View Full Version : Jail bars and dark spot


lnx64
06-08-2012, 10:21 AM
So I've mentioned this before, and I really want to take a stab at fixing this.

What could be causing this?

http://img.photobucket.com/albums/v395/Evilweredragon/jailbars.jpg

The dark band in the middle and the jailbars at the left.

Capacitors? I did try messing with the vertical hold, and the dark band in the middle doesn't move.

That's with the contrast down and brightness up btw.

ctc17
06-08-2012, 10:43 AM
Did you get a good modulator like a blonder thong or other commercial ntsc modulator? You can pick them up cheep now that they are being pulled from use.
A good mod will correct so many of these issues you have.

If its not that....this is the one with the crappy aftermarket flyback?

Its hard to expect perfection from what was a $129 department store set with a chinese made aftermarket flyback being fed with a signal from crappy modulator.
If you want a boss late 70s early 80s set, look for a Mitsubishi monitor or tv.

radiotvnut
06-08-2012, 11:04 AM
It could be bad caps in the power supply or it could be a bad cap in the B+ line that comes off the flyback that provides voltage to the video output stages. Look for something between a 4.7 up and 22 uf with a voltage of at least 200.

lnx64
06-08-2012, 11:40 AM
I'm using the blonder tongue now..

I was hoping this ISNT a flyback issue. I got the HR Diemen as a spare as that finally arrived, but just swapping flybacks isn't easy on this set.

I'll check the caps this weekend.

Charlie
06-08-2012, 11:58 AM
My CM roundie produced a similar set of lines on the left side of the screen years ago when I had a Radio Shack RF modulator connected to it. After disconnecting the modulator and then connecting my Panasonic VCR/DVD combo to it, the lines went away.

DaveWM
06-08-2012, 12:50 PM
incomplete horz blanking during flyback period.

DavGoodlin
06-08-2012, 01:57 PM
It could be bad caps in the power supply or it could be a bad cap in the B+ line that comes off the flyback that provides voltage to the video output stages. Look for something between a 4.7 up and 22 uf with a voltage of at least 200.

Those caps often are on the CRT socket board:yes:

lnx64
06-09-2012, 01:28 AM
So I took a second look with my blonder tongue, as the pic I posted was actually my cheap philips modulator, and at first, I thought it was in fact gone, as I just recorded a video showing off the blonder tongue, but on second look, it IS still there but not as bad.. Then again, I adjusted the audio and video modulation levels on my blonder tongue (from the auction that was reccomended by a VK member), and it is still there, but looks better (the dark center band).. The ringing on the left side, is still there and no different, but it seems to only affect the blue it seems, not the red and green.. That sounds like a cap issue..

ctc17
06-09-2012, 02:14 AM
Don't turn the Aural up to high. Just to where the sound pops in solid. Keep yhe power level backed off, that modulator iis made to drive a whole hotel full of tvs so you don't need it at max for one.

The caps are worth a check

lnx64
06-09-2012, 02:59 AM
Ok I'll try adjusting that.

I noticed my Blonder Tongue has some bulging caps in it too. I might go ahead and replace those.. Not good.

lnx64
06-09-2012, 09:22 AM
http://www.youtube.com/watch?v=KQ_83G8UEgs

lnx64
06-09-2012, 11:17 PM
Whew! Not the flyback..

I found a video of when I was adjusting the TV with the old flyback, it was doing the same thing then.

It's odd though, I seriously don't remember ANY of those artifacts, but since installing a new flyback, I'm nitpicking everything about this TV.

Guess it's just cause im a perfectionist.

lnx64
06-10-2012, 03:55 AM
Well well well, I was wrong! So BOTH flybacks were crap!

I installed the HR Diemen, and crap, ALL symptoms are gone.. Ringing is gone, dark band is gone.

I LOVE HR DIEMEN!

Now to tune the set


http://img.photobucket.com/albums/v395/Evilweredragon/IMG_0654.jpg
The ghosting around the clock on the screen was the camera.. It looks SO much better than the ASTI Magnetics flyback.. No ringing OR bands. Amazing..