Grill electronic igniter module test

[goingjag]

I'm trying to determine a way to test the AA powered ignition module for my gas grill. It has a ground wire and 3 outputs to igniters.

The push button just provides a connection to a wire on the side of the battery housing, so the first thing I tried (along with a new battery) was a hard wire to replace the spring button combo, but no joy.

Would creating a little ground bar for it, putting a spark plug on one of the terminals and grounding the spark plug provide a test bed? I don't want to just try this and overload the module if it's not already dead.

It's not clear to me what those small ignition lines contain, it looks like a wire surrounded by ceramic e.g. a spark plug. I doubt all 3 of mine quit working, but given their environment, and before I spend the money on a new module I thought I would try to test it.

I tried putting a meter on figuring a quick hit would bounce it high, but I kept backing it down from 1000k volts to mili volts. I was getting a very slight reading at mili volts but I suspect I could have created that with static.

Any thoughts appreciated.

[jimmy101]

Those little igniters typically generate voltage spikes in the range of a few KV up to perhaps 10KV.

If the gap(s) is(are) too big it won't work. You can try shortening the width of the gaps and see if that works. Gaps will also work better if one or both of the electrodes are sharp since spark's will jump much easier between sharp points then they will between dull ones. IIRC, most of these setups use the BBQ itself as one of the conductors, so you can try to hold one of the "spark plugs" very close to the metal of the BBQ and see if it sparks. (Basically the same way an auto mechanic would test for a spark/no spark condition on a spark plug.)

Another test is to wire a NE-2 (neon) bulb from one of the "spark plugs" to the metal of the BBQ. When you push the button the NE-2 bulb should blink. (You can also use a small Xenon flash tube salvaged from a cheapo camera flash.) This works for both the AA powered sparkers and the piezo (no battery) sparkers. If the bulb flashes the circuit is doing something, though it doesn't prove that it is generating enough voltage to make a suitable spark.

Or, depending on how brave you are, you can just short the gap with your finger. It'll smart a bit if the circuit is working but "shouldn't" kill you. You want to short the circuit across you finger tip. Not from your finger tip to say your other hand resting on a metal part of the BBQ. Always best to avoid current across the heart.

These circuit really don't like being operated when the gaps are not working correctly. The internal voltage will spike to a very high value if there isn't a suitable gap and the circuit will find someplace internal to arc. That'll tend to burn through insulation or do other bad things. Sometimes these little HV generators have an internal "default" gap. That gap it is to protect the electronics from the very HV associated with operation without a suitable external gap. If the spark gap is to big then the circuit will automatically spark across the default gap and not fry itself. (Stun guns generally have a default gap.)

Another thing to consider is that to get sparks at the gap(s) you need to be actually getting voltage to the gaps. This is a HV circuit and the spark will take the path of least resistance. The resistance of the spark gap is very high, probably in the megaohm or more range. At these voltages typical wire insulation is pretty much useless, the wires might as well be bare for all the insulation does. So, trace the wires to make sure they never approach anything metal at a distance less than the spark gap width. You might even run the circuit (installed on the BBQ) in the dark and see if you can find sparks someplace where they are not supposed to be. Basically you want to use air as the insulator for the wires.

One last test would be to put an AM radio next to the BBQ and listen for noise on the radio as the circuit operates. A spark, even if it is where it isn't supposed to be, will generate a fair amount of RF noise which the radio should pick up. (My laptop has no problem getting an audio recording of the RF generated by a piezo sparker at a distance of a couple feet.)

[goingjag]

Thanks Jimmy101. After having fun with automobile spark, I'll pass on the finger test. A 120 AC "bite" is much easier to take than a kv DC one.

I suspect your point regarding the circuit internally shorting when the external gap is too big might be what is happening. This is a pretty good sized sealed unit that is built to generate a spark to 3 separate burner igniters, so it likely would want a place to go, or if designed poorly has already burned up internally.

Thanks again for all the ideas.

[dacflyer]

if its doing anything at all , you should hear some sort of ticking..
friend here had 1 port not working on her grill..found it to be a dirty connection right at the connector on the ign unit.

but yes a sparkplug would be a easy test tool or a old small neon bulb..spark plug night be easier to find in a junk box..

i also have seen that grill gunk can short the igniter points by the burners, gotta remember thats all charred food..very conductive.. make sure they all are clean. and dry.
use a wire brush if need be .. wet ones will short as well..