[Yaesu] FT-990 problems

kz8e at wt.net kz8e at wt.net
Wed Jun 5 10:21:41 EDT 2013


After a two year medical sabbatical from radio, job, and life in general I returned home to find my FT-990 DOA.
 
I have resolved the issue down to Q5004 on the Control Unit.  This is a Mitsubishi M37700M4-117FP microcontroller with built in programmable ROM.
 
My manual calls it Yaesu part number G1091180.  I bought the radio used a long time ago and knew that it was upgraded to Rom Version 1.3 or later because the CAT communications worked.  I also knew that this part had been changed before in my radio because there was flux on the PCB around the pins of this component.  Obvious sign of rework.
 
I wanted to be sure that the part number of the part listed in my manual was going to be the Version 1.3 or later that fixed the CAT comm problem.  Checking with Yaesu, who were most helpful in spite of the age of the radio, I discovered that the Yeasu p/n G1091180 is the version 1.2 ROM but that p/n G1091594 or p/n G1091595 would have version 1.3 of the code that I needed.
 
Problem is those parts are out of stock but they do have the p/n G1091180 which will get my radio working but won't support the CAT interface.  Ugh.
 
Question is:  Does anyone know of a secret stash of ROM ver 1.3 parts (used or new) or am I going to be forced to get what part I can to just get the radio working?
 
Earl 
N8SS


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