UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Converting 405 lines to 625 lines using a Hedghog II

1100 man · 5th Apr 2020, 10:40 am

Hi Tony,
On the 3v29, the DOC gets in the way producing a ghost image half way across the picture on 405 line playback.

I spent some time trying to bypass the part of the video IC that deals with the DOC. In the end, I just grounded the DOC output pin (or input pin, I can't remember now) on the chip & that cured the problem.

Apart from that, it works very well in 405 mode.

Of course for 625 playback, it's very noticeable without the DOC functioning!

Cheers
Nick

5th Apr 2020, 10:40 am	#3
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Re: Converting 405 lines to 625 lines using a Hedghog II Hi Tony, On the 3v29, the DOC gets in the way producing a ghost image half way across the picture on 405 line playback. I spent some time trying to bypass the part of the video IC that deals with the DOC. In the end, I just grounded the DOC output pin (or input pin, I can't remember now) on the chip & that cured the problem. Apart from that, it works very well in 405 mode. Of course for 625 playback, it's very noticeable without the DOC functioning! Cheers Nick