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HCN4727 Blue CRT issue    
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rayodunne



Joined: 29 Dec 2008
Posts: 6

PostPosted: Mon Dec 29, 2008 7:35 pm    Post subject: HCN4727 Blue CRT issue Reply with quote

I got this set with a no power on issue and replaced the convergence board with the STK's on it. The TV then fired right up and convergence was perfect. I did notice however that when I put it on a tv channel that the screen had an orange hue down both sides of the screen.
I went into convergence menu and discovered that when I muted the red and green the blue was barely visible in the center of the screen and not visible in the orange hue section of the screen.
I checked the CRT PCB for any bad solders and cracked traces and found none. I'm puzzled as to why only the blue CRT would be giving me issues.
I found no leaking coolant which these sets can leak.
Any ideas guys?
Thanks!
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Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Tue Dec 30, 2008 11:15 am    Post subject: Reply with quote

You are describing a contaminated fluid condition. Remove the screen (or in your case it is probably easier to remove the upper back (the part with the mirror attached))and look directly into the blue CRT while the set is on. You can compare the pictures of the green and red CRT's for a reference. If the CRT has contaminated fluid, it will become obvious when you look directly into the CRT. It is possible that the green CRT has a level of contamination also but the red CRT will not have any at all. The reason for this is the light wavelength prevents the algea from growing in the red.

If you do indeed have contaminated fluid the CRT comes with the fluid chamber included and the fluid and seals are not available seperately.

Hope this helps

Jesse
rayodunne



Joined: 29 Dec 2008
Posts: 6

PostPosted: Fri Jan 02, 2009 9:50 am    Post subject: Reply with quote

Thanks for your reply. Is there any way to test the tube so I am 100% sure before ordering a new one. I just don't want to keep throwing parts at this TV.
kuhurdler



Joined: 28 Dec 2006
Posts: 2879
Location: Overland Park, KS

PostPosted: Fri Jan 02, 2009 10:19 am    Post subject: Reply with quote

Jesse Mack wrote:
If the CRT has contaminated fluid, it will become obvious when you look directly into the CRT.
rayodunne



Joined: 29 Dec 2008
Posts: 6

PostPosted: Mon Jan 05, 2009 10:13 am    Post subject: Reply with quote

Ok I checked out the tubes and indeed the blue tube is very contaminated and the green is slightly contaminated. Is it possible to clean out the tube rather than buy a new one?
I have found CRT Coolant online so it is available.
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Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Mon Jan 05, 2009 1:01 pm    Post subject: Reply with quote

Coolant is available for the older philips/magnavox units that make available the seals.

To answer your question: No, there are no parts available from any source to repair these CRTs. Go here: http://www.andrewselectronics.com the price for the assy is $147.62 + shipping or from here: http://www.searspartsdirect.com/partsdirect/index.action for a price of $147.91 using either the model number or part number BP91-00817W

The shipping is MUCH lower at Sears Parts Direct

Believe me that considering the price of the tube it is much easier to simply replace the tube.

Hope this helps

Jesse
rayodunne



Joined: 29 Dec 2008
Posts: 6

PostPosted: Mon Jan 05, 2009 1:10 pm    Post subject: Reply with quote

Thanks for your help Jesse.
I took out one tube last night in about 4 mins and found the opening for draining and filling. I also found a site with info on replacing the coolant and none of the guys bought new seals and none of them experienced leaks that they spoke of. I just simply can't afford to splurge $147 plus shipping on a new tube if I can fix it with 2 bottles of coolant costing $10 each.
Jesse Mack



Joined: 22 May 2008
Posts: 600
Location: The Last Frontier

PostPosted: Mon Jan 05, 2009 1:20 pm    Post subject: Reply with quote

You will be very disappointed doing this in this way. The coolant is contaminated and you will not be able to remove the contamination without disassembling the CRT assy. You have to clean the parabolic lense and the crt face with denatured alcholol (sp) to kill the algea or the problem will return in a short time. Also, the contamination is THICK. Kind of like goey slime. Trust me, this is NOT the way to go.

Besides, you are going to find out that when you reinstall the CRT you are going to have to reconverge the set and if you disassemble the tube the convergence is going to be a major convergence.

I know that money is tight but it seems to me that throwing good money after bad is not a wise thing to do.

Hope this helps.

Jesse
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