Lambda colour kit

pemilsson
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Lambda colour kit

Post by pemilsson » Sun Oct 06, 2013 4:29 pm

Hi,
Yesterday I looked through a box of some old ZX80/ZX81 stuff and found a yellowish box that I now have found to be a Lambda colour kit.
Unfortunately it seems like the video input cable is missing, does anyone know where it needs to be connected on the PCB?
Is this something that I can use with my ZX80 or ZX81?
Does anyone have a manual for this unit?

Best regards
Patrik
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IMG_0424.jpg
Lambda colour kit
IMG_0424.jpg (49.86 KiB) Viewed 833 times
IMG_0423.jpg
Lambda colour kit inside
IMG_0423.jpg (77.56 KiB) Viewed 833 times

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PokeMon
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Re: Lambda colour kit

Post by PokeMon » Sun Oct 06, 2013 5:49 pm

I would think that there is no connection to the pcb necessary.
Looks like it is some logic to build up a colored signal instead of the monochrome with separate (color) modulator and (possibly) direct composite video out.
So I would say it just has to be connected via the expansion bus but I don't know, how you can define at least some default colors.

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siggi
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Re: Lambda colour kit

Post by siggi » Sun Oct 06, 2013 6:37 pm

Some information about the color module can be found in the German ZX-Team magazine 6/1992 (at page 19) in Tom's forum:
http://forum.tlienhard.com/magazin/1992/magazin_692.pdf

See also page 13 of 1/1996
http://forum.tlienhard.com/magazin/1994/magazin_194.pdf

The schema can be found at page 14 of 2/1994
http://forum.tlienhard.com/magazin/1994/magazin_294.pdf

The modules offers additional color ram starting at address 8192. Poke this and the following addresses to set the color.

HTH Siggi
My ZX81 web-server: online since 2007
http://zx81-siggi.endoftheinternet.org/index.html

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siggi
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Re: Lambda colour kit

Post by siggi » Sun Oct 06, 2013 6:56 pm

And here a picture of my color module: the cable is connected to the monitor output of the Lamda, and a color monitor or color tv set can be connected the the module's outputs:
P1070067_1024x768.JPG
P1070067_1024x768.JPG (217.23 KiB) Viewed 844 times
And here the rear side of the board:
P1070069_1024x768.JPG
P1070069_1024x768.JPG (238.15 KiB) Viewed 843 times
HTH Siggi
My ZX81 web-server: online since 2007
http://zx81-siggi.endoftheinternet.org/index.html

pemilsson
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Joined: Sun Oct 06, 2013 4:05 pm

Re: Lambda colour kit

Post by pemilsson » Mon Oct 07, 2013 3:55 am

Thanks for the info.
I will add the wire as it seems to be crucial.
I'm slowly translating the german magazine to try to get a better understanding.

Have I understood it correct that it says that I need to lower the supply for the ZX80/81 to 8V to limit the risk of overheating the regulator?
One connector on the box says Video the other TV, does it indicate that Video will give composite video out?

Should I expect a picture on the TV just by connecting everything or do I first need to set some of the parameters?

The wire with a connector is that expecting a composite video signal or the std video signal from the ZX80/81?

Right now I only have a modern TV that only can handle composite video. I hoped that this unit could help with that.

Best Regards
Patrik

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siggi
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Re: Lambda colour kit

Post by siggi » Mon Oct 07, 2013 3:28 pm

pemilsson wrote:Thanks for the info.
I will add the wire as it seems to be crucial.
Yes, because that is the B/W video signal, which is "expanded" with colour information.
One connector on the box says Video the other TV, does it indicate that Video will give composite video out?
Yes
Should I expect a picture on the TV just by connecting everything or do I first need to set some of the parameters?
Without setting any color information you should be able so see something ...
The wire with a connector is that expecting a composite video signal or the std video signal from the ZX80/81?
It expects a composite video signal. The Lamda has such an output, but not a "standard" ZX81.
My ZX81 web-server: online since 2007
http://zx81-siggi.endoftheinternet.org/index.html

pemilsson
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Re: Lambda colour kit

Post by pemilsson » Mon Oct 07, 2013 7:08 pm

Thanks again!

Now I know how to progress.
I will start with making this composite video modification on my ZX81 to first have that one working with the TV. Do you know if this box needs the back porch in the video signal? More importantly will it have it in the output? If no and yes, I probably would be able to use this for my ZX80 too. I will do some tests tonight.

Best regards
Patrik

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1024MAK
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Re: Lambda colour kit

Post by 1024MAK » Tue Oct 08, 2013 12:03 am

Looking at the circuit schematic, it looks like the colour board just adds colour information to the existing video signal.
I would expect better results if the ULA in the ZX81 generates a back porch.
A ZX80 will not generate a back porch, so a TV may not correctly show a colour picture.

Mark

pemilsson
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Re: Lambda colour kit

Post by pemilsson » Tue Oct 08, 2013 4:16 am

Tried one of the easy video mod mentioned in another thread but without luck, my ZX81 has the ULA that makes a back porch but my issue might be that it's a PAL version and I'm now in NTSC land. The reason I even tryed was that I have a Wii (PAL) that works with this TV.

Should I drop this until I get a grip of a PAL TV?

Thanks
Patrik

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sirmorris
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Re: Lambda colour kit

Post by sirmorris » Tue Oct 08, 2013 9:42 am

The unit can be switched to NTSC using a jumper on the board. I can't tell you what it is off the top of my head but I'm sure someone will be along any second to fill in the details 8-)
--=== ZXpand+ ... A more moderner all-in-one upgrade solution for ZX81 ===--
* SD/MMC storage * 32K Hires-capable RAM * AY sound chip * Joystick port * Serial *
* BASIC enhancements - plug & play * Reset button * Auto-boot facility *

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