Posted by
thomask.smith on
Aug 03, 2005; 9:53pm
URL: http://elecraft.85.s1.nabble.com/8T-8R-problems-tp380976.html
Hi everyone,
Since everything but the BFO was working I decided to finish wiring the
radio. Everything went down hill from there. At phase II all the control
functions worked perfectly but now the transmitter parts are in the
display flashes between the frequency, power output setting, and keyer
speed. In fact the radio is transmitting all the time. The finals get
warm plus the dummy load warms up. The voltage reading at the dummy load
is between 18 and 25 vdc.
I checked the 8T and 8R lines and 8T is 1.5 vdc and 8R is 7.1 vdc. The
manual isn't very clear on what they should be. I figured 8T would be
8vdc when transmitting and 8R would be 8vdc on receive. In the circuit
description is says that Q23 hold 8R at 0vdc on receive. As you can tell
my reading are way off.
Here are some more voltage reading that aren't right:
Chip U6 pin 24 0vdc
pin 25 5vdc
pin 27 0vdc ok
pin 28 4.2vdc
pin 36 4.5vdc
pin 39 1.0vdc
Q23 pin S 0vdc
pin G 1.5vdc
pin D 6.2vdc
Chip U11 pin 6 5.01vdc still low
pin 7 4.66vdc still low
I checked the whole radio again for bad solder joints and bridges -
still nothing found. I checked for the correct parts in their locations
- everything looks right.
Like I said at phase II the controls all worked as they should and the
display didn't jump around on it's own. The receiver peaked up fine on
40 meters. Because everything was working I figured it was save to
continue. The 8T and 8R lines were probably messed up the whole time but
since the transmitter wasn't wired the problem didn't show up.
Any ideas will be appreciated.
Thanks,
Tom K2 #5020
_______________________________________________
Elecraft mailing list
Post to:
[hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help:
http://mailman.qth.net/subscribers.htmElecraft web page:
http://www.elecraft.com