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General Category => Amstrad CPC hardware => Topic started by: retro space on 20:06, 10 June 24

Title: Green Monitor GT65 black level
Post by: retro space on 20:06, 10 June 24
I got a Green Monitor GT65 last weekend, and I was wondering if it is possible to tweak the black level. It seems you can't make the background black without reducing the overal brightness seriously. Is there a fix for this?
Title: Re: Green Monitor GT65 black level
Post by: Gryzor on 07:54, 11 June 24
It's aaaall green, all the way down. Even when turned off, it's still green :D
Title: Re: Green Monitor GT65 black level
Post by: Benedikt on 18:19, 12 June 24
Quote from: retro space on 20:06, 10 June 24I got a Green Monitor GT65 last weekend, and I was wondering if it is possible to tweak the black level. It seems you can't make the background black without reducing the overal brightness seriously. Is there a fix for this?
I see no obvious way. You have to turn the brightness all the way down and the contrast all the way up.

Other than that, you could play with the resistors surrounding the contrast potentiometer, provided that you know how to work with CRTs.

Alternatively, you could try to build an external amplifier, perhaps with a diode to lower the black level of the amplifier output.
Title: Re: Green Monitor GT65 black level
Post by: ZorrO on 20:11, 12 June 24
There are these little yellow knobs inside the monitor, and one of them increases the contrast more than the outside one.
Just be careful because you have to play with it when it is turned on and open.
Title: Re: Green Monitor GT65 black level
Post by: dodogildo on 21:52, 12 June 24
You better don't open the case. not worth the risk.
Title: Re: Green Monitor GT65 black level
Post by: SerErris on 15:21, 14 June 24
I am sure you changed the background color from blue to black (and the border color), right? 
Just asking because I wondered as well and after setting it to black (and white font color) it was much better...
Title: Re: Green Monitor GT65 black level
Post by: abalore on 16:04, 14 June 24
You can do this: Get a CPC to RGB scart cable, then change it to connect the LUM (pin 6) to GREEN on the SCART, and leave blue and red unconnected. I tried this and you get the true 16 level green screen and a good, deep black.

Also you can try other combinations to get other monochrome screens with red, yellow, etc...

(of course this is with a scart color TV)
Title: Re: Green Monitor GT65 black level
Post by: McArti0 on 18:44, 14 June 24
Quote from: abalore on 16:04, 14 June 24you get the true 16 level green screen and a good, deep black.
27 levels !   8) .  
Title: Re: Green Monitor GT65 black level
Post by: abalore on 19:35, 14 June 24
Quote from: McArti0 on 18:44, 14 June 24
Quote from: abalore on 16:04, 14 June 24you get the true 16 level green screen and a good, deep black.
27 levels !  8) . 
Well, 16 simultaneous
Title: Re: Green Monitor GT65 black level
Post by: retro space on 05:47, 15 June 24
Quote from: SerErris on 15:21, 14 June 24I am sure you changed the background color from blue to black (and the border color), right?
Just asking because I wondered as well and after setting it to black (and white font color) it was much better...

Yes, I tried playing some games that have black background.
Title: Re: Green Monitor GT65 black level
Post by: VincentGR on 21:51, 16 June 24
Is there a deep black on Amstrad monitors?
Even when they're off, they are light gray  ;D
Title: Re: Green Monitor GT65 black level
Post by: Bryce on 08:03, 17 June 24
Quote from: VincentGR on 21:51, 16 June 24Is there a deep black on Amstrad monitors?
Even when they're off, they are light gray  ;D

I'm holding out until Amstrad release the CPC OLED edition. :)

Bryce.
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