[ICOM] IC-2AT diode matrix question

[K6STU at aol.com]

hi jack. The battery is a 3.1vdc lithium battery. The battery is charged  via 
the +5vdc circuit through D118 in series with D119 to the plus side of the  
battery the neg side of the battery goes to ground. At the junction of the two  
diodes there is the battery lead that goes to the cpu  to Pin 65. that cpu  
was discussed earlier re the diode matrix connection. also  at the junction  of 
the two diodes there is a electrolytic cap the plus side connects to the  
junction and the minus side goes to ground.  The junction voltage is 3.1  voltsdc 
with power off and 4.5vdc with the power turned on. The part reference  
number is BT101 .  part number is BR2325-1HC. I don't know if they are  still 
available from Icom. Hopefully the battery has another number on it that  you can 
crossreference.
Gool Luck.
Mike
 
 
 
 
 
 
 

c hi jackIn a message dated 3/21/2005 7:32:21 A.M. Pacific Standard Time,  
vhfplus at bmg50.com writes:

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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