Icom IC-201, Manual

Page: 6 / 21

DL7MAJ, Oct 20
th
2015
Page 6 (21)
Premix
1) “CAL” (Calibrator) switched off
2) Receive “R”, mode USB
3) Connect Counter (AC-coupled) to Collector of Q3. Best use analog scope with Y-
output
4) Connect DC-Voltmeter or Scope with 10:1 probe to common cathodes of D4 and D5.
5) “RIT” centered: Trim R8 for app. 0,3VDC
6) Set “Coarse” to 144 MHZ (simplex).
7) Measure frequency; should be app. 15,239 MHz.
8) Check: Tuning “RIT” should change frequency app. +/- 400 Hz – symmetrically to both
sides
9) If not readjust R8 and check again – back to 7)
10) “RIT” centered again.
11) Measure frequency; should be app. 15,239 MHz.
12) Switch to transmit “T”.
13) Adjust R9 for exactly same frequency as 10)
14) Switch to “R”, “RIT” centered
15) “Coarse” 144 MHz: Adjust C6 to exactly 15,239375 MHz (X2)
16) “Coarse” 145 MHz: Adjust C5 to exactly 15,364375 MHz (X1)
17) “Coarse” 145 MHz DUPLX: Switch to “T” and adjust C70 to exactly 15,289375 MHz
(X3)
18) Check: 145 MHz in DUPLEX is on “RX” same as in 15 (15,364375 MHz)
19) Recheck 15, 16 and 17 in “R” and “T”
20) Connect AF signal (2kHz, 10mVpp) to MIC-Input
21) Connect Scope to Pin 9 of IC1 (MC3301P)
22) Mode “FM”, Transmit “T”
23) Adjust R52 for symmetrical clipping at Pin 9 of IC1;
adjust amplitude with “MIC GAIN” and R53 if necessary
24) DC-Level at Pin 9 of IC1 should be app. 4,5 to 5,0VDC without AF-Input
25) Check that AF at Pin 9 of IC1 is just clipped
26) Connect Jumper P1 to J3 and adjust FM-Deviation with R61 to 5.0kHz
27) Connect Jumper P1 to J4 and adjust FM-Deviation with R62 to 2.5KHz (for narrow
band FM)
28) Switch back to receive “R”
29) Note: Maximum deviation with constant AF input will be at 2.4kHz due to phase
modulation and frequency response of IC1 (R57/R59/R60/C59/C60)