DZ HT-7, Инструкция по сборке, Страница: 22 / 44

Page 22
STEP-BY-STEP ASSEMBLY - Tests and Adjustments
( ) Carefully measure the volt ‐
ages below to be sure that
you have wired everything
correctly. These assume a
battery or supply voltage of
11.1VDC and can vary about
10%. Refer to page 39 for
help if your measurements are
substantially different.
( ) Adjust RV2 on the HT ‐ 7 ‐ 2
board to give a reasonable
sound to the audio without
feedback or excessive noise.
If the gain is too high, you
may start picking up short ‐
wave stations or strong local
AM broadcast band stations.
If it is too low, the range
of your HT may be limited.
( ) Press the PTT switch while
monitoring your signal on a
receiver tuned to 7.290MHz
(AM). Adjust RV1 and RV2 on
the HT ‐ 7 ‐ 1 board for the best
sound.
( ) Press the PTT switch and ad ‐
just trimmer capacitor C10 so
that the signal amplitude
peaks and audio sounds good
when the receiver is set for
exactly 7.290MHz.
Board Transmit/Receive Measurement point Voltage (DCV)
HT-7-2 R/T D3 cathode 11.1
HT-7-2 R/T Q1 base 3.1
HT-7-2 R/T Q1 emitter 2.4
HT-7-2 R/T Q1 collector 6.8
HT-7-2 R/T U3 pin 1 6.1 to 7.2*
HT-7-2 R U3 pin 2 6.6
HT-7-2 R/T U3 pin 4 5.5
HT-7-2 R/T U3 pin 8 11.1
HT-7-2 R U1 pin 3 4.4
HT-7-2 R U1 pin 7 8.8
HT-7-2 R U4 pin 8 8.8
HT-7-2 R U2 pin 14 11.1
HT-7-2
T
Q2 base 3.0
HT-7-2
T
Q2 emitter 2.3
HT-7-2
T
Q2 collector 9.0
HT-7-2
T
Q3 base 1.4
HT-7-2
T
Q3 emitter 0.6
HT-7-2
T
Q3 collector 10.9
HT-7-1
T
U1 pin 2 5.55
HT-7-1
T
U1 pin 3 5.55
HT-7-1
T
U1 pin 8 11.10
HT-7-1
T
U3 pin 1 11.10
HT-7-1 T U3 pin 2 0.00
HT-7-1 T U3 pin 3 5.00
HT-7-1 T U2 pin 8 5.00
HT-7-2 T U3 pin 2 8.0
Important: When
measuring volt ‐
ages in transmit
mode (PTT switch
pushed in), keep
transmissions
short and/or
connect a 50 ohm
dummy load or an
antenna to the
BNC jack to
avoid damage to
the output tran ‐
sistor.
See page 40 for
a component lo ‐
cator.
Blue measure ‐
ments are on the
HT ‐ 7 ‐ 1 board!
* Voltage is set by RV2 on the HT ‐ 7 ‐ 2 board