Results 1 to 1 of 1

Thread: ICOM ID-51A Plus 2 (and other versions) 76-108 MHz restoration

  1. #1
    Join Date
    Dec 21, 2011
    Posts
    4,168
    Thanks
    2,558
    Thanked 5,295 Times in 1,571 Posts
    Country: Canada

    Default ICOM ID-51A Plus 2 (and other versions) 76-108 MHz restoration

    The existing modifications posted on mods.dk :

    Remove D9 - Extended RX (0.520-1.710, 88-108, 108-174, 380-479)
    Remove D10 - Extended TX VHF (137-174 MHz)
    Remove D11 - Extended TX UHF (400-479 MHz)

    These are all correct. They're all on the top side of the logic board. D9 is not placed at factory in USA/Canada (and other regions).

    I found a new modification, which is very difficult to perform, after studying the service manual and performing the modification, to verify results.

    Restore 76-108 MHz WFM (Already present in EUR, ITR, EXP, CHN and AUS versions). Other regions are only 88-108 MHz.

    76-88 MHz is used in some countries for broadcast radio. I suppose it could have other uses for tracking third harmonic CB interference or something, but it's not really all that beneficial to North America users. Regardless, here it is.

    - Disassemble radio.
    - CAREFULLY remove LCD display (ribbon cable ZIF socket is underneath LCD, VERY FRAGILE, be careful!)
    - Remove all six screws from logic board.
    - Desolder volume/channel switch assembly. There are six points.
    - Carefully lift logic board out of radio frame.
    - Locate pad for diode D8 on underside of board. See attached image.
    - Install D8. You may reuse the diode from D9, D10 or D11, as it is the same p/n.
    - Reassemble

    Click image for larger version. 

Name:	ID51A-logic.jpg 
Views:	9 
Size:	94.1 KB 
ID:	11326

    Once you have removed D9, D10 and D11 and installed D8, your radio is now fully converted to the EXP region version. The EXP region version offers the most frequency coverage.

    If anyone has the mod to add the 1750 Hz tone burst option, please post it. I couldn't figure it out based on the diode logic options from the other regions, which also come with limited frequency coverage. (I have a feeling D9/10/11 are master controls, regardless of region, but 1750 Hz is tied to one of them).

    B = Bottom, T= Top

    D5 B EUR, UK, USA, KOR, EXP, EXP-01
    D6 B UK, ITR, EXP-01
    D7 B EUR, ITR, KOR, EXP-01
    D8 B EUR, ITR, EXP, AUS - CONTROLS 76-88 MHz
    D9 T EUR, ITR, KOR EXTENDED RX
    D10 T EUR, UK, ITR, USA, KOR, EXP01, AUS UHF TX EXP
    D11 T EUR, UK, ITR, USA, KOR, EXP01, AUS VHF TX EXP
    Last edited by Mars; Dec 26, 2017 at 06:10 PM.