects to my ZX81 with dupont wires.

What a great picture. Yes!

Unfortunately it has a humming sound like grasshoppers. But in fast mode, and in some games it is silent.

I hope it’s just the very very long cables meant for the camera. I hope a shorter version will do the trick.
Martin
https://zx.rtin.be
ZX81, Lambda 8300, Commodore 64, Mac G4 Cube
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