Modifications for the Icom IC-3200

Picture(s) of Icom - IC-3200

19-07-1998 Fix for IC-3200A used on packet English language
19-07-1998 IC-3200A TX to RX delay fix English language
19-07-1998 IC-3200A ext frq 430-440 MHz English language
12-01-2000 How To Expand The Coverage Of The Icom 3200A Mobile Radio. English language
17-02-2001 Frequency Extention RX / TX for ICOM 3200 E English language

19-07-1998
Fix for IC-3200A used on packet

For those poor souls who are trying to use the ic-3200a on packet here is here is some relief.

The problem is that when going from transmit to receive there is a delay in the receive audio turn on, which is on the order of 500 milliseconds and may be too long for some packet situations unless everyone had their txdelay set to 750 milliseconds.

There are two ways to resolve the problem. Both are fairley simple. the easiest way is to remove the muting on the audio P.A. I.C.

The instructions follow:
  1. Remove the cover that has the speaker attached to it (being careful of the wires)
  2. With T2. with the front of the radio facing you, look for the audio P.A. I.C. In audio P.A. I.C. in the right rear part of the radio next to the chassis it is marked "upc2002", looks like a to-220 case transistor, and has five leads on it
  3. Immediately to the left of the "upc2002" is a diode standing on end, and marked "D19" on the circuit board this is the diode that mutes the audio P.A. I.C. during transmit
  4. Cut one leg of "D19" and the audio P.A. I.C. will no longer be muted during transm ithis is all that is required and my tests have
Shown that the ic-3200a will work with other tnc's with txdelay's set as short as 150 milliseconds where before this modification a txdelay of about 600 milliseconds was required of the station trying to communicate to the IC-3200A.

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19-07-1998
IC-3200A TX to RX delay fix

For those poor souls who are trying to use the ic-3200a on packet here is here is some relief.

The problem is that when going from transmit to receive there is a delay in the receive audio turn on, which is on the order of 500 milliseconds and may be too long for some packet situations unless everyone had their txdelay set to 750 milliseconds.

There are two ways to resolve the problem. both are fairley simple. the easiest way is to remove the muting on the audio P.A. I.C.

The instructions follow:
  1. Remove the cover that has the speaker attached to it (being careful of the wires)
  2. WIth the front of the radio facing you, look for the audio P.A. I.C. In the right rear part of the radio next to the chassis it is marked "UPC2002", looks like a TO-220 case transistor, and has five leads on it
  3. Immediately to the left of the "UPC2002" is a diode standing on end, and marked "D19" on the circuit board this is the diode that mutes the audio P.A. I.C. during transmit
  4. Cut one leg of "D19" and the audio P.A. I.C. will no longer be muted during transmit and the receiver will respond almost immediately.
This is all that is req'd and my tests have shown that the IC-3200A will work with other tnc's with txdelay's set as short as 150 msecs where before this modification a txdelay of about 600 msecs was required of the station trying to communicate to the IC-3200A.

For those interested in an alternate method here is what has been done by WB4FOW on several other radios:

Since about 1985 most icom radios have pin 8 of the microphone connector wired to the speaker. This is convenient for the wiring of a tnc and is usually easy to modify so that receive audio is taken from the high side of the volume control.

To get back to the subject of the alternate modification for the IC-3200A, you can rewire pin 8 of the microphone connector to the high side of the volume control and avoid the muting circuit but if you plan to leave the tnc wired permenantly to the radio and also,to use the radio on voice you will need to change a resistor in the tnc so as not to load down the audio at the volume control. the value of this resistor will have to be determined experimentaly.

If anyone requires more information or assistance with this matter feel free to call clark, wb4fow, at 305-594-4313 monday through friday 10am to 6pm or leave a message in the w4nvu or aa4tm bbs's.

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19-07-1998
IC-3200A ext frq 430-440 MHz

Here is one modification that I found that will convert your ICOM IC-3200A for operation on the 430-440Mhz band.
This is a very simple modification and does nothing to harm the radio, no trace cuts, changing IC's or any of those problems.
The only minor problem is that you lose all your memories when it is first done, so if you need to, wrtie those 2 meter assignments for re-entry afterwards. Since the radio will only operate on the 430-440Mhz portion of the UHF spectrum afterwards use on 440-450Mhz can only be done only after the modification is cancelled.

