You are right!! After U6 removed.... RP4 pin 5 and 6 are now at 81k
ohm!!
U6 must be replaced
Thanks for your help..... But one question remains..... What did
happen to U6 ??
Jean-François Ménard
Le 08-09-19 à 09:52, Don Wilhelm <[EMAIL PROTECTED]> a écrit :
Jean-Francois,
Sounds like you are homing in on the problem. Try removing the
microprocessor and measuring the resistance between RP4 pins 5 and
6. If it is normal (81K), then you have a bad microprocessor input
at pin 30. If so, replacement of U6 is the only solution I know
about.
73,
Don W3FPR
Jean-François Ménard wrote:
I also found another thing.....
Resistance check of Pin 7 and 8 of RP4 on the control board give me
81K ohm, but PIN 5 and 6 give me 19K ohm... should be 81K ohm too !!!
Le 08-09-19 à 09:29, Jean-François Ménard a écrit :
It seems that a resistence check on the control board give me a
hint..... U6 PIN 29 are inside spec, but PIN 30 give me only 16K
ohm and should be higher... around 80K ohm to 90k
The key jack seems to be good, R1 and R2 are OK.
Re-insert controler on RF board, nothing change
Le 08-09-19 à 08:11, Don Wilhelm a écrit :
Jean-Francois,
It certainly could be a faulty key jack, but it could be a
microprocessor problem too.
Turn the power down to zero for further testing.
Then check the voltage at the end of R1 and R2 near the key jack
- they are easy to reach if you remove the left side panel. The
voltage should be near 5 volts if there is nothing pulling those
inputs down.
Remember that the DOT line and the PTT line are one and the same
on the K2, so if that line is low the problem nay be in the key
jack or on the Front Panel board.
Should you find either the DOT or DASH lines near zero volts,
turn power off and make resistance checks to find out if there is
a short (maybe a solder bridge that has been dormant for a long
time). Those signal lines run direct to the microprocessor, so
there is only the jacks, PC traces, and the microprocessor
involved.
73,
Don W3FPR
Jean-François Ménard wrote:
It seems that something let my K2 stuck in TX mode. I removed
all module and put appropriate jumpers (unmod kit). Still in TX
when powered ON. I checked this using my DL2 dummy load with my
multimeter.... I always have output power !!
Could it be a defective KEY jack that is jammed? I have nothing
plugged......
Le 08-09-18 à 23:33, Don Wilhelm a écrit :
Jean,
This is strange - the second case of similar behavior reported
on the reflector today. Could it be a case of the 'phase of
the moon'?
When the K2 is in transmit state, the behavior will be as you
describe - no buttons operate but the K2 displays the frequency.
Check to see if your K2 is somehow stuck in transmit. The
easiest way is to check the state of the 8R and 8T voltages.
You can checkby measuring the DC voltage at the anodes of D6
and D7. During receive, the voltage at D6 anode should be
about 8 volts and the voltage at D7 should be near zero volts.
If the K2 is 'stuck in transmit', those voltages will be
reversed.
If your K2 is indeed 'stuck in transmit', try removing the key
plug and the microphone - if something external is creating
that transmit condition, it should be OK with those cables
unplugged.
73,
Don W3FPR
Jean-François Ménard wrote:
Hi everybody,
I have my first major trouble since my building experience
back in 2004. Now, everytime i power up my K2, I can see
ELECRAFT and then the frequency..... but everything is frozen
after...... still get the frequency displayed, but no button,
no function work. I also tried to reset the K2 to the factory
default by holding 4-5-6 buttons..... Got the 201 message then
back to the ELECRAFT and the frequency..... but still
frozen !!!!
Is it possible the the control board PIC got a static
discharge or something like this !?!?!?!
============================
De Jean-François Ménard / VA2SS
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