Scott,
Your power supply and internal power connections are OK.
Do not be too hasty to believe U3 is faulty.
Did you check the switch or jumper on the top of the control board (just
to the right of center - next to P5)? Having the switch or jumper in
the EXT position rather than the INT would cause exactly the symptoms
you describe.
If the switch (or jumper) is in the correct position, then if the path
through the PC traces and resistors Control Board R9 and R10 are
correct, you should read 2.57 volts on U3 pin 5 (plus or minus a bit).
If you have 2.57 volts on U3 pin 5, then pins 6 and 7 will also be at
2.57 volts if U3 is working correctly, and you will also have 2.57 volts
at U6 pin 5. OTOH, if U3 pin 5 is way off 2.57 volts, then you have a
problem with either the PC traces or R9 or R10.
73,
Don W3FPR
Scott McDowell wrote:
Don W3FPR
At the cathode of D-12 in receive mode I get 13.17 volts.
At the cathode of D-12 in tune mode at 10 watts I get 12.5 volts.
The K2 display shows .260 ma in receive mode
and 2.10 amps in transmit ( tune mode).
I don't get any voltages fromt he display because
that part doesn't work.
R9 and R10 both check ok.
To me, this all seems inline with what you said they should
be. Am I all wet?
This leave U3B, so I think I will order another and see
what happens then.
Thanks for your help
73
Scott
N5SM
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