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by sandord
Mon Jul 06, 2020 4:45 pm
Forum: ELECTRONICS
Topic: Strange part connected to flyback of Atari SC1224
Replies: 20
Views: 2573

Re: Strange part connected to flyback of Atari SC1224

Oh sorry if you have a signal generator you can just feed a horizontal signal in and check along the test points to just before the fly back. Will reveal weak parts. And yes some of those flyback could stay charged for years and still burn a probe tip. Samsung and Philips loved them. Must of the ti...
by sandord
Wed Jul 01, 2020 6:41 am
Forum: FPGA DEVELOPMENT
Topic: Project: HDMI/DVI out for STFM
Replies: 581
Views: 84307

Re: Project: HDMI/DVI out for STFM

I guess a compromise to consider would be cutting off 10 lines at the top and 10 at the bottom, distributing the lost area evenly. Realistically, most CRTs didn't show 100% of the full screen picture anyway. I'm pretty sure that scaling will yield unacceptable results. Perhaps a mode switch could ha...
by sandord
Mon Jun 29, 2020 4:56 pm
Forum: ELECTRONICS
Topic: Strange part connected to flyback of Atari SC1224
Replies: 20
Views: 2573

Re: Strange part connected to flyback of Atari SC1224

I seem to remember that Phillips used a similar part in there tv sets for instant on. These are very reliable parts. I would start at the beginning if you have a signal generator. Tom You mean that those TVs kept their tubes charged at all times to make the TVs turn on quickly? I don't have a signa...
by sandord
Mon Jun 29, 2020 12:54 pm
Forum: ELECTRONICS
Topic: Strange part connected to flyback of Atari SC1224
Replies: 20
Views: 2573

Re: Strange part connected to flyback of Atari SC1224

sandord wrote:
Sun Jan 06, 2019 8:36 pm
Okay, so the manual actually does mention the tripler as an H.R.T. but no specs are listed.
I just saw that the parts list in the service manual actually lists it as H.D.T. under Coil & Trans.
Maybe that rings a bell for somebody?
by sandord
Fri Jun 26, 2020 7:24 am
Forum: CHAT FORUM
Topic: I hate it when the sky has bad pixels
Replies: 3
Views: 110

Re: I hate it when the sky has bad pixels

:lol: They say that if you press a dead pixel with your finger hard enough, it might go away. Sounds like it's worth a try.
by sandord
Thu Jun 25, 2020 6:11 pm
Forum: ELECTRONICS
Topic: Atari SC1224
Replies: 16
Views: 910

Re: Atari SC1224

The image is like in the picture of the first post. It has a black area on the top of the screen that it can't be corrected using R626 because it is at its top Dang, I just remembered I saw exactly this problem with the SC1224 of a friend of mine. Sounds like a structural design error. Not to say t...
by sandord
Wed Jun 24, 2020 5:26 pm
Forum: CHAT FORUM
Topic: To hot for me at 30c!
Replies: 21
Views: 342

Re: To hot for me at 30c!

stephen_usher wrote:
Wed Jun 24, 2020 4:21 pm
Last week it was 30C in northern Siberia...
Yesterday I read it was even 38C :fire: :fire: :fire:
by sandord
Wed Jun 24, 2020 5:22 pm
Forum: ELECTRONICS
Topic: Strange part connected to flyback of Atari SC1224
Replies: 20
Views: 2573

Re: Strange part connected to flyback of Atari SC1224

This quote from the post nicely sums it up (at least I hope so): Performance wise the only differences if those components are not inside the transformer are: 1 - the CRT will stayed charged up - this is extremely common anyway. 2 - without the capacitor the picture may experience more 'blooming' (p...
by sandord
Wed Jun 24, 2020 5:16 pm
Forum: ELECTRONICS
Topic: Strange part connected to flyback of Atari SC1224
Replies: 20
Views: 2573

Re: Strange part connected to flyback of Atari SC1224

Out of fear of electrocution I kept delaying this project. But suddenly a question popped up: what if the replacement LOPT (which I already have in my possession) has a built-in tripler? I read that some LOPTs do, so why not in this case? Imagine bolting a tripler to the replacement LOPT and think o...
by sandord
Wed Jun 24, 2020 5:01 pm
Forum: ELECTRONICS
Topic: Atari SC1224
Replies: 16
Views: 910

Re: Atari SC1224

qq1975b wrote:
Fri Jun 19, 2020 10:04 am
I replaced all the caps but the problem is still there. The V position is still a little lower at its high top.
What if this was due to a slight tilt or shift of the neck coils? Does the picture look straight overall?

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