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  #31  
Old 07-19-2006, 11:32 PM
frenchy frenchy is offline
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Location: Moreno Valley CA
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Test results:
replaced 6cb5 and damper, still zero HV spark jump to ground
3/4 amp fuse - about 400v at both ends
3/10 amp fuse above it - barely reads any voltage, < 1v both ends (what's this one for? Probably shouldn't have just measured it without knowing what it was but did anyway, oh well)
6cb5 cap, connected - no spark whatsoever
6cb5 cap, disconnected - 165 v ??? Ed said this should be B+ too?
I am running at normal line voltage, 117 v maybe.

Last edited by frenchy; 07-20-2006 at 12:07 AM.
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  #32  
Old 07-20-2006, 07:39 AM
roundscreen roundscreen is offline
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The 3/10 amp fuse is for the horz current so Don't worry about that yet. I dug out my 5 and did a double check on the 6cb5 cap voltage and I get 385vdc on that cap. Also my ac line is set to 114 ac so it would be lower than what you would get at 117vac. I think you found your problem. Just to make sure, Check pins 4-5 on the 6cb5 and make sure you have drive voltage. It should be around -30 vdc. Also check pin 7 on the 6cg7 {horz osc}. Should be around - 70vdc. Lets make sure the b+ is getting into the horz osc. Now please go to the yoke plug and see what you get on pins 7 and 3 and Make sure the yoke is connected. The voltage should be at b+ or a bit lower.
Ed

Last edited by roundscreen; 07-20-2006 at 08:54 AM.
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  #33  
Old 07-20-2006, 08:51 AM
roundscreen roundscreen is offline
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frenchy.
Here is a picture of the yoke plug. As you can see there is a jumper.
This jumper is a interlock so the horz will not turn on with the yoke disconnected. It could damage the set if it was turned on with the yoke disconnected and there was no interlock.
ED
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Last edited by roundscreen; 07-20-2006 at 08:55 AM.
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  #34  
Old 07-20-2006, 09:09 AM
frenchy frenchy is offline
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ok I will check this stuff tonight. Well, tommorrow night, girlfriend is coming over tonight (yes again : )
-- What is the overall effect of testing with the yoke disconnected as far as me getting normal voltages in the hv section, spark etc.?
--At first glance what does it sound like the culprit might be with that low voltage at the HO cap? (I hope it's not that I'm just a dummy and all I had to do was plug the 1V2 back in while I still had the chassis in the set and the yoke still connected.)
--Do I have to do all the measurements with the yoke connected or not? Right now I'm testing it on a bench away from the cabinet, I didn't know there was an interlock in the yoke plug. I saw a 'HV interlock' on the schematics but I coulodn't see one obvious on the chassis so thought maybe there wasn't really one there.)
Thanks! I told my girlfriend I might know 10,000 times more about fixing tvs than HER, but you guys here know 10,000 times more than ME! : )
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  #35  
Old 07-20-2006, 06:23 PM
roundscreen roundscreen is offline
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frenchy.
You do need the yoke connected to get normal voltages. I think that may be why you have low voltage on the horz tube cap that goes to the flyback. Also I think most tube color sets have that type of system. In a way it does cut off the hv so it could be the hv interlock, But it may be the line cord you are looking at. Also I may be useing the wrong word. {interlock} Throw in the 1v2, put it in the cabinet and see what happens.
I would try and lower the ac line voltage, Just in case the arcing is still a problem.
That would be great if it was just the 1v2.
Good luck and have a great evening.
ED
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  #36  
Old 07-20-2006, 06:52 PM
frenchy frenchy is offline
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ok I will lug it back into my bedroom and plug it all back in and try it, I've guess I've fixed black and white sets before and was used to expecting good HV to be at the anode wire even with the chassis out. The interlock for HV on the schems was either on the cap wire for either of the two big HV tubes (6cb5 or 6bk4, don't remember offhand) but I never saw that in the chassis itself. Crossing my fingers, thanks
Frenchy
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  #37  
Old 07-21-2006, 07:53 PM
frenchy frenchy is offline
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Thanks everybody for helping me with my ignorance on some basics, set is working fine again after fully hooking it up to the pic tube and popping the 1V2 back in there. It was a combination of dumbly not putting the 1v2 back in the set months ago to begin with + not noticing the 1v2 was absent while debugging the installed chassis since that tube is buried way down in the cage + the popping spooking me into thinking it was something like a bad flyback and not a missing tube + not knowing about the interlock design of the yoke plug. I just have to put the HV cage back in now. Whew!
Frenchy
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  #38  
Old 07-22-2006, 07:06 AM
roundscreen roundscreen is offline
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Frenchy
Glad to hear that. Can you post a picture of your set. I bet it is a cool looking set and has a nice picture.
ED
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  #39  
Old 07-22-2006, 11:20 AM
frenchy frenchy is offline
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Here she be, this is an old pic from couple of years ago but it looks the same now. This thing is really a survivor, there is a crescent-shaped cracked indentation around the channel changer where you can tell somebody tipped the thing over once and it slammed onto the floor on it's side once but it refuses to die! Even the survivor VP-1000 laser disk player on top of it has since croaked.
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Last edited by frenchy; 07-22-2006 at 11:37 AM.
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  #40  
Old 07-22-2006, 07:26 PM
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reeferman reeferman is offline
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Two good weekends in a row!
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  #41  
Old 07-23-2006, 12:35 AM
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Tony V Tony V is offline
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Awesome set Frenchy! I'm glad it turned out to be something simple. If nothing else from this experience was that you were able to check on the current condition of the electronics for a maintenance check if nothing else. Hopefully it will give you trouble free service now for awhile before you have to into again. Cool Deal!
Tony
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