Just inside the front panel of the ICOM IC3200A on the top there is a circuit board that can be seen with the top cover of the radio removed.
There are several componets that can be viewed from this angle, look for a jumper marked "J-8", this is for reference only.

To the side of this jumper, towards the small ribbon cable going to the display there is another jumper labled "J-10", this is next to the Capacitor labeled "C-4", also in this neighborhood is a mounting screw (just for reference). The only "mod" that you need to make is to lift the jumper "J-10" for a few minutes and re-install the jumper back in the same location that it was removed from - THAT is all!

To un-do your "mod" turn off the radio and at the same time depress the "function" button and indicated in the owners manual and normal operation of the ICOM IC-3200A is resumed.

I have verified the frequency and sensitivity of the radio after the "mod" was completed and the frequency display is accurate but the sensitivity at the lowest portion of the band on my '3200 was a bit deaf, with proper tuning of the VCO would certainly allow better preformance.

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12-01-2000
How To Expand The Coverage Of The Icom 3200A Mobile Radio.
Author: Andy Moss VE3YES - andmoss@home.com


The ICOM 3200A will normally cover from 140-150Mhz and from 440-450Mhz.

The search function of the radio, which can be accessed in either VFO A or B, has to be used to make the radio exceed the above noted coverage limitations.


The search feature causes the radio to scan every frequency between the preset limits. The lower limit is in Channel 0, and the upper limit is in Channel 1. For example, if Ch 0 contained 144Mhz and Ch 1 contained 145Mhz the radio would search, starting at 145Mhz, down until it reached 144Mhz. Of course it would stop on any frequency that broke the Squelch threshold.
If you changed Ch 1 to 446Mhz, the radio would search between 446Mhz and 144Mhz. However, it would skip 150.005Mhz to 439.995Mhz.

The trick is to change channels 0 or 1 to a frequency that is outside of the normal coverage range. Thus when you want to go outside of this range, use the search function in VFO mode with the squelch control fully counter-clockwise.

First, decide on whether you wish to go above 150Mhz, below 140Mhz, above 450Mhz or below 440Mhz. Please remember that the upper range will be in channel 1 and the lower range will be in channel 0.


Confused??? I thought so....How about an example.


Mission: receive normal coverage plus from 150Mhz to 152Mhz.


Steps:
  1. go into VFO A mode.

  2. change the off-set to 10Mhz in the minus mode.

  3. select a tuning step of 15Khz

  4. select a frequency of 150.000Mhz

  5. press function.

  6. press and hold, very important not to let go, MR button.

  7. simultaneously turn channel selector knob one notch to the right.

  8. let go of MR button and press VFO select button TWICE.

  9. observe that frequency in VFO A is now 150.015Mhz.

  10. repeat from step 5 until frequency in VFO A is 152.000Mhz.

  11. store this frequency in channel 1 by pressing MR button.

Notes:

Be careful, the radio will transmit out of band.


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17-02-2001
Frequency Extention RX / TX for ICOM 3200 E
Author: Thomas Zimmat - do6ftz@tntweb.de


  1. Remove power + antenna

  2. Open radio

  3. Locate diode matrix (located behind display unit)

  4. Install or remove Diodes (Tables below )

  5. Reassemble radio

  6. Reset TRX
VHF                  D 15  ---  D 16 ---  D 17   ---    RANGE
                     ========================================
                     open       open      open      144 - 154 
                     set        open      open      144 - 146
                     open       set       open      140 - 148
                     set        set       open      140 - 150
                     open       open      set       144 - 156
                     set        open      set       140 - 154
                     open       set       set       140 - 150

UHF                  D 19  ---  D 20 ---  D 18 ----  RANGE
                     ========================================
                     open       open      open      430 - 440
                     set        open      open      432 - 437
                     open       set       open      430 - 440
                     set        set       open      430 - 440
                     open       open      set       440 - 450

All the Modifications worked out pretty good. But I haven't found out what happens when you set all 3 Diodes in VHF and UHF.

If somebody finds out,let us know.

Remember it is not allowed to transmit outside of hambands !!

VY 73 de DO6FTZ

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