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- MODIFICATIONS FOR THE ICOM IC211
- ================================
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- SSB & CW VARIABLE POWER
- Place set with the controls towards you and remove lid.
- If necessary check FM and CW power.
- Connect set to known good dummy load and power meter. Locate R13 and R14 on
- small board behind the front panel RF power control. With RF power control on
- max, TX on FM and adjust RH pot (R13) for 10-12watts. Turn RF power control
- fully down and adjust LH pot (R14) for desired low power setting (min 200mW).
- Short key jack at rear of set, switch to CW, TX and adjust R129 for
- 10-12watts the same as on FM. Switch off power.
- Locate brown wire to left of Xtal filter. It runs from next to R258 to near
- R327 and is marked with a small b on the main unit board layout diagram. Cut
- this wire at the front end and solder to emitter of Q65 or the purple lead
- marked I on main unit layout.
- Solder the slider of a 4.7k preset to the LH end of the YELLOW WIRE behind
- R14, then solder a 3.3k resistor to a leg of the preset, run a wire from
- this resistor to top of R272 (scrape paint off before attempting to solder).
- Switch on. Switch to CW, TX and with front panel RF power control fully down
- adjust the 4.7k preset for desired low power level (min 200mW).
- SSB power is same as CW.
- The front panel control now affects FM, CW & SSB power levels.
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- RX GAIN
- Replace R6 (220ohm) Q2 with a 25k pot. This gives about 20-25db front end
- attenuation but will not increase the background hash. This has been tested
- by ICOM UK and is OK.
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- SIMPLE 600k TX SHIFT
- 1 Turn on set from cold (NO MEMORY) FREQ =144.000
- 2 Select VFO A
- 3 Tune to 144.600
- 4 Switch to simplex or duplex as required. The VFOs will track together
- provided the MEM switch is on, even if the set is switched off from the
- front panel, provided power is left connected.
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- PIN CONNECTIONS FOR 24 PIN MOLEX PLUG
- 1 Discriminator output 13 N/C
- 2 DC 13.8v from power switch 14 control for 100hz or 5khz step
- +5v for 5khz step
- 3 PTT when grounded =TX 15 Lock input to lock dial externally
- 4 Audio O/P unaffected by volume 16 UDC input up/down external control
- 5 TX AF input 17 Scan input
- 6 +9v on tx 20ma max 18 CL input to clear freq
- 7 External alc input 19 FCL input clears last entry
- and inputs MHz
- 8 Ground 20 K0 control data
- 9 NC 21 K1 control data
- 10 NC 22 K2 control data
- 11 NC 23 K4 control data
- 12 nc 24 K8 control data
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- TAKE GREAT CARE NEVER TO APPLY A VOLTAGE OUTSIDE THE -0.5v TO +5v TO
- TERMINALS 15-24 inc AS THESE ARE CONNECTED TO THE LSI CHIP
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- NOTES ON DATA INPUT
- PIN 15 Dial locked when 0v applied released by +5v or NC
- PIN 16 & 17 are used as a pair
- When 16 is low and a pulse is given to 17 freq counts down
- When 16 is high and a pulse is given to 17 freq counts up
- When the input to 17 is a square wave the min period between pulses =640usec
- Min period after last leading edge of an input to 17 before next change
- in 16=640usec
- PIN 18 +5v clears LSI to 144.000MHz
- PIN 19 selects MHz as follows:
- +v on 19 and k0 = 144MHz
- +v on 19 and k1 = 145MHz
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- After inputting the MHz the remaining digits are input in sequence.
- The required digits being selected by applying +v to the appropriate inputs
- as in the table.
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- 1 K1 6 K2,K4
- 2 K2 7 K1,K2,K4
- 3 K1,K2 8 K8
- 4 K4 9 K8,K1
- 5 K1,K4 0 K0
-
- A KEYPAD DIODE MATRIX CAN BE CONSTRUCTED AS FOLLOWS using 1N4148 diodes
- X is position of diode
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- PIN
- ON
- RIG KEY PAD NUMBERS
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- 1 2 3 4 5 6 7 8 9 0 144 145 146 147
- K0 X X
- K1 X X X X X X X
- K2 X X X X X X
- K4 X X X X
- K8 X X
- FCL X X X X
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- A SUITABLE PSU IS AS FOLLOWS
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- PIN 2---------------/\/\/\/---------------------------------------
- 330ohm Z / 1 / 2 / 3
- --- --- ---
- = = =
- pin 8---------------------------------- ------ -------- -----
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- to diode matrix line 1 line 2 line 3 ETC
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- Z = 5.1v zener diode
- = = 0.1uf cap to gnd
- /1 = key 1
- /2 = key 2
- /3 = key 3
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- There is some more, but I hope this will enable you to build the keypad.
- Most of this except the power mod will work on the Icom 245 as well.
-
- 73 Julian G6LOH
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