Mighty Monarch of The Air - Page 3 - Videokarma.org TV - Video

vts1134 · #1 06-19-2011, 07:47 PM

Quote:

Originally Posted by bandersen

Did you do any work around that area ?

I did not. I'm almost positive that the arcing is happening inside the tube itself. I'll fire the set up one more time and be sure.

roundscreen · #2 06-19-2011, 07:47 PM

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vts1134 · #3 06-19-2011, 07:48 PM

Quote:

Originally Posted by roundscreen

Did they make a set with a glass crt that did not have a ground going to the chassis? Is there a door knob cap connected to the HV rectifier? If not I think you may have washed off the aquadag coating when you cleaned the crt.
From what I see in your pictures I do not see the aquadag coating.
Ed

There is a door knob cap at the base of the HV rectifier.

roundscreen · #4 06-19-2011, 07:52 PM

Quote:

Originally Posted by vts1134

There is a door knob cap at the base of the HV rectifier.

That is the first time I have seen a set with a glass crt that did not have a aquadag coating on it.
Ed

vts1134 · #5 06-19-2011, 08:23 PM

The arcing is coming from inside the tube, I'm sure of it now. The picture is kind of hard to see because the room was dark but you can see the bluish glow coming from inside the 1X2. Am I right in assuming that this tube is no good?

bandersen · #6 06-19-2011, 08:39 PM

Quote:

Originally Posted by roundscreen

That is the first time I have seen a set with a glass crt that did not have a aquadag coating on it.
Ed

I have several early rectangular 16" CRTs with no coating on them. I'm not sure why though. The datasheets state that they should.

roundscreen · #7 06-19-2011, 10:17 PM

Quote:

Originally Posted by bandersen

I have several early rectangular 16" CRTs with no coating on them. I'm not sure why though. The datasheets state that they should.

That is interesting. Do your set's have a door knob cap connected to the hv rectifier tube? In A set with a metal cone crt the door knob cap goes to ground.
Wonder why are they using a door knob cap in a set with a glass crt instead of using the aquadag for a path to ground?
Ed

miniman82 · #8 06-19-2011, 08:29 PM

Yep, it has air in it and the HV is causing it to ionize. Replace it, and get that HV all the way to the screen!

vts1134 · #9 06-20-2011, 05:23 PM

Quote:

Originally Posted by miniman82

Yep, it has air in it and the HV is causing it to ionize. Replace it, and get that HV all the way to the screen!

Got a new 1X2 today but noticed that the old 1X2 was a 1X2A and the new one is a 1X2B. The old tube is on the left and the new tube is on the right. Are these interchangeable?

Here is the new tube installed and waiting for a higher intellect to give it the green light.

VintagePC · #10 06-20-2011, 06:36 PM

Yep, they should be interchangeable.

Take a look at the letter code specifications - the trailing letters indicate features of the tube. A/B/C are revisions that are backwards compatible, and there are a few others like GT, M etc. indicating glass tube, metal, and some other things.

http://en.wikipedia.org/wiki/RETMA_tube_designation

vts1134 · #11 06-20-2011, 07:13 PM

Fired the set up and got this.

Fired her down immediately. Is this normal? Just a burn off process or a symptom of another problem?

old_coot88 · #12 06-20-2011, 07:34 PM

Holy mackrel. Possibly a dead short either in the doorknob cap or from the 1X2 filament winding to ground. oc

VintagePC · #13 06-20-2011, 08:06 PM

Quote:

Originally Posted by vts1134

Fired the set up and got this.

Fired her down immediately. Is this normal? Just a burn off process or a symptom of another problem?

It can be a bit normal in POWER tubes... but you shouldn't see that in a rectifier. (Especially not that much- I assume that was a normal exposure.) Here's a 30 second exposure of the output tubes in my radio... and this was at a good volume for comparison.

To echo the other folks, look for a dead short. Keep the old 1X2 on hand-- it might still be good!

(EDIT: Ninja'd:

Quote:

Originally Posted by vts1134

Maybe that's what was wrong with the problem with the other tube.

)

--> Though I do have to admit, that _is_ a very nice blue colour to see for real. Cameras don't do it justice.

miniman82 · #14 06-20-2011, 07:51 PM

That's a lot of bombardment, I'd look for a short. You can temporarily remove the doorknob and see if that cures it, you won't do any harm to the set.

vts1134 · #15 06-21-2011, 09:02 AM

R89 and R95 both read good. C66 is the doorknob cab, it is not shorted and removing it still gives the same results when I fire it up. Other components in the area are B3 (horizontal size control), C64 (horizontal sweep coupling), and T3 (the flyback). Any other components I should look at? I'm off to work but I'll be home early to spend some time on the set tonight.