|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.
POLARITY and PRIMARY CIRCUIT
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
FREQUENCY and DUTY CYCLE
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.
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