Audio Systems: TV remote not working, philips tv, ir signal

Question
I have a Philips TV 27PT643R37A.  My TV stopped responding to my universal(RCA) remote.  The TV works fine when you push the on/off button on the front of the TV.  The channel and volume buttons on top also work fine.  The picture is as good as new.  Normally, when the remote stops working, I'll reprogram it.  The TV won't respond.  I have another identical remote that presents the same problem.  I even tried to use the original Philips remote that came with the TV, just to have the TV not respond.  I made sure I had good batteries in each remote as I tested them.  I verified the universal remote was good by the fact that it would still operate my VCR.  I replaced the IR receiver and the problem didn't go away.  A friend told me it is often a chip on the mother board that goes out, a chip that is used to process the IR signal.  I have no idea what this looks like or where it is located.  If I knew which part is was, I could order a new one and replace it.  Can you help me?

Answer
The IR receiver replacement should have remedied this problem.  Are you certain it was the correct unit and was it installed correctly?  You should check that out very carefully making certain the IR eye is not covered or blocked by the housing.

You will need the schematic and parts list for other parts of the set OR have it looked at by a Philips trained tech.  

The comment about a chip on the main board needing replaced is speculation; it may or may not be due to that malfunction.  

Also, you should reset the tv by unplugging it for a full 3 or 4 hours.