Bob,
I would think Q3 is OK since it simply acts as a switch - it does not
produce any voltage. The MCU (U1) pin 39 is the source for voltage on the
drain of Q3, and a high level of somewhere near 5 volts is to be expected.
Look somewhere else for the problem. It is difficult to see directly
Q3 is probably not your problem. It is an open-drain switch that
inverts the 8R signal, conditioning it for the microcontroller. It
appears that the MCU provides the pullup for the signal through the
internal pullup on PB6. 4.99 volts is about right for this signal.
Just what is the relay
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
returns to work on Monday.
73,
Don W3FPR
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of [EMAIL PROTECTED]
Sent: Saturday, July 23, 2005 2:43 PM
To: [EMAIL PROTECTED]; elecraft@mailman.qth.net
Subject: Re: [Elecraft] KAT100 signal question
Thanks, Don
On Jul 23, 2005, at 11:42 AM, [EMAIL PROTECTED] 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
Jack, as I mentioned to Don, I get NO relay action on ANY relay, as I switch
from ANT1 to ANT2 and /or adjust POWER on the K2/KPA100. The KAT100 front
panel LEDs light up correctly.
I was almost certain that before when I checked I saw no change on RYDATA,
but I checked again and found that
Bob,
If you can see a drop on the RYDATA voltage when you switch from ANT1 to
ANT2, you can chase that bit through the first shift resister - look for a
similar drop at U2 pin 18 (and U3 pin 3). It will only drop for the change
from ANT1 to ANT2 (and not the other way 'round), and you get only
This is a new KAT100, just completed and under test. I have never observed
ANY relay action.
RYLOAD remains at 2.25v and bounces a bit each time I adjust, say, ANT1 to
ANT2.
RYCK appears steady at about zero; and 5Megs to ground with no power.
U3-3 and U4-4 are always zero, also 5Megs to
See notes and questions inside your comments...
On Jul 23, 2005, at 1:10 PM, [EMAIL PROTECTED] wrote:
This is a new KAT100, just completed and under test. I have never
observed ANY relay action.
What makes you think the box is running at all? What is being
displayed on the front panel,
To put it another way, what _is_ working?
Sorry, I had not repeated information from an earlier post: I have proceded
in constructing the KAT100 as far as the step of connecting the KAT100 to the
K2/KPA100, on the K2 panel switching back and forth between ANT1 and ANT2,
looking for proper
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