[ICOM] IC-2AT diode matrix question

Jack/AE7DX vhfplus at bmg50.com
Mon Mar 21 10:31:29 EST 2005


K6STU at aol.com wrote:

> 
>hi jack you are correct. there are only 4 diodes in the matrix. there are 4  
>horizontal and 4 vertical lines that make up the matrix. the 4 vertical lines  
>are from left to right are R10, R11,  R12, and R13. the 4 horizontal lines  
>are from top to bottom R23, R22, R21 and R20.
>it looks like a larger version of tick tack toe diagram.D407 consists of  two 
>diodes. Diode one The cathode/bar connects to line R23 and the Anode  
>connects to R12. The second diode the Anode connects to R12 and the cathode/bar  
>connects to R22.      D402 the bar connects to R21 and  the anode connects to R11. 
>D403 the bar connects to R20 and the anode connects  to R12.
>     The diode matrix connects to the left side of IC  401 which is located 
>above the speaker on the logic board. the pin out on on IC  401 is from top to 
>bottom 65 through 80. 66/R10, 67/R11, 68/R12, 69/R13, 70/R20,  71/R21, 72/R22, 
>73/R23. 
> When you have the unit open with the speaker half on the left and the  the 
>other half that has the  controls on the top look at he  bottom left you will 
>see the memory back up  battery. Just to the  lower left of this battery is the 
>CPU reset switch. With the power switch on  press the reset switch and this 
>will reset the CPU.
>If this doesn't fix it I  don't know what to tell you.
>Good Luck.
>Mike, K6STU
>  
>
Mike:

The CPU reset did, in fact , work. I was able to give my son his first 
QSO on 146.52 simplex. Unfortunately when I turned the rig off and then 
back on later the '02AT was not functioning properly (same symptoms as 
before the CPU reset). I have to assume that the memory backup battery 
is not doing it's job and will have to be replaced.

Oh, well, at least I'm getting nearer the end of the saga. Thanks very 
much for your assistance!

73,

Jack, AE7DX


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