I have a 47 DeSotowith a Mopar 602 (Colonial 671A). I'm trying to troubleshoot it. No buzz.

All the diagrams show a 4-pin vibrator, with power and ground to the large pins, and an alternating ground from the small pins. The charts call for an R43697, ot just 43697.

I have a 43697M. I opened the can, and found only three of the pins wired. It looks original inside.
Did someone just put in the wrong vibrator?

:I have a 47 DeSotowith a Mopar 602 (Colonial 671A). I'm trying to troubleshoot it. No buzz.
:
:All the diagrams show a 4-pin vibrator, with power and ground to the large pins, and an alternating ground from the small pins. The charts call for an R43697, ot just 43697.
:
:I have a 43697M. I opened the can, and found only three of the pins wired. It looks original inside.

There should be 4 connections to the vibrator; 3 to the the primary of the transformer (center tap to B+), 1 to ground.
:Did someone just put in the wrong vibrator?

Hi

Most vibrators used three pins. When the vibrator operates internally it shorts out the coil so the 4th pin isn't needed. Some did use all 4 with coil wired to two large pins. Some radios are wired so either type vibrator operates.

Later 12 volt vibrators were made with only 3 pins.

Norm

::I have a 47 DeSotowith a Mopar 602 (Colonial 671A). I'm trying to troubleshoot it. No buzz.
::
::All the diagrams show a 4-pin vibrator, with power and ground to the large pins, and an alternating ground from the small pins. The charts call for an R43697, ot just 43697.
::
::I have a 43697M. I opened the can, and found only three of the pins wired. It looks original inside.
:
:There should be 4 connections to the vibrator; 3 to the the primary of the transformer (center tap to B+), 1 to ground.
::Did someone just put in the wrong vibrator?

Thanks.

:Hi
:
: Most vibrators used three pins. When the vibrator operates internally it shorts out the coil so the 4th pin isn't needed. Some did use all 4 with coil wired to two large pins. Some radios are wired so either type vibrator operates.
:
: Later 12 volt vibrators were made with only 3 pins.
:
:Norm
:
:::I have a 47 DeSotowith a Mopar 602 (Colonial 671A). I'm trying to troubleshoot it. No buzz.
:::
:::All the diagrams show a 4-pin vibrator, with power and ground to the large pins, and an alternating ground from the small pins. The charts call for an R43697, ot just 43697.
:::
:::I have a 43697M. I opened the can, and found only three of the pins wired. It looks original inside.
::
::There should be 4 connections to the vibrator; 3 to the the primary of the transformer (center tap to B+), 1 to ground.
:::Did someone just put in the wrong vibrator?

If you cannot find a vibrator that'll work for your radio, you can modify your radio to work with the vibrator at hand.

A vibrator that uses all four pins will have a pin that goes to a set of points that only control the vibrator coil. Another pin will go to the other side of the vibrator coil, and also to the center moving points in the vibrator. The other two remaining pins will go to the outer stationary points. The set of points that operates the vibrator coil only will be closed when the vibrator is at rest. When the vibrator is electrified, the coil will be energized, and will pull the armature. This will open the coil points, causing the coil to de-energize, and the armature will swing back in the other direction. The process will repeat. Each set of vibrator points associated with the power transformer will open and close as the process continues.

A vibrator that uses only 3 pins will have one pin going to the moving points and the other two going to each stationary point. The vibrator coil will be wired across one set of points (one movable and its associated stationary). To use a vibrator of this kind in your radio, wire the two stationary points to the ends of the transformer primary. If your radio uses a rectifier tube of sorts, which it must, if it is to use any 4 pin vibrator, you don't really need to worry about the polarity to the transformer primary. You can follow the schematic if you wish, which will probably give you optimum results. Connect one side of your power source (6 or 12 volts, depending on what the radio's made for) to the moving points, and the other side to the transformer center tap. When the points are at rest, both sets will be open. The coil will be across one open set, and will also be in series with half of the transformer primary. It will be energized, and will pull its points closed. This will short the coil out and feed half of the transformer winding full power. With the coil not being energized, the vibrator armature will spring in the other direction, which will re-open the set of points that closed, and then close the other set of points. With the other set closed, the other side of the primary will be energized. The first set is now open, and the coil will also be energized, and will pull the armature back the other way. The sequence will start again.

For added protection of the points, you should have a resistor approximately 50 ohms across each point. I think that is the correct resistance, but I may be wrong. It's generally around 50 ohms. Your schematic might show a different value.

Thomas

Thanks for the tip.
I got the vibrator working with the 120 volts through a 60 watt bulb. Amazing!
The vibrator hums, and the rectifier tube lights up. Next step is to replace the eapacitors.

Hmmmmmmmmmmm......... I don't think that you're supposed to run the rectifier with the 60 watt bulb....just the vibrator.

The rectifier filament (if not an 0Z4) should run on its own from the radio's A supply (6 volts).

T.

No, I just juiced up the vibrator with it out of the chassis. When I put it back in the chassis, I could see the rectifier glow.
I ordered film and electolytic capacitors, and am standing by.

You can try the radio as-is. It might work. I have had several auto radios work alright with their original components. Most didn't work for more than 20 minutes, due to leaky audio condensers. You aren't as likely to damage the power supply in an auto radio as you are with an AC radio. Just monitor the voltage at the rectifier cathode from the get-go, and if it drops below a normal range, cut the juice.

Thomas