[ICOM] Still Need Help IC-746

[Matthew Jenkins]

I talked to the origional owner and he said that the radio worked fine after
it's MARS mod years ago, so it was probably done correctly. He said that the
problems started when he took the radio out of storage (in it's box in a
closet in the house in the Tenn. Mountains) and hooked it up to use it. He
noticed that one and only one of the memories was missing. Everything else
was fine except for the one missing memory. He tried to re-enter the memory
information into the radio's memory bank, but the radio would not accept it.
He called ICOM Tech Support. They told him it was probably a glitch and that
he should probably re-set the CPU and that would most likely cure the
problem. So he did and radio lost all memories and other user setttings.
Now, I have tested this and I can enter memories into the memory bank and
retrieve them but when I turn the radio off, it looses everything and starts
over like it is a new radio or has just had the CPU re-set.
Now, the other problem was unknown to the previous owner so he could not
comment on it. The problem is that when the button for 24 mhz band is
pressed, the radio will display 24.950.00 mhz. Now, the tuner gives an error
beep if you press it and the ANT 1 and ANT 2 icons are not selectable or
visable (same as when you are in the 2m band). If you try to TX, you get
nothing and RX is dead. If you press the DUP button the freuency shown in
the TX window is 424.95000 mhz! If I rotate the VFO counterclockwise, the
display jumps to 174.000.00 mhz! If I rotate the VFO knob clockwise (from
the starting point of 24.950.00 mhz) the radio will jump to 0.030.00 mhx!
The ANT 1, ANT 2 and TUNER selections now work normally. I can dial up to
24.950.00 mhz from 15 meters or somewhere else and the radio works as it
should. I can use the keypad for direct frequency entry and that works as it
should. I can use the 24 key which is also the #8 key to enter frequencys
and it also works as it should. This sounds like a diode band selection
matrix problem, but everything seems to be in order there....

I was led to belive by the previous owner that the memory back-up battery
was bad or maybe a capacitor that was supposed to perform a simular function
had gone bad, but after studying the schemeatics and talking to ICOM, there
are no such caps or batteries in the radio.
I had belived that the radio was just resetting it's CPU on every power up,
but I have now developed another theory....
I think the radio has a no-violatol eeprom or other type of memory chip
seperate from the CPU someowhere and it is either loseing it's data on power
down or it is not accepting any data from the CPU. When the radio powers up,
the CPU looks to the EEPROM to see where it was last time it was on and
whatever user settings are supposed to be, and it finds nothing, so it loads
the defaults. Any thoughts?
Now, about the 12m band thinking it is on 424mhz.... I am a bit stumped on
that one. The band/country selection matrix appears to be ok as best I can
tell, so if it is, then it maybe a firmware issue.. It may be a firmware
issue anyway....
HELP!!!!!
Any thoughts????