SRN - 1322
APC - 355,376,402, 432,466,511,
720, 426,500,623, 722, 604, 624
617, 221, 671,412, 494, 465,
527, 620, 310, 326, 276, 761

Memo To: SRN Mailing List August 2000
From: Subscriber Product Group - GSPDC Americas Informational Only
Subject Periodic Preventive Maintenance for Portable and Mobile 2-Way Radios

Products Addressed:

Astro Subscriber Products (Astro Saber, Astro XTS3000, Astro XTS3500, Astro Spectra, Astro Consolette) Analog Subscriber Products (HT1000, Visar, MTS2000, MTX8000/9000, Analog Saber, MCS2000, Analog Spectra, Spectra Consolette)

Today's high-end two-way subscriber radios are much improved over previous generation products in the area of periodic maintenance and adjustment requirements. The replacement of mechanical potentiometers and tuning slugs with electronic adjustments has resulted in a stabilization of tuning values over environmental extremes and aging. However, to insure optimum RF performance and peak efficiency, periodic preventive maintenance is necessary. The purpose of this advisory is to describe the components of an effective preventive maintenance program

  • Periodic Adjustment for all Radio models described above
    • A. Reference Oscillator - This is the only adjustment that requires periodic attention in all radio types. The FCC and Motorola requirements for frequency accuracy in the bands of interest are shown in Table I. Motorola guarantees that all new radios are shipped from the factory in compliance with these limits. As the reference oscillator crystal ages, it will tend to drift, almost exclusively downward in frequency. The amount of drift from aging decreases over time, and eventually becomes negligible. It is advisable that this adjustment be checked when the product is placed in service and annually thereafter. The frequency counter used for this measurement must have an accuracy of 0.1 PPM or better.
      Frequency Band Allowable Freq. Approx. Allowable

      Error (PPM) Freq. Error (Hz)



      VHF (20/25/30kHz) 5 800
      VHF (12.5/15kHz) 3 470
      VHF (Astro) 2.5 390
      UHF (20/25kHz) 4 1850
      UHF (12.5kHz) 3 1375
      UHF (Astro) 2.5 1150
      800 MHz 2.5 2125
      800 MHz (Astro) 1.5* 1275
      900 MHz 1.5 1400
      * Also applicable in 821-824 and 866-869 Analog Trunking
      Table I: Frequency Accuracy Requirements
    • Other Adjustments
      The other tuning adjustments in the radio (Power, Deviation, Mod Balance, etc.) will change very little over the lifetime of the product, assuming no component replacements or damage. It is advisable to spot check these parameters occasionally, but annual checks/adjustments are not required. All adjustments should be revisited when a radio is repaired.

  • Mechanical Considerations
    • Periodic visual inspection and cleaning* is recommended. Frequency depends on the environment in which the product is used. * Mild detergent and water used sparingly. i.e. Joy dish soap/water
    • In portable radios that are ruggedized, seals must be replaced annually to insure continued seal integrity. Pressure checks are necessary upon re-assembly. Pressure check kits are available through the Accessories and Aftermarket Division or through Motorola Service Depots.

  • Intrinsic Safety Considerations
    Repairs and maintenance to intrinsically safe portable radio units should be performed at service centers that are audited by the Approving Agency, (for example: FM, CSA, etc). Tuning operations can be performed by service centers that are not agency approved. Contact Motorola if additional information is needed for intrinsically safe radios.

Informational Only, No Labor or Parts Warranty Implied