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Old 25 May 2014, 03:55   #1
vimfuego
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Question Amiga 1000 composite video output (colour?)

Hi All,

I recently got a few A1000's, just going over them and some have colour on the single RCA composite output whilst others are only B/W.
I didn't think any of the early Amiga's had colour output unless you had an A520 plugged in and used its output.
So I guess my questions are, did the A1000 have colour output on the RCA video output and I just have a few faulty ones (B/W)? Or might have someone modified them for colour output on the RCA connector?

TIA
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Old 25 May 2014, 04:05   #2
T_hairy_bootson
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All the ones I have/had do colour composite.
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Old 25 May 2014, 06:45   #3
ajk
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The A1000 uses a colour  TV encoder chip, whereas the A500 have a Commodore video hybrid board that only provides monochrome output. Not sure if there are different versions of the A1000 in that regard though.
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Old 25 May 2014, 08:20   #4
Toni Wilen
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Some early PAL models (I guess original models with daughterboard only) can have PAL Agnus but NTSC configured video encoder (MC1377 pin 20 grounded = NTSC mode + NTSC external components) and NTSC main clock crystal. (PAL=28.37516MHz, NTSC=28.63636MHz, inside the metal box)
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Old 25 May 2014, 16:28   #5
vimfuego
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Ok thanks, I think I'll assume the B&W ones have an issue then. Cheers
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Old 26 May 2014, 07:30   #6
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A little more on this, I pulled the lid off to start looking around the video output circuits.
The datasheet for the MC1377P chip says ground pin 20 for NTSC, open for PAL. Well on my PCB there is no jumper, Pin 20 just goes direct to GND, there is no provision for a jumper on the PCB.
Looking at the PCB images on Amiga Hardware Database it looks like this one is an NTSC PCB, even though on the back it says "PAL' so dunno what the go is now.
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Old 26 May 2014, 10:07   #7
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Ok, So I could be wrong, because I never used it, and it could be different for PAL, but I always thought you needed one of these for color out.
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Old 26 May 2014, 12:16   #8
Toni Wilen
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Quote:
Originally Posted by vimfuego View Post
Looking at the PCB images on Amiga Hardware Database it looks like this one is an NTSC PCB, even though on the back it says "PAL' so dunno what the go is now.
I guess early PAL models are NTSC models with NTSC Agnus replaced with PAL version (and region matching PSU too)

Check also main crystal frequency (under the metal box)

Quote:
Originally Posted by quarkx View Post
Ok, So I could be wrong, because I never used it, and it could be different for PAL, but I always thought you needed one of these for color out.
All A1000s have color composite video output, unfortunately A500 RCA video output is B&W only.

Device in your image RF modulator, Amiga to TV antenna cable adapter. (Which has even worse quality than composite)
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Old 08 July 2014, 13:11   #9
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Quote:
Originally Posted by Toni Wilen View Post
I guess early PAL models are NTSC models with NTSC Agnus replaced with PAL version (and region matching PSU too)
That is correct. Early PAL A1000 models have only the most basic modifications required for colour composite output. They still use an NTSC main crystal (which makes them slightly faster than proper PAL A1000s), so the composite video is not really PAL conformant, genlocking is not possible and video quality (on composite) is generally shitty, perhaps so shitty that your monitor/TV won't recognise it as a colour signal at all.

There are instructions on how to modify the A1000 to give a more conformant PAL signal, and later machines (at least from 1987 onwards) do support proper PAL output.
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