Re: SX clocks generation

From: Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
Date: Sat, 04 May 2013 19:41:56 +0200
Message-ID: <51854864.5060205@laosinh.s.bawue.de>
On 05/04/2013 07:03 PM, silverdr@wfmh.org.pl wrote:
>
> On 2013-05-04, at 18:13, Gerrit Heitsch wrote:
>
>>> I am wondering if anyone knows (before I start disassembling the SX in order to experiment) whether this effect can be caused by the differences in the clocks generation methods between regular 64 and the SX or something else (like the output amp).
>>
>> How is the internal monitor hooked up to the SX-64 video output? Y/C or CVBS? CVBS would explain some of the artifacts.
>
> You don't see the ugly effect on the internal one. The resolution of that delta tube is probably too poor there to notice much.
>
> According to the schematics, the internal one is fed with Y/C. I did a quick test and disconnected the internal display checking if it would affect the picture on the external one but no change was visible.

Could be the same problem as on the C16. There the Chroma-Signal 
imprints itself on LUMA just by the traces running close together that 
feeding the monitor just LUMA will get you a color picture. Using it as 
Y/C will get you what your pictures show. Even worse on a TFT.

So maybe you need to check the SX64 boards and see how both signals are 
routed between VIC and video output.

  Gerrit





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