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#1
03-24-2020, 09:31 PM
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Just repaired a Channel Master CM7000 digital to analog NTSC converter box
this CM7000 digital TV to analogue NTSC converter set top box quit working, and the red pilot light never changed color.
In the USA and that corona virus has us mostly stuck at home. So, looking for something to do, saw this dead converter box, and looked on-line for fixes others successfully did. Said that replacing all the leaded electrolytic caps on the "logic" board (vs the power supply board). The box came alive after I did the caps associated with switching DC-DC converter circuits (the ones that take 5V and make 3.3V and another to 1.2V, in the picture below marked "replaced but not necessary", was for me!). As I didn't have 33μF 35V caps on hand, I used 47μF at 50V caps. These caps filter out the switching waveform, so the caps being bigger is of little concern. Found this "answer" at another forum https://www.avsforum.com/forum/27-re...l#post59384596 from where I plagiarized the below picture.
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Last edited by wa2ise; 03-24-2020 at 09:36 PM. 
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#2
03-25-2020, 11:53 AM
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With the transition to ATSC 3 under way it seems a bit pointless fixing the older converter boxes that eventually won't have signals to tune...At this point I intend to run my boxes to fail.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
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#4
03-25-2020, 01:33 PM
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Most likely will be ATSC 3.0 to HDMI.
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Linear Mode
