Mitrek volume and squelch resistors

by AK2O


The scoop

The repeater conversion is based on the OEM Motorola manuals for VHF P/N: 68 P81045E70-0-01
and the UHF, P/N: 68 P810445E75-A.

As you probably know by now, the "deci" audio come from J-10, pin 9, then goes through a 4.7 uf cap, to the volume and squelch pots. What is missed are two series resistors, feeding each of these pots. The first two areas in the Mitrek manuals show mixed documentation. For example page 7 does show them:

















but not page 9 (receiver section).

















However, on the control head diagram, on sheet 1 of 2, control head, HKN4000-6A, does show them, as R105, 10K feeding the top of the volume pot, and R104, 3.3K feeding the top of the squelch pot.

















As mentioned on the first (Mitrek) document, leaving them out does not seemed to cause any problem with loading or squelch operation. If you need larger version of these images, just click in the center of image.

These diagrams are available in PDF version as well.

The author apologizes for the poor quality and the first two being upside down. Time is limited in this area.

  • First page

  • Receiver section page

  • Control Head page

    Copywrite: AK2O 2005 and later

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