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  #16  
Old 05-08-2007, 09:34 PM
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N9ZQA N9ZQA is offline
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Adam -

What a nice set - looks like you've got a lot of work in on it.

Maybe a long shot, but does moving the 6GH8 or any of the other color-related tubes around in the sockets slightly affect the color at all?

After I got my Admiral console running again, I had no color/weak/strange color. After working with it for a while, I noticed the color coming and going when I would wiggle the bandpass amplifier tube. Cleaning the tube socket and pins provided a good strong color picture all the time.

Jim
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  #17  
Old 05-09-2007, 12:06 AM
Bill R Bill R is offline
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I am not sure adding a cap is the right thing to do. Yes it makes it work, but consider this, at one time the set worked without the cap. You might want to do some more troubleshooting before you call this one fixed. Start by checking the simple things, like tube shields, tube sockets, and especially ground connections. Be sure to resolder all the grounds where the circuit board connects to the chassis. These can cause some strange intermittent problems. Double check all the voltage and resistance readings, and you may need to get the scope out when it is acting up to find out what the problem really is. Just a thought.
Bill R.
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  #18  
Old 05-09-2007, 01:22 AM
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Shaking all the tubes was one of the first things I tried, it doesn't do anything here. Also already tried exchanging several tubes even if they tested good, different sheilds on the 6GH8, and resoldered the ground connections on the color board.

The only 2 things that ever made a difference were resoldering the crystal (which only lasted for a short time), and adding this cap which seems to work permanently. I know my problem isn't the crystal itself because I changed it with a new one and no effect. Now there are a couple caps at the same junction point as the crystal (the pin 1 of the 6GH8 side of the crystal, which is the only one on which resoldering made a difference), C127 and C131, which may have been also affected when I was resoldering the crystal, I am going to try replacing those as well. Any resistors on the color board I've already checked and replaced if they were near 10% or more off.

Last edited by Adam; 09-13-2009 at 10:37 AM.
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  #19  
Old 05-10-2007, 01:51 PM
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Quote:
Originally Posted by Bill R
I am not sure adding a cap is the right thing to do. Yes it makes it work, but consider this, at one time the set worked without the cap.
If it's a new or replacement crystal, it may have a different characteristic, and that the manufacturer intended it to have different capicitive loading. Crystals come in different flavors, paralle or series resonant, and so on. So the extra cap may be called for.
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  #20  
Old 05-11-2007, 10:20 AM
Don Lindsly Don Lindsly is offline
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Have you gone through the chroma oscillator alignment procedure? It's fairly simple. Whatever does not respond properly will usually point to the trouble. It does not require a scope or any test equipment.
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  #21  
Old 05-11-2007, 04:27 PM
Bill R Bill R is offline
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Quote:
Originally Posted by wa2ise
If it's a new or replacement crystal, it may have a different characteristic, and that the manufacturer intended it to have different capicitive loading. Crystals come in different flavors, paralle or series resonant, and so on. So the extra cap may be called for.
This is very possible since the replacement came from a much newer set. You just want to be sure everything else is as it should be to avoid any future problems.

Bill R
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  #22  
Old 05-13-2007, 06:37 PM
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Next I changed that 4pf capacitor (C127), and all I got afterwards was a b/w (not white/green like before) picture. After a while, I found a 4pf cap to ground rather than an 8pf cap would bring the color back. I was curious what would happen with the old crystal (which I don't think was the original one either), so I swapped them back. With the old crystal, I got either a white/green picture (never just b/w like with the new crystal) without 4pf to ground, or good color with it.

Last night I went through the color allignment procedure that was in the sams, first time I ever tried that so I was worried I would make it worse, but it worked, and I managed to get it to work without the extra cap. It still works today, so I think this might be a permanent fix. I also went through the part of the allignment which centers the tint control, which is nice, because before it had to be all the way over to one side. However, after the allignment, shaking the 6GH8 does cause the color to loose sync, but if I just let it be it works. I might still resolder all the pins on that tube socket though. Thanks for all the suggestions... And what is generally used to adjust these coils?, I couldn't use regular tools I had because they were all made of metal, and was looking around for something non-conductive to stick down there, and finally managed to cut some chop sticks so they would work, but I would like to get something a little better.
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  #23  
Old 05-13-2007, 07:55 PM
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There are (were?) non-metallic "diddle sticks" (adjustment tools) available. Since I haven't needed to buy one in decades, I'm not sure where to look for them.

A warning - you apparently did OK wiht your adjustment, but it is typical for the cores in old coils to stick and crack when you try to adjust them with more than a tiny amount of force. That can be a real pain if you don't have replacement cores. (Even worse, the coil form may get brittle with age and crack, and then there is no hope without an exact replacement.)

I wonder if someone here with practical experience can suggest if it's possible to lube the core with something prior to adjusting?
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  #24  
Old 05-13-2007, 11:07 PM
Bill R Bill R is offline
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Glad to see you got it to work. The tools can be bought from MCM.

Bill R
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  #25  
Old 05-14-2007, 07:06 PM
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KentTeffeteller KentTeffeteller is offline
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Hi,

I am really happy your Philco is working well again. Everyone's posts also helped me get my identical Philco roundie combo working like new as well. Thanks everyone!
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  #26  
Old 05-19-2007, 02:11 AM
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Good to hear your Philco is working too. There's more of these Philcos out there than I thought.

Well the color continued to work through the rest of the week, so I put the back back on and am done with this set for a while. Here's some more pics...

I can never seem to get the pics to come out exactly right, they're either always slightly out of focus, or have lines in them that aren't actually on the screen.

Last edited by Adam; 09-13-2009 at 10:37 AM.
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  #27  
Old 05-01-2008, 11:38 PM
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bad horizontal linearity?

The picture is "pushed together" horizontally on the left side of the screen. Actually, this set has always had this problem, but when I was working on it last, I was so happy to get it working as good as I did that I decided to watch it the way it was for a while, but now I'm getting back to it. I want to have this set working 100% before I start in on my ctc-10 (I've decided to put that RCA 6T65 that I was working on last to the side for a while, and get my 2 color sets working first). Also notice how the vertical lines are bent towards the top of the screen, I'm not sure if that's related to the horiz lin. problem or not, adjusting the fine tuning straightens the the vertical lines, but that is the best it will do. Any thoughts on where I should start looking for the source of the problems?

Last edited by Adam; 09-13-2009 at 10:35 AM.
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  #28  
Old 05-04-2008, 02:21 PM
Don Lindsly Don Lindsly is offline
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Does the normal TV picture show the same flagging on the top or is it just when using the generator? Often that comes from the generator.

If the 6GH8 socket continues to give trouble, tighten the pins with a dentist pick or sharp tool. If you change the socket, break it apart and unsolder one pin at a time. That will save the PC board a lot of suffering.
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  #29  
Old 05-16-2008, 10:16 PM
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After I did the chroma oscillator allignment last year, I haven't had any problems at all with the color. The flagging on top happens sometimes with a normal TV picture, but not always, it is worse with the generator. Here's a pic of the same problem seen while I'm feeding the TV from a DVD player.

Last edited by Adam; 09-13-2009 at 10:35 AM.
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  #30  
Old 05-17-2008, 10:31 AM
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Have you tried adjusting the AGC to get rid of the flagging? (Use off air or DVD, not the generator.) This could be a sync separator problem that is either in the sync separator itself or simply caused by the wrong signal level going into the sync separator.
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