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Discussion Starter · #1 ·
Hi,

I have couple of questions regarding maintenance of Neck Boards for M8000. My 8000 developed very faint blue streaking, mostly visible on darker and bluish backgrounds, streak being lighter when object to it's right is lighter, and darker (sort of almost like a shadow), when it is darker. It DOES NOT happen with white objects on black background. It IS present (as far as I can determine) on internal patterns too, so it is NOT source related. It is not visible on most material, but of course I KNOW it is there, and it drives me crazy!... I looked trough most of the archives for possible cause and solution, and found, that most likely it is related to Blue CRT Neck Board. (I will try to swap it with one of the other two to be sure, but it's not easy, since PJ is hanging on the ceiling).

Now, I was getting ready to implement some of maintenance tips from Marquee Maintenance Archive anyway, so it may be good opportunity.

Here are my question:

Tread mentions replacing CLC409 IC with CLC449. Is it still valid? Down the line, Curt talks about LMH6705 which was not available at the time, as another possibility. I checked, and LMH6705 is currently available. Is it better (the best) choice? Are there some never IC's available?

Also, what's the best source for getting Video Neck Board? I want to work on the spare and than on the other two, so I can enjoy PJ in the mean time... Of course...

It is still awesome system!...

Any other suggestions?

All your help will be greatly appreciated,


Kris
 

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You should replace the CLC-409 with the later CLC-449 chip, which is what was done by the factory. Unfortunately, the CLC-449 is pretty difficult to find in small quantities.


Although the LMH6705 was claimed to be the replacement for the CLC-449 by National, my recollection was that Mike Parker had tried one at the time and said it wouldn't work as a "drop in" replacement. I've never tried one myself, so I don't know, so the best thing to do would be to ask Mike.
 

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Discussion Starter · #3 ·
Thanks,

I will try to contact Curt in near future, just didn't want to bother him unnecessary, and I thought the info my benefit others as well. The data in the Maintenance Archive is getting old with respect to model numbers, availability etc... I think that update would be valuable,


Regards,


Kris
 

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There are some Marquee input boards on Ebay. just buy one of those. Should be quite cheap. darned cheap.


Thre is a manufacturing date stamped on the back of every input board, have the seller get that info to you to determine if the input board is new enough to be using the 449.
 

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Discussion Starter · #5 ·
Thanks guys for your suggestions, as always it's good idea to ask before you do... Specially here...


Regards,


Kris
 

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I recently suffered the same problem and was able to reapair it myself. Although it is a good idea to replace the 409's with 449's, the cause of your streaking is most likely Q13 on the neckboard (Motorola MRF549 transistor). Curt sells non working boards on FleaBay for 10ea. and if my memory serves me correctly each board has two of those transistors on it.


If you go this route, which is most likely the cheapest, be aware that Q13 on the board you buy from Curt could have the same problem. I took Q13 from his board and put it in mine and still had the same problem, very discouraging... then I decided for kicks and grins to try the other MRF549 on Curts board and whalla, it worked! Streak free nirvana!
 

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Discussion Starter · #7 ·
Thanks! Curt actually suggested this same! I bought 3 Boards from Him (awaiting delivery), so I should have plenty to experiment (and replace others if necessary in the future).

As always, people are unbelievably helpful here!

Thanks again,

Kris
 
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