The Electronics Universe

Electronics Forum => Test Equipment => Topic started by: The Radio Shop on November 17, 2014, 08:16:28 PM

Title: Sencore CB42 repair thread
Post by: The Radio Shop on November 17, 2014, 08:16:28 PM

This will be an upcoming repair thread on this unit

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 17, 2014, 08:45:03 PM

Well there is a signal under all that noise.
Sitting at 26.919 MHZ

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 18, 2014, 05:09:05 PM

10 volt to IF board

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 27, 2014, 08:10:29 AM

RF/IF 5 volt regulators

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 27, 2014, 10:29:49 AM

While testing the counter board (H) I found that the 10 MHz clock was not present.
I did verify that the crystal works by inserting it on my crystal tester.
Now to find what component in the osc circuit is not working.

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 27, 2014, 03:08:22 PM

Closer, here I am generating a frequency on channel 20. But the display is not showing the frequency. But at least all 7 digits are running. And when changing channels what there changes on the display.

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 28, 2014, 03:31:47 PM

Scope screen shot of IC211 pin 2

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 28, 2014, 03:32:44 PM

bigger

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on November 28, 2014, 03:50:44 PM

IC205 pin12

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on December 07, 2014, 09:20:02 AM

Here is a block diagram

Title: Re: Sencore CB42 repair thread
Post by: The Radio Shop on December 07, 2014, 09:20:45 AM

try to upload a bigger image