My Predicta died today

[Captain Video]

I was watching a DVD on my Predicta and then suddenly the image collapsed into some sort of vertical line and then the screen went dark. Now it turns on, there's audio but the screen doesn't light up. Any ideas on what can be wrong with it???

[StellarTV]

How fast did the image collapse? Did it go from full screen to a vertical line instantly, or did it take a few moment for the image to slowly shrink to the line and then fade?

[Captain Video]

It was very fast: in one moment the screen was full, and then in a second it collapsed into the vertical line.

[Boobtubeman]

Predictas never die.... as long as screwdrivers exist...

SR

[StellarTV]

Tough call, but I'd suspect a bad solder joint on the board around the horizontal output first. Second I would suspect an open winding on the flyback, and third a bad connection to/open winding on the deflection yoke.

Try letting it cool down for a 1/2 hour and then see if it comes back to life. If not, wiggle the 6DQ6 horizontal output tube in its socket lightly while it's on to see if high voltage comes back. If not, check the plate of the horizontal output and see if it's glowing cherry red... if so, this means the horizontal oscillator is dead. Otherwise you'll have to check the resistance and continuity through the flyback and yoke.

Could also be a simple power supply issue, without a print in front of me I can't help to pinpoint that though.

[Zenith26kc20]

Pull the cap off of the horizontal and check it for B+. If that is present I would check voltages around the vertical output tube (plate). If no B+ on the HOT, look around the damper tube for proper voltages. Don't go poking around with the cap on the HOT if you are using a DMM. The high voltage pulses will kill your meter.
Most Predictas I have worked on develop vertical trouble more than anything else.

[kramden66]

what about checking the tubes ?

mike

[Captain Video]

My father fiddled with the linearity and width controls on the back and the image reappeared. Is this normal?

[DaveWM]

the pots on those sets are not the best and can cause issues.

[Tubejunke]

Not to be flippant or anything, but quite often with troubleshooting it is the most simple and obvious things that often get looked over. A good example of this comes to mind in a situation that I recently and unfortunately experienced. I work as an electronics technician (maintenance) in a manufacturing facility (factory). LOL! At any rate, there was a rather complicated part of our process that developed erratic/intermittent problems.

Well, after the supposed best of the best in our crew took pot shot guesses and a number of "cold boots" the German company flew over an engineer with a laptop to hopefully fix what everyone had determined must be a software issue. As it turns out there were several 3 phase contactors that had intermittently high resistance contacts. This was most likely due to exposure to dirt and chemical residue over time as the electrical enclosure had no positive air pressure to keep such things out as do all of the others (most are air conditioned in a separate room).

Point being that in this case a lot of money was spent and production time lost because of the most rudimentary problem that we could have had and the first thing that we should have gone over with a fine toothed comb. In my defense I will add that I asked about checking the array of electromechanical contactors and was told that they had all been checked. I still checked one and showed the boss the strange readings, so he let me change that single one, but seemed resistant to letting me go further. Sometimes too many minds involved (and bosses looking to impress their bosses by being the one who saved the day) can really hinder the troubleshooting process. Just sayin'

[Reece]

I see many threads complaining of sudden death and crackles that would make me wiggle tubes and controls to find the intermittent. Ditto on checking the easiest tests first. Think of all the tube socket terminals and control points in sets, sometimes dozens, all subject to oxidation.

[wa2ise]

Originally Posted by Captain Video

My father fiddled with the linearity and width controls on the back and the image reappeared.

Looks like it's dirty pots, similar to what Dave mentioned. The wiper inside losing contact with the carbon track inside the pot. Some contact cleaner may help, or new pots. Either option should fix the TV set.

[Captain Video]

I was watching and then the image collapsed again, but this time there was lightning inside the TV and smoke appeared coming from ( it looked like ) the flyback area. Now I am really in trouble. It will be hell to find someone in my area willing to repair this thing... and if the flyback is no good anymore, most likely I will not be able to find a good one.

[Eric H]

The Flyback is inside a metal box so if it arced you wouldn't see it.
Possibly a cap shorted and took out a resistor.

[Tubejunke]

Originally Posted by Captain Video

It will be hell to find someone in my area willing to repair this thing... and if the flyback is no good anymore, most likely I will not be able to find a good one.

The first part may be correct as there are no television repair shops left, or not many. But if the fly is bad, I would say that you have a better chance at finding one for a Predicta than most other sets of that era. I say this because while other trends have come and gone in vintage electronics, the Predicta for whatever reason has long been sought after, so there are many around and I would imagine a lot of parts. Good luck on this!