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  #31  
Old 12-21-2017, 02:20 PM
madRad45 madRad45 is offline
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Quote:
Originally Posted by miniman82 View Post
the Sylvania number listed in Sams is 241-0042 or 241-0037 depending on the chassis.
Another piece of info... I have the 1969 Merit Replacement Guide cross reference, and both 241-0037 and 241-0042 cross to Merit HVO-124. Maybe the Sams is wrong, or the HVO-54 was the best match at the time and Merit came out with an exact match after the Sams was published. I don't have the catalog to compare the specs.
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  #32  
Old 12-21-2017, 02:38 PM
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Kevin Kuehn Kevin Kuehn is offline
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  #33  
Old 12-21-2017, 02:44 PM
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Quote:
Originally Posted by madRad45 View Post
Another piece of info... I have the 1969 Merit Replacement Guide cross reference, and both 241-0037 and 241-0042 cross to Merit HVO-124. Maybe the Sams is wrong, or the HVO-54 was the best match at the time and Merit came out with an exact match after the Sams was published. I don't have the catalog to compare the specs.
Hmm. HVO-124 also crosses to Thor Fly 171.
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  #34  
Old 12-21-2017, 03:37 PM
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miniman82 miniman82 is offline
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The fly-171 looks closest, even shows the RFC on the plate lead of the HOT.
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  #35  
Old 12-21-2017, 10:16 PM
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Watching this thread; I have my Halolight on the bench now, no HV, no B-boost, damper is red plating. Hmmm...
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  #36  
Old 12-22-2017, 09:49 AM
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miniman82 miniman82 is offline
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Your oscillator probably isn’t running, got a scope?
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  #37  
Old 12-22-2017, 10:16 PM
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Your oscillator probably isn’t running, got a scope?
I do...sometime over the weekend I'll due some probing in that circuit.
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  #38  
Old 12-23-2017, 11:13 AM
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Is it recapped?
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  #39  
Old 12-23-2017, 06:02 PM
dieseljeep dieseljeep is offline
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I do...sometime over the weekend I'll due some probing in that circuit.
With no drive, the horiz output would be the one red plating.
To get the damper red plating, you would almost have to have drive on the HO tube. It still doesn't hurt to scope the drive on the HO. There must be a problem in the boost circuit.
It's been ages since I had to trouble shoot this circuit.
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  #40  
Old 12-23-2017, 09:48 PM
old_coot88 old_coot88 is offline
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Sounds like a hard short-to-ground somewhere on the cathode side of the damper.
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  #41  
Old 12-23-2017, 09:50 PM
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There are some paper caps left but I think only in the audio circuit. I haven't hooked up the scope yet but today I dug out my Sencore sweep circuit troubleshooter. HO tube cathode current looked normal & adding drive from the troubleshooter had no effect, though I did notice the damper wasn't glowing like before. Using the troubleshooter's yoke substitution test didn't help; when using its flyback test it points to either a bad fly or something in the load circuit, according to the instructions. Further clues: when I started, the fuse in the yoke circuit was blown. Also, I have replaced the damper, rectifier & HO tube with NOS. Outwardly the fly looks normal. I have also tried hooking it up to my Sel-Son crt subber, which I figured would eliminate the yoke from suspicion. No variance.
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  #42  
Old 12-25-2017, 10:06 PM
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Success! Now, the rest of the story...

After replacing the filters & vertical/horizontal caps I had decided to power the set up for the first time. Prior to that I happened to peer into the HV cage & noticed that the HO tube had gone to air. This set, per Sams, was built with either a 6CD6 or 6BQ6-mine had the former. No problem-I have thousands of tubes, mostly NOS, & 10' away I'd find a stack of these. But wait...I don't have a single one! How could that be? I coulda sworn...so out comes my trusty Riders tube substitution guide which says 6DN6 or 6EX6. Well, I'm POSITIVE I have some of each...nope! Not a one! I really didn't want to wait for one to be shipped in so I grabbed a thicker tube sub book off the shelf, one published by TAB books. Yep, here it is-says a 6DQ5 also works. Well, that I had-5 NOS ones right at hand. Fast forward.

Later on Christmas Eve, after my wife settled in for her "long winter's nap", I pulled out "GE Essential Characteristics" to study the base diagrams of 6CD6 vs 6DQ5-maybe there's something that's blank on one & a tie point on the other? Well, it turns out they're totally different! Not a sub at all (unless, maybe, if you re-wired the socket-in which case I might as well re-wire to a 6BQ6). Lousy misprint! No wonder the circuit didn't work!

I went to the attic & dug out a box of surplus tubes. I knew for fact that there wouldn't be a 6CD6 in there because, well, I put those tubes there & it just didn't belong. But, there it was, pretty as you please, a NOS Rogers of all things. 10 minutes later & I was staring at a bright raster!

I did some further tweaking today, swapping out some tubes & buttoning up some things. I should have it all back together later in the week. Thanks, guys, as your advice really did work to put me on the right track & helped me learn a thing or two. Now, back to your reguarly scheduled program...uh, thread!
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Last edited by bgadow; 12-28-2017 at 08:52 PM.
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  #43  
Old 01-02-2018, 09:12 AM
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miniman82 miniman82 is offline
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Lol, glad it worked out. This Halolight has a 6DN6 in it right now, funny you should mention. Side note, I sent a request to that Ersc place because supposedly they had a good fly on the shelf. Never heard anything back...

Search continues!
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  #44  
Old 01-07-2018, 10:07 AM
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Mark spotted a Merit HVO-124 replacement on eBay and I bought it, hope it’s good for only $12. lol
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  #45  
Old 01-11-2018, 09:14 PM
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Raster is full and bright, gonna put it back together and enjoy it for a while.


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