PeKo Radio
    The RVB-2 consists of the following circuitry (see fig 3 for a typical synchronous vibrator use).

  • Two low-On resistance MOSFETS to emulate the primary vibrator contacts.
  • A microprocessor controlled drive circuit to drive the MOSFETs such that frequency and duty cycle are identical to the
    original radio vibrator.
  • A voltage conditioner to convert the alternating voltage on the primary contacts to regulated DC voltage for the
  • Two high voltage rectifier diodes to emulate the secondary vibrator contacts in the case of a synchronous vibrator.
  • An optional enable circuit to turn the solid-state RVB-2 vibrator board ON or OFF (to emulate certain serial vibrators
    where the radio equipment turns the DC to DC conversion ON or OFF by means of removing voltage from the serial drive
RVB-2 Connection Instructions

    The standard voltage range of the RVB-2 is from 6V DC to 30V DC without the need to change any jumpers to
    accommodate different voltages within this range. It does not need external DC power: it derives its internal supply
    voltage from the primary transformer side. In this way you can use the RVB-2 without the need for modifications to your
    radio; the board will work as a drop-in replacement to your old radio vibrator, even for 3-pin asynchronous shunt
    For battery voltages below 6V and as low as 2V order the low voltage version of the RVB-2 (part number RVB-2xLV).
    For battery voltages above 30V, e.g. for 48V farm radios order the high voltage version of the RVB-2 (part number RVB-
    2xHV). This model operates from 24V up to 60V.

    If the (primary) circuit is negative ground (primary winding center tap Ctp connected to positive battery terminal as in
    figure 3 above) you need the A-version RVB-2A. For positive ground (primary winding center tap Ctp connected to
    negative battery terminal) you need the B-version RVB-2B.
    The primary circuit connection is the same for the A and B version: RVB-2 terminal A connects to ground and terminals B
    and C connect to each side of the primary winding (P1 and P2 in figure 3). See figure 8 below for a simplified connection
    It is important to determine the correct polarity. The RVB-2 is reverse polarity protected and it will not be damaged if the
    wrong version is used, however the vibrator will not operate. If you have trouble identifying the required version include
    the make and model number of your equipment in the order form. We have information on lots of vintage equipment on
    file here, chances are yours is included. Or send us a copy of your equipment vibrator power supply schematic and we
    will advise you.
    In rare cases the center tap is connected to ground and the original vibrator contact is connected to the battery voltage.
    In that case you would need version A if the connected battery terminal is negative and version B if the battery terminal is
    positive. Again include make and model in your order form or send us a schematic.

    If the vibrator circuit is synchronous meaning that the vibrator has connections to the secondary side of the transformer,
    connect terminals D and E of the RVB-2 to the secondary winding as depicted in figure 8 below (dotted lines). The diodes
    on the RVB-2 are placed such that the circuitry rectifies to a positive voltage on the secondary side. This is practically
    always how the circuitry is configured regardless of the polarity of the primary circuit.
    The rectifier diodes on RVB-2 terminals D and E (to emulate the synchronous secondary contacts) are always present on
    the board. So if you do not need these (in case you were replacing an asynchronous vibrator), just do not connect
    anything to these two terminals.
    In rare cases the vibrator circuit is supposed to generate a negative voltage. If that is the case put in a special request in
    the order form to reverse the diodes. Include the make and model number of the equipment so that we can verify
    required polarity. Or send a schematic.

    The standard version of the RVB-2 is always on and components to use the enable input are not placed. The reason is
    because this enable feature is hardly ever needed in vintage equipment, only certain types of military transceivers would
    rely on this when switching from TX to RX and vice versa, as earlier explained. If an enable input is needed, please order
    the appropriate version (part number RVB-2xxxEN) and connect terminal F of the RVB-2 to the enable signal. See figure
    8 below.

    The RVB-2 is set for 115Hz with a contact duty cycle of 40%. (40% ON / 60% OFF), as these turn out to be the
    parameters for most of the vintage radio vibrators that you will run into. Using jumper setting JP3 the RVB-2 will run at
    100Hz. However if you need a different operating frequency in the range of 50Hz to 400Hz or if you need a smaller duty
    cycle we can program this accordingly. Please add this as a special request in the order form.
    Please refer to figure 6. This shows an oscilloscope snapshot of the actual waveform coming from a mechanical vibrator
    (115Hz Mallory M3335C). Figure 7 shows the same waveform, but this time with an RVB-2 solid-state vibrator installed in
    the equipment. The pictures were taken as proof that the RVB-2 waveform maintains the original waveform perfectly in all
    aspects, to assure the smooth operation of your vintage equipment.
    RVB-2 interconnect diagram

  • A = ground (to vibrator reed contact)
  • B = MOSFET1 drain  (to vibrator first primary contact)
  • C = MOSFET2 drain (to vibrator  second primary contact)
  • D = Rectifier1 cathode (to vibrator first secondary contact – only synchronous vibrator)
  • E = Rectifier2 cathode (to vibrator second secondary contact – only synchronous vibrator)
  • F = enable in, positive going (only for RVB-2AxxEN model), negative going (only for RVB-2BxxEN)

    See figure 8 below.
Fig 3 - RVB-2 Solid-State Vibrator connected for Synchronous Operation
Fig 6 - Waveform as seen on Transformer Primary Side
using Original Vibrator Type Mallory M3335C
Fig 7 - Waveform as seen on Transformer Primary Side
using the RVB-2
Fig 8 - RVB-2 Solid-State Vibrator Connections