Restoration of a digital to analog converter box - Printable Version

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+--- Thread: Restoration of a digital to analog converter box (/showthread.php?tid=21092)

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Restoration of a digital to analog converter box - wa2ise - 03-18-2020

This is about fixing a bad set top converter box, for your Philco TV set. 

I had a dead Channel Master CM7000 HDTV to NTSC analog converter box.  Its red pilot light, usually an indicator that lights during a boot-up after plugging this box to the powerline, never went to green or orange (indicating it is ready for the user)

As is usual with electronics made recently, it had bad leaded electrolytic caps.  Googled "dead CM7000" and found this thread: https://www.avsforum.com/forum/27-replaytv-showstopper-pvrs/1322061-dead-cm-7000-a-4.html#post59384596

I already tested the power supply by using it to power the "logic" board in another CM7000, and it worked.  So the problem is in the dead box's "logic" board.  I got joy   after changing caps E5 and E6 (as marked on the circuit board).  These caps are filters on switching DC-DC voltage converters, going from 5V (or is it 12V) to 3.3V and a second circuit 1.2V.

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RE: Restoration of a digital to analog converter box - morzh - 03-18-2020

Who made the caps and what kind?

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RE: Restoration of a digital to analog converter box - wa2ise - 03-19-2020

I tossed them in the trash, I took a look to see if I could find them, but couldn't find them.  They were some no-name brand of aluminum leaded electrolytic cap made of Chineseium...

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