[QuadList] Shinybow SG-3680 RGB-to-CVBS, Y/C Converter Funny

[mike at bolandcom.com]

James,

Most of the low cost converters do nothing to the video, but make
it viewable by converting the chroma from 3.58  4.43.  In the
case of the VHS machines, the result was called something like
NTSC 4.43 (frame rate still 60 hz, H still 15734).  You were told
to "adjust the vertical hold control for lock" to make your PAL
TV accept the NTSC 60 Hz frame rate luminance while the
converted simple PAL chroma was usually accepted directly
by the TV. 

mike
___________________________________

On Wed, 25 Jun 2014 10:41:46 +1000, James Paterson  wrote:

-------------------------

Interesting you should make a post about Shinybow products... 
   
  I was considering their NTSC> PAL standards converter for some basic 
conversion from an NTSC s-video camera signal to a PAL system. 
   
  However, seeing that its in the somewhat lower end of the market i 
wondered how well it performed this conversion as if it introduced 
dropped frames as its method of conversion resulting in jerky video
  then it would not be suitable for the job, emailing them to see if 
they had a demo video or could explain what method it uses to convert, 
they couldnt answer
   
  Perhaps someone could reccomend a decent but lowest priced converter 
that does the job without noticable dropped frames or jerky motion
   
  James

        ----- Original Message -----
  From: Steve Burgess
  To: quadlist at quadvideotapegroup.com
  Sent: Wednesday, June 25, 2014 9:30 AM
  Subject: [QuadList] Shinybow SG-3680 RGB-to-CVBS, Y/C Converter Funny

-------------------------

    Hi folks
   
  Attached are pics of both sides of the (rather nice) PCB for this 
eBay.co.uk-sourced SB-3680 RGB-to-CVBS, Y/C converter (serial: 
20048001106). 
   
  It uses a KA2198BD encoder chip wired for PAL operation (pin 7 
grounded) and a 4.43MHz crystal oscillator employing a Schmitt-trigger 
inverter. 
   
  Inspection reveals that R1 and C5 are not fitted, which means the 
4.43MHz subcarrier is not reaching pin 6 of the KA2198BD – so no 
wonder I am having problems with the chroma output. 
   
  Also, the KA2198BD datasheet says that for PAL the components 
connected to pin 17 should be 82uH and 15pF whereas 100uH and an 
unmarked capacitor are actually fitted; if the capacitor is 20pF, these 
values are what the datasheet says should be fitted for NTSC operation. 
   
  Weird. 
   
  eBay seller swears blind it was working ok but decided not to return 
as paid next-to-nothing for it and was curious to get to the root of 
the problem.  I’ve e-mailed Shinybow in Taiwan. 
   
  Steve Burgess
  retired, ex-BBC/Channel 4 UK

-------------------------

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