| Author |
Message |
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Sat Mar 31, 2012 11:00 pm Post subject: Strange Marquee problem. |
|
|
Here's one that Tim and I have never seen before, so Marquee owners take note:
I sold a Vision 1, 1 owner, low hours (2000) to a fellow in California. About 4 hours of viewing after he got it, the red tube started flickering. Occasionally it would go out completely, but usually it would simply jump in brightness by about 20%. I'd run it here 24 hours before sending it down, it was solid as a rock.
So I had him swap out CRT video neck boards. Problem stayed with the red. Swapped video cables on the VIM. Stayed with the red. Swapped G2 wires. Stayed with the red. Swapped wiring harness between CRT video amps, problem stayed with the red.
The changes were abrupt, instant on/off or brightness change. I figured either it was something to do with the chip on the backplane, or maybe something in the CLM. I'd tested some new boards for him, and he called me today. Apparently there was a tiny bit of corrosion on the red CRT tube pin(s). He reseated the neck board a 1/2 dozen times, and it's been solid.
He's been running it for 3 hours now, solid as a rock. Go figure. Tim and I have never run across this before.
|
|
| Back to top |
|
 |
draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
|
| Posted: Sun Apr 01, 2012 2:05 am Post subject: Re: Strange Marquee problem. |
|
|
| Curt Palme wrote: | | Apparently there was a tiny bit of corrosion on the red CRT tube pin(s). He reseated the neck board a 1/2 dozen times, and it's been solid.He's been running it for 3 hours now, solid as a rock. Go figure. Tim and I have never run across this before. |
I always put Caig on the CRt pins as well simplt because the card slides back on easilly. Now I know it's a good thing to do for other reasons.
I think those pins aren't plated at all are they? f they're just straight Brass then that's a good place for Oxidation.
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Sun Apr 01, 2012 3:11 am Post subject: |
|
|
Guys
I doubt the tube pins are brass; they bend too easily. I would like to know what they are made of. I had a customer attempt swapping neckboards to no avail, when I arrived for a look one of the filament pins was bent over flat. The tube ran again after straightening the pin.
.
|
|
| Back to top |
|
|
macgyver655
Joined: 22 Aug 2007
Posts: 8508
|
| Posted: Sun Apr 01, 2012 1:33 pm Post subject: |
|
|
| Tim in Phoenix wrote: | Guys
I doubt the tube pins are brass; they bend too easily. I would like to know what they are made of. I had a customer attempt swapping neckboards to no avail, when I arrived for a look one of the filament pins was bent over flat. The tube ran again after straightening the pin.
. |
I would guess aluminum or copper as both are great conductors and commonly used for electrical. Also both will oxidize. Snip one off and bad tube and check for color at the cut and check with magnet. Non-magnetic then check cut color. Silver for aluminum. Gold for copper.
|
|
| Back to top |
|
|
draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
|
| Posted: Sun Apr 01, 2012 4:34 pm Post subject: |
|
|
| macgyver655 wrote: | | I would guess aluminum or copper as both are great conductors and commonly used for electrical. Also both will oxidize. . |
your right, almost certainly Copper as it's a common material in high vacuum app's. The glass to metal transition is a tricky process as the 2 materials have radically different coefficent of thermal expansion.
|
|
| Back to top |
|
|
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Sun Apr 01, 2012 7:22 pm Post subject: |
|
|
|
Well, as it turns out, he called this morning, and the problem is back! It could still be a bad connection, but I'm going to swap the full set out for him. We've taken troubleshooting as far as we can go with this via email. I'm sure it's corrosion on a connector somewhere, as this set had no glycol leak, and it ran fine here.
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Sun Apr 01, 2012 11:59 pm Post subject: |
|
|
Guys
Well, I cut a tube pin off and the end pinched shut, very soft metal, could not see inside. I then bent one back-forth about fifteen times and it broke off, silver inside but this stuff must be some special alloy.........
.
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Mon Apr 02, 2012 2:57 am Post subject: |
|
|
Wow. This is what happens when a bright individual has Too Much Spare Time!
.
