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-   -   My Attempt at Predicta Restoration (http://www.videokarma.org/showthread.php?t=247755)

Phil Nelson 05-26-2010 12:02 PM

I was going to ask what you mean by "crimp connector," but Dave beat me to it. Perhaps you could call it out on one of the pictures you have posted.

If you power it up with all the room lights off and watch carefully, can you see the arc?

Phil

PredictaNoob 05-26-2010 01:01 PM

Its here:
http://i523.photobucket.com/albums/w...icta/crimp.jpg

I'll try it in the dark and let you know about the spark.

DaveWM 05-26-2010 01:23 PM

most have been a way to make leaving the anode to the pic left and just disconnect there when removing the head.

good idea if it works. I would clean around that connector and wire, and dress it differently and see if that does it. my gess is the connector is getting close to the cage and the plastic is not rated for HV.

Maybe a cardboard doughnut near that to make sure it does not get next to the cage?

PredictaNoob 05-26-2010 02:15 PM

Now it behaves differently, and I suspect I was incorrect at where the pop was coming from. This time when I turned it on, I made note that each and every tube was glowing. None of them were going nuts, but they were definitely glowing, including the 6DR7. Wiggling the tube made no difference. I heard a little sizzling going on, and I tracked it to the underside of the board under the damper socket (6DA4) either under pin 2 or 3. It was just a small white spark dancing on top of that solder joint. I'll have to pull the board again to get a better look as that area is covered and difficult to see.
This time there was no activity on the CRT until I turned it off, and the line would appear for a second and disolve to a single point, center screen for 10 seconds or so.

DaveWM 05-26-2010 02:24 PM

check the pin voltages at the crt pin 2,3 and 7 if the CRT

sounds like it is cutoff.

Phil Nelson 05-26-2010 11:14 PM

Quote:

Originally Posted by PredictaNoob (Post 2972337)
I used an electrostatic rust removal process to attack the deepest rust spots, using a 6-volt power supply

I meant to ask this question when you posted the photos, but better late than never.

What did you use as a power supply? I have an old trickle charger that I used to recharge my motorcycle battery each spring. Maybe that would work.

Those pieces looked so good after the electrolytic process was done, I'm wondering why you then went on to paint them. Did they still have pitting where rust used to be?

Phil Nelson

PredictaNoob 05-27-2010 04:23 AM

Quote:

Originally Posted by Phil Nelson (Post 2974360)
I meant to ask this question when you posted the photos, but better late than never.

What did you use as a power supply? I have an old trickle charger that I used to recharge my motorcycle battery each spring. Maybe that would work.

Those pieces looked so good after the electrolytic process was done, I'm wondering why you then went on to paint them. Did they still have pitting where rust used to be?

Phil Nelson

That is exactly what I used, a 6-volt trickle charger; hooked the leads to a short length of wire attached to some super-cheap copper alligator clips (since they get destroyed in the process). I went ahead and primed and painted the pieces because I've found that even though the rust is removed/replaced, the 'aged' spots will quickly rust again with a vengeance. There was some pitting, but that was there before the process. Typically, whatever is present stays in place and will be replaced by the ferrous compounds. If the rust has left pits, it will remain pitted.

On an aside, years ago I found an 18th century toy gun outside of a castle in Rhineland-Pfalz. It was a rusted ball, that I thought was an actual gun. I worked on that thing for weeks, electro-bath, dental pick, again and again. After a few days, it was clean enough to recognize as a toy gun. Finally, I was able to free up the firing mechanism. I've been a believer in this process ever since.

PredictaNoob 05-29-2010 04:54 PM

OK, so its time for a break. I need to walk away from this thing for a few days before I hurl it out the third floor window. I have not been able to track down exactly where the problem(s) is (are). I think a breather will do me good.

We're driving over to the Normandy region of France on Monday for the D-Day remembrance activities. Last year I had the honor of buying an honest-to-goodness 82nd Airborne paratrooper veteran a beer in the square of St Mere Egliese. Right smack in front of the church with the replica of PVT John Steele suspended from the steeple from a parachute. If you've every seen "The Longest Day", you know the one I'm talking about. I hope to re-live this feat again this year. And I'll be buying myself a few of those beers as well. My wife also took a picture of me looking out of the observation port of the same bunker the German officer who first spots the invasion fleet was looking out from in the movie. Might try that again, but a little more in the exact spot this time.
I'm bringing along a uniform in case I have the opportunity to 'strap hang' with the 173rd ABN BDE and get to jump into Normandy. Granted, its been 15 years since my last jump and my wife will probably kill me, but who could pass up an opportunity like this, if it presents itself? Who knows?
Anywho, see you all in 8 days or so.
Bob

batterymaker 06-21-2010 07:41 PM

Quote:

Originally Posted by PredictaNoob (Post 2972566)
I don't have selection in Power Point. Could you send me an example?


I'll have to get my portable hard drive and post an example.

DaveWM 06-21-2010 08:23 PM

Bob and progress, it has been more than 8 days...

W9RAN 07-15-2010 02:36 PM

Realizing this is an old thread, I'll just pile on to say that having just gone over a similar Predicta, I found exactly the same modification. The wire to the Vert Lin pot had been cut and an oversized 300 ohm 25 watt sand resistor hacked in it's place. Vertical linearity and height were horrible, but a few minutes with the sub box produced a much improved image with about 900 ohms. I assume this pot is prone to failure, and the 300 ohm value was deemed correct at some point.

Bob

wiseguy 07-30-2010 06:18 PM

Glad i don't have a wife to get mad at me....
 
I had to try this method of removing rust from a tuner shield from a kenwood kw-1100u amp..interesting as within 3.5 hrs it has dissolved part of the SS spoon off completely..LOL, i find it entertaining.. and interesting..and the rust spots are almost gone.. :)

DaveWM 07-30-2010 07:55 PM

OP seems to have dropped off the planet.

bandersen 07-30-2010 08:15 PM

Quote:

Originally Posted by wiseguy (Post 2979340)
I had to try this method of removing rust from a tuner shield from a kenwood kw-1100u amp..interesting as within 3.5 hrs it has dissolved part of the SS spoon off completely..LOL, i find it entertaining.. and interesting..and the rust spots are almost gone.. :)

That's a real nice power supply you've got there!

Quote:

Originally Posted by DaveWM (Post 2979350)
OP seems to have dropped off the planet.

Maybe he never made it back from Normandy ?

wiseguy 07-31-2010 07:16 PM

rust removal
 
The Power supply shot is to Show The voltage and current of the "part" in the bowl was drawing and it's setting..(which was 6 volts).. interesting as soon as you lower the rusty metal part into the salt and water mixture it really draws some power during this process..:)... this why I am glad I don't have a Wife to get upset at me for using silverware from the kitchen drawer for this ...

DaveWM 08-11-2010 08:58 PM

hello....

mbates14 08-14-2010 04:20 PM

hi........


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