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  #46  
Old 10-30-2009, 09:09 PM
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stromberg67 stromberg67 is offline
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Thumbs up

That's almost more beautiful than my Lovely lady Friend! Almost!
Great news!! Look forward to the first screen shots!
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  #47  
Old 10-30-2009, 09:44 PM
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thanks for the articles, Jerome
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  #48  
Old 10-30-2009, 11:10 PM
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I wonder if the carrier realized how many people would be angry if they broke your 15GP22?

Have fun you guys!

John
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  #49  
Old 10-31-2009, 12:17 AM
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This tube was under Vacuum so what was the original problem, just weak or dead?
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  #50  
Old 10-31-2009, 02:20 AM
sweitzel sweitzel is offline
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Eric, I think this post from an earlier thread is describing the tube in question:

http://www.videokarma.org/showpost.p...9&postcount=17
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  #51  
Old 10-31-2009, 02:36 AM
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Ah, thank you, that was one really dead tube!
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  #52  
Old 10-31-2009, 10:38 AM
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Erich H, Just to pick a nit, the 15GP22 just rebuilt was NOT the one Bob described. This tube was one I had which had a bad gun but was still under vacuum. This is the second time this tube has been through the rebuild sequence at Hawkeye. The first attempt failed when the stem cracked towards the end of the evacuation cycle in the oven. The newly redesigned stems we had fabricated seem to have fixed this problem. At least on a sample space of one.
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  #53  
Old 10-31-2009, 12:24 PM
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Im excited to see the end result! This is great news and yes, One small step for man, one giant step for mankind indeed!!! "Kid in a candy store"!!!
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  #54  
Old 10-31-2009, 12:27 PM
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Essential Expansion

Quote:
Originally Posted by John Folsom View Post
Tom,
An expansion on what Pete said about having the guns rebuilt: After the gun is removed, Bob Galanter uses an EDM (electro-dynamic machining) tool to mill out the old cathodes from the gun structure with micron precision. Bob built a custom jig to hold the gun assembly which allows the precision EDM machining to be done. Without Bob's expertise, the 15G project whold have come to a halt becausee the company which puts new cathodes and filaments back in ghe gun and mounts the gun on the new stem was no longer willing to attempt the difficult task of removing the old cathodes. I do not think they had access to EDM machining.

Tune in next week for final acceptance test results on the CRT rebuilt at Hawkeye.
Thanks John........Bob's custom jig and EDM (electro-dynamic machining) was truly the breakthru on this ambitious project. I imagine the crt vendor just had to slip his new heater/cathode tube into the hole Bob bored into the original cathode cylinder?? I would be very interested in the total rebuild cost with profit. Scotty quoted me $400 for my 21FBP22 which is a slam-dunk in comparison. Tom
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  #55  
Old 10-31-2009, 01:56 PM
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Any plans to video the first start... would be neat to see a dark screen come to life!!!! Just like man walking on the Moon.
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  #56  
Old 11-03-2009, 10:30 AM
mbates14 mbates14 is offline
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  #57  
Old 11-03-2009, 01:56 PM
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OK..It's Official...We have Ignition...

(posted from John Folsom's computer being tybed by Bob)

I arrived at John's house on Saturday afternoon around 1:30 eastern and after having a brief lunch we started our work.

The first order of business was to mount the base on the 15G and solder the wires. We then proceeded to test the crt with the Beltron. Because the cathodes had not been run through the complete activation protocol the guns tested rather low. So we ran through the cathode activation protocol that had been given to us by Scotty. That took about a half hour and after the protocol had been run we retested the 15G on the Beltron. Blue and green were fairly good but the red was still substandard. So we ran the Beltron "cleaning" protocol and VIOLA the red gun came alive.

We now had very good emission on all guns and as the next few days of operation showed, the emission got even better as we used it more.

With that done we mounted the 15G on a CBS crt truck and pulled a CT100 chassis from one of Johns sets that had been recapped some time ago.

So... the next thing to do was hook the 15G up to the CT100 chassis to do a real world test. The CT100 chassis was giving us a lot of problems. The picture the chassis was supplying was VERY bad. There was evidently something wrong with the front end of this chassis. HOWEVER, before we could get the problems in the front end of the chassis resolved, we developed a HV problem. The flyback was hotter than blazes and arcing and so we spent the next several hours replacing the CT100 flyback.

ONce again we fired up the chassis and now we had good HV and started tweeking the controls to try and get a decent picture. We were still being plagued with poor signal quality, but the crt was lighting up nicely. But the picture quality sucked. We subbed a signal from a test tuner and got a fairly decent picture so we decided that the problem was in the tuner on the ct100. So next we pulled the top section of the ct100 tuner and subbed a different tuner into the set. Still the picture quality was lacking. IN a last ditch attempt to get the chassis running we decided to do a front end IF alignment. Unfortunately that did not help much and we still had a very bad picture on the 15G.

Now two days into the project we are not getting very far so John decided we wasted enough time with the CT100 chassis and made an executive decision to abandon the CT100 chassis as a driving mechansim and go to plan "B". We decided to use John's Westinghouse H-840CK15 chassis as the driver for our tests.

So after making a number of adapter cables and setting everything up, and doing a fair amount of initial tweeking, we now had a pretty decent color and B&W picture on the new 15G.

Murphy's law states that "whatever can go wrong will go wrong" and so of course not long into our tests with the Westy chassis, we heard a big "snap" and we lose the picture on the 15G. After some brief expert diagnosing on the part of JOhn, we came upon the discovery that the 30KV 2000pf doorknob had taken a dump. But never fear, John had a spare and in about 2 more hours and a trip to Ace for some metric screws, we were up and running again.

That brings us to MOnday morning. We now have a Westy chassis that is operating and driving our newly rebuilt 15G. AFter a few hours of purity, convergence and assorted other chassis tweaks we finally had a VERY NICE picture on the new 15G.

Over all we are very pleased with the performance of the tube. We do however, have a small problem with purity. On INitial power up cold start the tube has very good purity. After it warms up, we get a shading of color shift to the green on the right side of the tube. In our opinion the purity issue is rather minor considering the brilliant Technicolor picture we are getting from it.

Future plans are for John and Bob to make another trip to Hawkeye to rebuild two more "under vacuum" duds and attempt to also seal and rebuild a leaker. We are hoping to make the next attempts before the end of the year, or very shortly after the beginning of the new year.

Before we do that, however, we will need to have more gun assemblies rebuilt. Will be proceeding with that as soon as possible

The actual image on the rebuilt crt is far far better than these photos show. We tried over and over to get some screen shots that looked as good as the crt looks in person, but we could not get any shots that looked very good.

So there you have it. The 15G is rebuild-able.

John Folsom and Bob Galanter
Attached Images
File Type: jpg IMG_6590.jpg (75.2 KB, 149 views)
File Type: jpg IMG_6583.jpg (80.9 KB, 188 views)
File Type: jpg IMG_6594.jpg (37.9 KB, 187 views)
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  #58  
Old 11-03-2009, 02:18 PM
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WOW what a saga!

BRAVO!!!!

Good work !!!

jr
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  #59  
Old 11-03-2009, 02:29 PM
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Zowie! You guys are having way too much fun.

Phil
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  #60  
Old 11-03-2009, 02:34 PM
mbates14 mbates14 is offline
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woa.. wholly hell. the first successful 15GP rebuild ever. bravo. Oh, btw, IT LIVES!
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