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Mon Apr 02, 2012 2:06 pm Post subject: |
|
|
Dang
Even Charles at VDC is unsure what the tube pin alloy is, and he has been in the CRT biz since the 60's!
.
|
|
| Back to top |
|
|
Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
|
| Posted: Mon Apr 02, 2012 2:17 pm Post subject: |
|
|
Apparently.... unobtanium! 
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Mon Apr 02, 2012 2:21 pm Post subject: |
|
|
| Curt Palme wrote: | | Apparently.... unobtanium! |
You can have all you want snipping pins off, we just can't tell you WTF that stuff is!
.
|
|
| Back to top |
|
|
macgyver655
Joined: 22 Aug 2007
Posts: 8508
|
| Posted: Mon Apr 02, 2012 2:23 pm Post subject: |
|
|
| Tim in Phoenix wrote: | | Curt Palme wrote: | | Apparently.... unobtanium! |
You can have all you want snipping pins off, we just can't tell you WTF that stuff is!
. |
Did you try a magnet on it?
|
|
| Back to top |
|
|
mc86
Joined: 20 Sep 2008
Posts: 767
Location: pittsburgh, pa
TV/Projector: ECP 4500 (Vidikron box), ECP4500+, wanting 07MS/07MTS, evaluating pc soft-blend
|
|
| Back to top |
|
|
Nashou66
Joined: 12 Jan 2007
Posts: 16171
Location: West Seneca NY
|
|
| Back to top |
|
|
macgyver655
Joined: 22 Aug 2007
Posts: 8508
|
| Posted: Mon Apr 02, 2012 3:51 pm Post subject: |
|
|
Very interesting metal for sure. But it is magnetic, being mostly iron and nickel. So if the crt pin is not magnetic it would rule it out. Nice find though. I enjoyed the read. But I don't know for sure so who knows......
http://www.hightempmetals.com/techdata/hitempKovardata.php 
|
|
| Back to top |
|
|
mc86
Joined: 20 Sep 2008
Posts: 767
Location: pittsburgh, pa
TV/Projector: ECP 4500 (Vidikron box), ECP4500+, wanting 07MS/07MTS, evaluating pc soft-blend
|
| Posted: Mon Apr 02, 2012 10:10 pm Post subject: |
|
|
Something akin to kovar is being used. Possibly the material has been demagnetized as well. The image shows is a chromium, titanium, iron material Toshiba sells they call PCV-K.
Matt
| Description: |
|
| Filesize: |
48.66 KB |
| Viewed: |
9214 Time(s) |
|
|
|
| Back to top |
|
|
macgyver655
Joined: 22 Aug 2007
Posts: 8508
|
| Posted: Mon Apr 02, 2012 11:04 pm Post subject: |
|
|
Interesting again. Titanium is not magnetic, but that's a very small amount. Chromium I'm not sure and probably more of an anti-corrosive, but the high iron content is magnetic. Of course you can't deny it says used for crt pins.
Not sure why you say demagnetized.
I like your findings though.
|
|
| Back to top |
|
|
macgyver655
Joined: 22 Aug 2007
Posts: 8508
|
| Posted: Mon Apr 02, 2012 11:10 pm Post subject: |
|
|
|
Of course this mixture kinda sounds like a type of stainless steel which would be non magnetic......but I think only if some nickel is added, which I dont see there.
|
|
| Back to top |
|
|
Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
|
| Posted: Tue Apr 03, 2012 5:10 pm Post subject: |
|
|
I found this
Kovar (trademark of Carpenter Technology Corporation) is a nickel-cobalt ferrous alloy designed to be compatible with the thermal expansion characteristics of borosilicate glass (~5×10-6 /K between 30 and 200°C, to ~10×10-6 /K at 800°C) in order to allow direct mechanical connections over a range of temperatures. It finds application in electroplated conductors entering glass envelopes of electronic parts such as vacuum tubes (valves), X-ray and microwave tubes and some lightbulbs.
The name Kovar is often used as a general term for Fe-Ni alloys with these particular thermal expansion properties. Note the related particular Fe-Ni alloy Invar which exhibits minimum thermal expansion.
My guess is that this is the alloy for tube pins.
.
|
|
| Back to top |
|
|
|
|
