[Elecraft] KAT100 signal question

[Jack Brindle]

On Jul 23, 2005, at 11:42 AM, BobConvers at aol.com wrote:
> Thanks, Don.   Actually, I get NO action from ANY relay, although  
> the LEDs
> are switching correctly.   I tried to check the signal RYDATA (as  
> best I could
> with no scope, only DMM) and it is an absolutely constant level.    
> The front
> panel signal FPDATA jumps around in value as the signals come  
> through to
> activate the LEDs, but RYDATA is dead still.


It is not surprising that you are seeing the FP serial bus so active  
- it is periodically being refreshed. Relays are another matter. The  
RY serial bus is rarely (in processing terms) used. It is, in fact,  
used only when a relay state needs to be changed. If that doesn't  
happen, you won't see any toggles on the RYCK, RYLOAD or RYDATA lines.

> There is 12 v on the the hot side of
> the relays and 5 volts on pins 2 of U2, U3, and U4.   With power  
> removed,
> RYDATA measures over 5 megs to ground.   Any other suggestions?

None of these measurements really say anything. What is the level of  
RYDATA, RYLOAD and RYCK at both the MCU and U2, U3 and U4?

Have the relays ever worked, or is this a new unit? You might want to  
check the solder joints at pins 15, 16 and 17 of the MCU, as well as  
those at pin 3 of U2, and 12 and 13 of U2, U3 and U4. Lastly, cycle  
through the K2 menu's C and L settings to check for any relay action.  
It is quite possible that the KAT100 is simply not commanding the  
relays to change - the question in that case is why not?


- Jack Brindle, W6FB
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