[Coco] collecting info for converter

Gene Heskett gene.heskett at verizon.net
Wed Feb 8 17:50:27 EST 2006

On Wednesday 08 February 2006 17:27, Gene Heskett wrote:
>On Wednesday 08 February 2006 14:44, Sylvain Rousseau wrote:
>>Hello Roy,
>>This is the pinout for the video connector of an Amiga
>>500/600/1000/1200/2000/3000 and 4000.  I got it at
>>and the connector is a ?/%$?# DB23, yes a DB23 male and I don't know
>> where I can find one.  I can hack my A2000 to add it an other
>> connector to test the RGB to VGA
>>adapter and I'm willing to do it but I prefer to use a DB23 if I can
>> find one.
>>Pin     Name            Description
>>1       /XCLK           Extern Clock
>>2       /XCLKEN         Extern Clock Enable (47 Ohm)
>>3       RED             Analog Red (75 Ohm)
>>4       GREEN   Analog Green (75 Ohm)
>>5       BLUE            Analog Blue (75 Ohm)
>>6       DI              Digital Intensity (47 Ohm)
>>7       DR              Digital Red (47 Ohm)
>>8       DG              Digital Green (47 Ohm)
>>9       DB              Digital Blue (47 Ohm)
>>10      /CSYNC  Composite Sync (47 Ohm)
>>11      /HSYNC  Horizontal Sync (47 Ohm)
>>12      /VSYNC  Vertical Sync (47 Ohm)
>>13      GNDRTN  Digital Ground (for /XCLKEN) Don"t connect with pin
>> 16-20. 14      /PIXELSW        Genlock overlay (47 Ohm)
>>15      /C1             Clock out (47 Ohm)
>>16      GND             Video Ground for RED Analog (useful to know
>> because some TVs need specific grounds for specific colors when
>> using SCART/PERITEL SECAM video signal)
>>17      GND             Video Ground for GREEN Analog
>>18      GND             Video Ground for BLUE Analog
>>19      GND             Video Ground for CHV SYNC
>>20      GND             Video Ground
>>21*     -12V            -12 Volts DC (10 mA max) (A500/A600/A1200)
>>21*     -5V             -5 Volts DC (10 mA max)
>> (A1000/A2000/A3000/A4000) 22      +12V            +12 Volts DC (100
>> mA max)
>>23      +5V             +5 Volts DC (100 mA max)
>Let me jump in here and add that the h&V sync signals on this port,
> will if terminated, cause the agnus to shut down to protect its
> output drivers.  Thats why nearly every cable ever made had a chip,
> sometimes even a cmos chip, buried in the hood of that db25
> connector, whose job it was to buffer those 2 or 3 signals.

Bingo!  I knew I was wrong, its a db23, made out of unobtainium I expect 
unless Amphenol might have a few dusty ones left.  I got the last one I 
used from them as a sample way back then.  Way back...

>I was amazed to find this when I bought my first 2000 used off an
> amiga mailing list and found that it came with a commie genlock board
> in it because it could drive a monitor.  An email to Dave Haney
> confirmed my agnus shutdown deduction FWIW.  I assume the seller had
> put it in when he found he couldn't drive a normal monitor (some non
> commie model I suppose) with the regular db25 cable attached.  So I
> made one up using a TTL chip buffer/invertor and put it into mine,
> and ran w/o the genlock card until I finally bought a picasso-II,
> which is still in it, set to run at 1600x1200 24 bit color IIRC.  The
> chip runs from power available on pin 23.


Cheers, Gene
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Copyright 2006 by Maurice Eugene Heskett, all rights reserved.

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