Populating missing dates in postgresql data

Alright everyone, this is a doozy of a problem. I am new to Postgres so I appreciate patience/understanding. I have a database of hardware objects, each of which has several different "channels". Once per day, these channels are supposed to check in with a central server, generating an event log table (TABLE A) like the following:

object_id channel check-in date
****************************************
990 1 2014-12-01
990 1 2014-12-02
990 2 2014-12-01
990 2 2014-12-02
286 2 2014-12-01
286 2 2014-12-02
286 5 2014-12-01
286 5 2014-12-02
4507 1 2014-12-01
4507 1 2014-12-02
4507 2 2014-12-01
4507 2 2014-12-02

And so on. Occasionally, communications will break down to the hardware, such that no reporting occurs. For example, let's say that object 286 loses communications on 12/1/2014. Then the table might look like:

object_id channel check-in date
****************************************
990 1 2014-12-01
990 1 2014-12-02
990 2 2014-12-01
990 2 2014-12-02

286 2 2014-12-02

286 5 2014-12-02
4507 1 2014-12-01
4507 1 2014-12-02
4507 2 2014-12-01
4507 2 2014-12-02

Or let's say that for some reason, just channel 2 loses reporting for a day. Then we would have:

object_id channel check-in date
****************************************
990 1 2014-12-01
990 1 2014-12-02
990 2 2014-12-01
990 2 2014-12-02

286 2 2014-12-02
286 5 2014-12-01
286 5 2014-12-02
4507 1 2014-12-01
4507 1 2014-12-02
4507 2 2014-12-01
4507 2 2014-12-02

I have a second table (TABLE B) with all of the object_ids and channels that are supposed to be reporting in each day. For cases where a certain channel does not check in, I want to add a column that indicates the comm failure. So, for the example where all channels on object 286 do not check in, I would like to get is something like this:

object_id channel check-in date comm failure
**********************************************************
990 1 2014-12-01 No
990 1 2014-12-02 No
990 2 2014-12-01 No
990 2 2014-12-02 No
286 2 2014-12-01 Yes
286 2 2014-12-02 No
286 5 2014-12-01 Yes
286 5 2014-12-02 No
4507 1 2014-12-01 No
4507 1 2014-12-02 No
4507 2 2014-12-01 No
4507 2 2014-12-02 No

I have been racking my mind for the better part of a day on how to do this. The thing is that I can do a right join of TABLE B on TABLE A, and this will populate the missing object ids and channels. However, this only works for a single day, and it gives me something like:

object_id channel check-in date comm failure
**********************************************************
990 1 2014-12-01 No
990 1 2014-12-02 No
990 2 2014-12-01 No
990 2 2014-12-02 No
286 2 Yes
286 2 2014-12-02 No
286 5 Yes
286 5 2014-12-02 No
4507 1 2014-12-01 No
4507 1 2014-12-02 No
4507 2 2014-12-01 No
4507 2 2014-12-02 No

I need to do a count of comm failures by day, so I need to populate the check-in date field. Please help!

Best Regards,
Steve

*************************************************
Steven Lavrenz, MS, EIT
Doctoral Research Fellow, Ph.D. Candidate
Purdue University | Transportation Engineering
Hampton Hall of Civil Engineering, Room 1122
550 Stadium Mall Drive
West Lafayette, IN 47907
765-775-6423
slavrenz(at)purdue(dot)edu<https://exchange.purdue.edu/owa/redir.aspx?C=1KvRJRKXRUmCQXrzhc8xxDD2sumyJNIICxsOWx4t9faOapFqc_-gBVMV21AYScHluQX0uMJmOYA.&URL=mailto%3aslavrenz%40purdue.edu>