ICOM IC-255A Improvements (PL/RX)

Discussion in 'Radio Circuits, Repair & Performance' started by W8WJW, Jun 23, 2021.

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  1. W8WJW

    W8WJW Ham Member QRZ Page

    Hello, 3 questions on improving a purchased ICOM IC-255A.
    Looked at CommSpecialists 'fax' sheet to add a CTCSS / PL board to the ICOM IC-255A.
    CS sheet says to connect 'Tone Output" to "Base of Transistor Q7 (2SC945)".
    Anyone know if that is correct? My Q7 is not a 2SC945 for starters and it doesn't appear to go to the deviation circuit? Anyone that can confirm connection point for SS-32 or SS-64 tone board to a IC-255A ?

    Audio is killer loud, but you also hear 'eggs frying' while receiving a strong repeater - suggestions on making reception a bit more "noise free" or what could be 'off'?

    Normal 'high power' ~25 is fairly decent, but pulling out the knob for 'low power' results in a continuous tone in receive while at the 1W power? Again, suggestions, ideas?

    The repeater offset knob is "goofy". Normal works fine in the 146 band, but 'normal' in 147 band shoots you to -600KHz, not 600KHz. is that an issue with the rig, or should they have simply labelled the button -600K / +600KHz /Simplex?

    Any suggestions appreciated.
  2. W9GB

    W9GB Ham Member QRZ Page

    QRZ Archives (2011), same question.
    John -
    You will have to contact Icom Service for paper “Service Packet” on IC-255A.
    Never Scanned, that I am aware of. Scott Macon at MTS may have a copy.
    Icom IC-255A VHF 2-meter transceiver
    Manual (31 pages), Block Diagram page 28
    Page 20 outlines the radio designer’s criteria for Repeater Offsets.

    ComSpec SS-32, SS-64 CTCSS encoder
    Hook-up for Icom IC-255
    Transmitter section of Radio,
    wiper of the deviation pot, which is easily accessible on the IC255A, is common insertion point.
    That is highlighted in photograph in the manual.
    Last edited: Jun 23, 2021

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