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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Wed Oct 31, 2007 5:12 pm Post subject: |
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| macgyver655 wrote: | Hmmmm. Will it run with the vert deflection board pulled to see if you get a flat line?
I'm just thinking if it is electron flow from the gun then this might verify it. |
Don't think that will work either but I don't want to risk spot burning the tube.
Chris.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Wed Oct 31, 2007 5:18 pm Post subject: |
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I understand. It is very dim and probably would not burn but I would be causious also. The only other thing, which many have done before is to put the tube on its face and tap the neck to try to dislodge any particles, but I can sense your skin crawling already just thinking about tapping on the neck of that glass tube. Good Luck!!!
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Wed Oct 31, 2007 5:24 pm Post subject: |
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| macgyver655 wrote: | | I understand. It is very dim and probably would not burn but I would be causious also. The only other thing, which many have done before is to put the tube on its face and tap the neck to try to dislodge any particles, but I can sense your skin crawling already just thinking about tapping on the neck of that glass tube. Good Luck!!! |
I've seen broken tubes, it's not a pretty site.
Remember this; https://www.curtpalme.com/forum_archived/viewtopic.php@t=5935.html
Chris.
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macgyver655
Joined: 22 Aug 2007
Posts: 8508
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| Posted: Wed Oct 31, 2007 5:28 pm Post subject: |
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Yes I remember seeing that.  Well the only other thing other then replacing or sending out for repair is put it together, fire it up and let it run(if the pic is ok) and maybe it will burn itself off. At any rate, Good Luck!!!
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Wed Oct 31, 2007 6:25 pm Post subject: |
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I still have some more testing to do but it looks like this tube needs to be sent to VDC for repair.
Does anyone have the contact info for Charlie at VDC as I hear he is the person to get this done?
Chris.
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erikjohn
Joined: 08 Mar 2006
Posts: 636
Location: Florida
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| Posted: Wed Oct 31, 2007 6:49 pm Post subject: |
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800-241-5005
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EJ
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Chuchuf
Joined: 11 Mar 2006
Posts: 548
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| Posted: Wed Oct 31, 2007 10:58 pm Post subject: |
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| Tom.W wrote: | | And how do they fix it ? |
Tom, if it is contamination they have a rig they specially built to fix that very problem that applies 30KV to the dag and then the ground out individual pins. Anything in the way that's not metal gets zapped. Their success rate is about 95% if thaht is what the problem is.
New or NOS, it doesn't matter. ALL tubes are prone to this and I have seen as Charlie has on new as well as NOS.
As far as your sencore goes, I considered getting one of those some time ago until I (after having a long talk about it with someone who knows and whose opinion I trust in matters of tubes) found out that the readings can be very unreliable in the tubes that we use. I won't go into detail as to why the readings can be unreliable except to say that they don't provide the correct voltages and that this company after fooling with and then modifying the PS section of the 7000, gave up on it and built their own rig/tube tester. Tom, I know you are a big proponent of these but after what I found out about them, I felt that they were very limited in their use.
Also keep in mind that the contamination can move around in the tube and be there one day and not the next. Shipping is a problem if the tubes are not kept face down.
In the case of the tube problem that Chris is having, I am now wondering if there is a short from contamination between the aluminium in the tube and the phospher that is exciting it?
Charlie will know. Chris, I sent you his number.
Terry
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Wed Oct 31, 2007 11:56 pm Post subject: |
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Ok, I was wrong. The problem is not there when the neckboard and G2 lead are disconnected. But it does follow the tube. I switched the blue and green tubes and it does follow the tube. I also swapped the blue and green neck boards and the problem still stays with the tube.
I will give Charlie at VDC a call and see what he thinks,
Thanks everyone for the help.
Chris.
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tse
Joined: 03 May 2006
Posts: 1014
Location: Sweatbucket, Fl.
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| Posted: Thu Nov 01, 2007 1:07 am Post subject: |
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| macgyver655 wrote: | Hmmmm. Will it run with the vert deflection board pulled to see if you get a flat line?
I'm just thinking if it is electron flow from the gun then this might verify it. |
That would be an interesting experiment. It can be done safely by unplugging P14 (heater power), turn on projector, after initiallization plug in P14 while watching tube face. The filaments warm up slowly enough that there is plenty of time to pull P14 if a line starts to show. I've done it many times.
This problem sounds alot like secondary emission. I've seen it cured with a Sencore 7000. Those cases were with the contamination on the cathode. If it is somewhere else? I don't know if the Sencore will fix it.
Scott
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"Were we directed from Washington when to sow and when to reap, we would soon want bread."
Thomas Jefferson
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Thu Nov 01, 2007 1:32 am Post subject: |
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My current plan is to let it run for around 100 hours and see if it fixes itself. If not I will send it to VDC to see if they can fix it.
Chris.
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Chuchuf
Joined: 11 Mar 2006
Posts: 548
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| Posted: Thu Nov 01, 2007 3:37 am Post subject: |
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| tse wrote: | | macgyver655 wrote: | Hmmmm. Will it run with the vert deflection board pulled to see if you get a flat line?
I'm just thinking if it is electron flow from the gun then this might verify it. |
If it is somewhere else? I don't know if the Sencore will fix it.
Scott |
Charlie can.......I think it's kind of funny that you guys within your own company have this absolute tube guru and you don't use him.
Terry
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Tom.W
Joined: 09 Mar 2006
Posts: 6635
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nuttall_chris
Joined: 08 Mar 2006
Posts: 832
Location: Ottawa, Ontario, Canada
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| Posted: Fri Nov 16, 2007 7:52 pm Post subject: |
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Good news, I just got off the phone with Charlie at VDC, my tube is fixed 
As expected it was contamination of one of the guns.
I should have the tube back in about a week.
Chris.
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Chuchuf
Joined: 11 Mar 2006
Posts: 548
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| Posted: Mon Nov 19, 2007 1:25 pm Post subject: |
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| nuttall_chris wrote: | Good news, I just got off the phone with Charlie at VDC, my tube is fixed
As expected it was contamination of one of the guns.
I should have the tube back in about a week.
Chris. |
Good news.
I was talking to Charlie the other day about secondary emmisions and he said that the LUG's can do this more than standard tubes he feels because of the additional grid 3 in the gun assembly.
Terry
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