cross reference NEC SM 214 C Hall effect

[UncleA]

Trying to cross reference NEC SM 214 C Hall effect used in 1985 and newer Honda motorcycle speed sensors which are no longer available from Honda. I've attempted searching Google and many cross reference websites with no luck.

NEC SM 214 C is printed on the part. It has 3 leads and mounts on PCB, pins soldered on underside of PCB. It uses 12volt supply of course, and goes to bike's LCD showing speed, RPM, etc. It should generate 8 pulses for each revolution of front tire. Any ideas of what part I can use to replace it?

 

[BradtheRad]

It sounds like you've got a hall effect switch (as opposed to a hall effect sensor, although they are similar).

Do you find it located close to a toothed disc that spins? That is a typical mechanism for getting the device to provide pulses.

Perhaps you can try any 12V hall effect switch, as long as it matches pin-for-pin?

An automotive parts store might have 1 or 2 to choose from.

About using a 12V supply. I believe it's more common to find 5V type. If you are good with a soldering iron you might consider making a homebrew DC volt shifting circuit. Something to do with a zener diode, transistor, and resistors.

There is 'SM' in the name. Does this mean surface mount? If so then it will not be easy to remove, nor to install a replacement.

Caveat: You risk ruining something else in the vicinity if you do it yourself.

 

[UncleA]

I believe you may be correct about a 5v supply to this circuit. Test procedures from Honda only state 0v to 5v output pulse, 8 times per wheel revolution. There is no mention of supply voltage.
It is not a surface mount. It is an insertion type, looks like a “TO 92” package.
Black case is 0.35” high, 0.25” wide, 0.10” deep with white lettering.
Looking at front of package with NEC SM 214 C on it, the Vin is left pin, center pin is 0v to 5v output pulse, right pin is GND.
When mounted on PCB, body is bent backwards so it is parallel with PCB and lettering is facing up.
Top of package points to 1/2" diameter round magnet which is driven by shaft from front wheel through gears.
Air gap between rotating magnet and top of package is about 0.09”
Other components on PCB are 2 diodes and 2 capacitors. Entire unit is grounded. Total size of "speed sensor package" on front axle with PCB inside aluminum case is about 2” X 1 ½” X 1”.
I hope this gives you a better mental picture of the part and its application. Any cross reference of this part would be greatly appreciated.

 

[BradtheRad]

A few turn up in a simple Google search.
None appear to be an exact substitute.
One cannot accept a supply as high as 12V.
Another only puts out pulses of 0.4 V amplitude. Etc.

Examples:

https://www.newark.com/honeywell-s-c/ss49/ic-hall-effect-sensor-to-92-3/dp/95F5207

https://www.newark.com/honeywell-s-...J1786?in_merch=true&MER=ALT_N_L5_Sensors_None

The above do not appear suitable.

Here's a roundup describing various types:

https://sensing.honeywell.com/index.php/ci_id/54924/la_id/1/document/1/re_id/0

There are many mail-order electronics houses where you can look over a variety of hall effect switches. Example, Mouser, Jameco, Digi-Key.

Typical price is a dollar or two. They charge several dollars to ship just a few items.

If you are willing to experiment, then you might purchase a few. Look for a unipolar non-latching hall switch which can take 12V supply.

Internally it may need a pullup resistor so that it will produce 5V pulses.

It would help if you could verify whether the board receives a 12V supply, or a 5V supply. A meter reading at a couple of spots should tell you.

Since the board has few components, it would pay you to make sure something else isn't causing the breakdown.

Did you examine for cracks in traces and solder joints (using a magnifier)? It's a location which gets heavy vibration.

Also are the diodes zener type? If so then it will help determine what specs apply to the hall switch.