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#31
07-29-2012, 09:27 PM
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I'm at the stopping point now. I won't run it anymore until work is done.
Discovered the horizontal oscillator board chassis ground connections are broken. I'll do all of them while I'm in there. My nephew likes B/W. He's 12, and has seen B/W cartoons, etc, courtesy of me all his life. I hear whining of employees at work about B/W shows all the time. They are just spoiled with color! 
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#32
07-30-2012, 09:56 AM
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More news: Got the chassis out. It has the shield over the color circuitry, but all but 2 of the screws holding it are gone. The 3.58 crystal has a 1-68 date on it. (My CTC-10 has its original glass enclosed crystal.)
Grounds have been touched before, as shown by the melted wires around some of them. I've temporarily fixed the broken grounds on the hz osc board. One wire that runs by a ground point at the video board was actually making contact on the ground stake. I got continuity from the ground to the place where the wire connects in the chroma. Cleaned it up and dressed it away from the stake, and now it's reading almost infinity. I have a feeling that this could make a change in what I see on the screen. Would you guys suggest that I turn the chassis tubes down and then re-solder ALL of the grounds? Some look perfect, but I do know that they had issues with intermittent connections on these. I'm applying pressure to the PC board while the solder cools. I've seen cases of these sets where a repair involved running new ground wires from the grommets to an actual chassis ground point. I thought this looked really crappy. I've lubed the UHF tuner gears, and am warming everything up with a small heat lamp to help flow the lube. I'll let it sit for a few hours cooking. Also evidence of long-dead roaches. I'll get it back outside and blow it out. There's been work done on this... the video board, and the hz osc board have had parts tacked to the old part wires coming thru the PCB. I dont like this, but for now, I'll leave it alone. Last edited by holmesuser01; 07-30-2012 at 10:06 AM.
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#33
07-30-2012, 09:09 PM
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Put it back in the cabinet to have a look again.
Fired it up and have chroma, but no raster. Before, there was no chroma. Now has sound. Full good width, and vertical issues. I know the vertical problems are those nasty wax capacitors. The video... well, the OEM 12BY7 was toasted. The replacement NOS is in it. I can see something when the contrast is moved, and brightness changes. I've made a list of what capacitors are in the set to compare with the RCA manual and Sams. It ran for about an hour total. I never left it. Both can filters are cool, and the flyback got warm, but not terribly warm. High voltage is holding steady now at 22kv. The B+ voltages are dead on from the power supply. The 145v supply from the audio output is 140v. Not going to run it much until I check the cathode current, and get some capacitors. Last edited by holmesuser01; 07-30-2012 at 09:41 PM.
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#34
07-30-2012, 09:56 PM
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those ground stakes look nice and shiny, if it was me I would leave it be until there is some proof that you have an issue. That entire chassis looks very clean, I suspect it was in an air conditioned enviroment.
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#35
07-30-2012, 10:10 PM
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Thanks. Those ground stakes have been re-soldered in the pictures. 2 on the horizontal oscillator board were broken. Not beautiful, but it's working.
Also re-did all of them on the video module. Thats where I found the wire that was making a connection at the ground between the video and the chroma. I got chroma after that. Speaking of clean enviroment, I can smell perfume when it's on after 15-20 minutes. We think it might have been in a bedroom for alot of years. Thanks, Dave, for your comments. Bruce
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#37
07-31-2012, 12:27 PM
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Quote:
I was impressed at how good the reds look on this CRT.
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#38
07-31-2012, 03:02 PM
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Quote:
Phil Nelson
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#39
07-31-2012, 03:55 PM
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Quote:
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#40
07-31-2012, 04:38 PM
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Also be sure to check the high value resistors. I had vertical issues with my 7, and a couple of the resistors were way out of spec.
__________________
stromberg6
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#41
07-31-2012, 05:49 PM
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I placed an order for capacitors today. Several I couldn't find, but will worry about that later.
Also bought enough electrolytics to do this set, PLUS several audio amplifiers that I've been procrastinating with for years. I've never seen a 6BK4 that looks like this one! Last edited by holmesuser01; 07-31-2012 at 06:09 PM.
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#42
07-31-2012, 10:47 PM
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You mean not burnt to a crisp? Most are very dark brown with a lot of use. More than likely replaced.
__________________
"It's a mad mad mad mad world" !! http://www.youtube.com/user/mwstaton64?feature=mhee
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#44
07-31-2012, 11:05 PM
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Quote:
__________________
"It's a mad mad mad mad world" !! http://www.youtube.com/user/mwstaton64?feature=mhee
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#45
07-31-2012, 11:13 PM
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Its fun to sniff around that area with a giger counter. Reducing the line voltage really lowers the xrays.
The HV system is designed with enough output to operate a fresh crt and full brightness. Well how may of these old sets have that...? So all that extra headroom ends up as heat and x rays dumped off by the shunt tube. Dropping the line voltage by 10 volts usually drops the shunt tube temp about 150 degrees F
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