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mmwalcz
Joined: 30 May 2011
Posts: 4
Location: Poland
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| Posted: Mon May 30, 2011 10:06 pm Post subject: EM 8500 -green tube not work |
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Hi,
some time during normal operation, the green tube starts to blink , now it is not lit at all. Other tubes are working properly.
Where to find the possible causes?
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Mon May 30, 2011 10:30 pm Post subject: |
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Hello
New guy? Welcome aboard!
Marquee 8500? Same problem with internal patterns? Try reseating the small coax cable from the VIM to the green neckboard, there could be a smidge of tarnish on the plugs or sockets. Try swapping the red VIM cable for green, maybe the VIM is beginning to fail. Try measuring G2 at the tip of neckboard R76, should be 500 to 600 volts dc. Try also swapping the green neckboard with red.
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Tue May 31, 2011 4:18 am Post subject: |
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I had a similar problem, I found an intermittent problem with the C3 cap on the VNB, after changing that the problem is totally gone. Check for it's resistance, it should be measured to open.
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mmwalcz
Joined: 30 May 2011
Posts: 4
Location: Poland
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| Posted: Sun Jun 05, 2011 9:50 pm Post subject: |
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Yes, Marquee 8500. Same problem with internal patterns. I tried reseating the small coax cable from the VIM to the green neckboard -no tarnish, no effect. I swapped the red VIM cable for green - green and red tube worked. Switching back to cable - green tube for a short time is running normally, but after a minute of blinks and finally off again. Unfortunately, I do not know exactly where to find these points for voltage measurement (G2 at the tip of neckboard R76). Where is green and red neckboard?
Last edited by mmwalcz on Sun Jun 05, 2011 9:55 pm; edited 1 time in total
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mmwalcz
Joined: 30 May 2011
Posts: 4
Location: Poland
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| Posted: Sun Jun 05, 2011 9:54 pm Post subject: |
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| gjaky wrote: | | I had a similar problem, I found an intermittent problem with the C3 cap on the VNB, after changing that the problem is totally gone. Check for it's resistance, it should be measured to open. |
Unfortunately I do not know where is the C3 cap on the VNB. Please some more guidance...
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gjaky
Joined: 05 Jun 2010
Posts: 2802
Location: Budapest, Hungary
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| Posted: Sun Jun 05, 2011 10:07 pm Post subject: |
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Well, if you are not familiar with delicate soldering techniques and electronics I DON'T suggest to try to repair for yourself. However, if I remeber correctly the C3 is somewhere in the upper area (opposite of the sonnector side) of VNB
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draganm
Joined: 08 Mar 2006
Posts: 8990
Location: Colorado
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| Posted: Mon Jun 06, 2011 2:33 am Post subject: |
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| mmwalcz wrote: | | Yes, Marquee 8500. Same problem with internal patterns. I tried reseating the small coax cable from the VIM to the green neckboard -no tarnish, no effect. I swapped the red VIM cable for green - green and red tube worked. Switching back to cable - green tube for a short time is running normally, but after a minute of blinks and finally off again. |
switch them and see if it keeps running.
did you put some of this on the connector? the little brush can reach inside the co-axial socket and also on the male pin.
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mmwalcz
Joined: 30 May 2011
Posts: 4
Location: Poland
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| Posted: Mon Jun 06, 2011 9:06 pm Post subject: |
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I cleared the merger pursuant to the instructions and now everything is fine! Green tube working again... Thanks!
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