Page 269
E~=**---*****dl
(
)
If there
is
no indication on your voltmeter, proceed to
"Carrier
GenIXtal Filter Circuit Board," Page 306. Use
the RF detector to check for RF voltages at
B
of
0602, C of 0604, T601 (the terminal going to
connector #22
is
grounded), and C of Q611. The
indications at the three terminals of
T601 will bevery
low.
NOTE: DC voltage readings should only be made on board
E
when no RF voltage
is
present.
(
Disconnect the gray wire from pin 6 or board
E.
TRANSMITTER
IF
(
)
Connect the gray wire of the RF detector to pin 24 of
board C.
( )
If there
is
no indication on your voltmeter, proceed to
"Transmitter IF Circuit Board," Page 298. Check for
RF voltages on the collectors of 0305, 0304, the
emitter of 0301 and pin 4 of
IC301 (very low at pin
41.
(
)
Disconnect
the
gray wire from pin 24 of board C.
DRIVER
( )
Switch your voltmeter to a 10V or 15V range
(
)
Connect the gray wire of
the
RF detector to the anode
(unhanded)
end of diode Dm4 on the driver circuit
board.
(
)
If there
is
no indication on your voltmeter, proceed to
"Driver Circuit Board," on Page
3M).
Use the RF
detector to check for RF voltage at the cathode
(banded) end of diode D904 and at terminal 2 of the
connector. Make sure you have +12 VDC on pin 5 of
the board.
( )
Disconnect the gray wire from diode DW4.
P.A.
Use the following check to see if the P.A. transistors are
defective. Figure
4-3 shows the P.A. circuit board from the
component side. The shaded areas are connected to the
secondary center taps of coils L952 and
L953.
, ,
FOIL
Figure
4-3
(
)
Push
the HI PWR button in.
(
)
Connect the common lead of your voltmeter to the
chassis.
(
)
Connect the input lead of your voltmeter first to one
foil and then to the other. At each foil, you should
obtain the following "normal" reading. If you obtain a
"bad"
reading at either foil, all four final transistors
should be replaced (these are only sold by Heath as a
matched set of four transistors).
NORMAL
BAD
-
TX (HI PWR) 0.65V 1.2V
RX OV 1.2V
Refer to "P.A.Circuit Board." Page 312, for additional
-
troubleshooting information about this section of the
Transceiver.
Refer to "Power Amplifier Warranty" on Page 281 for the
special one-year warranty on this circuit board.
To Next Page
Loading...
