Print Page - CTM640 - dim display with non-CPC source

Title: CTM640 - dim display with non-CPC source
Post by: gw0udm on 10:54, 28 July 21

Hi

I'm experimenting with using other sources than a CPC with an Amstrad CTM640 monitor.

I'm trying a Spectrum Next at the moment, which fortuitously does seem to work with the 5V output that the monitor provides.

I've made up an adaptor cable which take the RGB and sync from the Next to the pins on the monitor input. It works, but the display does seem quite dim compared to the CPC.

I haven't connected anything to the luminance pin - would this make any difference?

James

Title: Re: CTM640 - dim display with non-CPC source
Post by: Bryce on 11:43, 28 July 21

Nope, Luminance is only for the monochrome picture. Your problem is that the RGB levels are lower than the CPC's RGB signals.

Bryce.

Title: Re: CTM640 - dim display with non-CPC source
Post by: gw0udm on 13:34, 28 July 21

Thanks

Ah well never mind. It is actually quite usable, there may be some way of adjusting the signals coming out of the Next.

I've got a few other monitors here as well to try it with.

James

Title: Re: CTM640 - dim display with non-CPC source
Post by: eto on 17:52, 28 July 21

Quote from: gw0udm on 10:54, 28 July 21It works, but the display does seem quite dim compared to the CPC.

Probably you already did that but since it wasn't mentioned: did you adjust the brightness?

Title: Re: CTM640 - dim display with non-CPC source
Post by: gw0udm on 22:51, 28 July 21

Well you know what I thought I had... but just tried it again and actually it really helped! So obviously I hadn't... so thanks very much for the tip, it is much better now. I still think it's not quite as bright as the CPC but it's much more usable.

I've got a couple of these monitors now and it's really handy have the 5V output on the front.

James

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General Category => Technical support - Hardware related => Topic started by: gw0udm on 10:54, 28 July 21