[QuadList] Problem AVR 3

David Crosthwait david at dcvideo.com
Wed Apr 6 12:14:40 CDT 2011


Lee,

With color bars as input, what is happening E-E? On the vector scope, are the vectors as sharp dots, or are they indeed passing through low-band filtering?

The fact that the machine appears to be stuck in low band may be pointing to a main bay power supply problems. Check for both voltages and for a hum free scope display. It is possible that one card is dragging down the whole bay, especially logic (which may be why the machine is full time in low band). 

Best Regards,

David Crosthwait
DC Video
Archived Media Transfer and Re-mastering Services

Offices located at:
177 West Magnolia Blvd.
Burbank, CA. 91502
818-563-1073
818-563-1177 (fax)
818-285-9942 (cell)

DAVID at DCVIDEO.COM
WWW.DCVIDEO.COM




On Apr 6, 2011, at 8:48 AM, lee williams wrote:

> Have a interesting problem with one of my AVR 3's.
>  
> I have consistently low RF readings at the tracking meeter and can't get the RF up to normal levels.
>  
>  
> Here is what I see.
>  
> A known good hi band tape that will display RF between 80-85 in any other machine will only display 10-15. 
>  
> Low Band light always on.
>  
> Auto Chroma won't respond on #4 card.
>  
> Looking at the Demod in the wave form monitor, the sync level looks 10 IRE low.
>  
>  
> Here is what  I have tried.  (all swap outs are with known working machines)
>  
> Swapped out pre amp behind head.
> Changed out MDA  (it was bad with other issues)
> Swapped out every card in the lower frames.
> Changed out power supply frame.  (it had cap problems with other issues)
>  
>  
> This one has me good.
> Nothing visible as far as the wiring harness.
> I am kind of running out of things to swap/look at.
>  
> Has anybody else ever experienced this one?
>  
> Also,
> Were will the get together be at NAB?
> Plan on being there for Monday and Tuesday.
>  
> Thanks
> Lee
>  
>  
>  
>  
>  
> 
>  
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