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Rcexl sensor problems

Old 10-18-2015, 09:22 PM
  #76  
CARS II
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Kalps
The answer to some of your questions are already posted on page one and two like positive piston stop.
Page #2
Post #35

Last edited by CARS II; 10-19-2015 at 07:54 PM.
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Old 10-21-2015, 09:05 PM
  #77  
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Thankyou
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Old 11-01-2015, 01:29 PM
  #78  
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Here is another video on the instal of the CH Ignitions sensor.

https://www.youtube.com/watch?v=Oc5f8s6HCPc&feature=youtu.be

https://www.youtube.com/watch?v=ReId...ature=youtu.be

Last edited by CARS II; 11-01-2015 at 02:42 PM.
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Old 11-01-2015, 05:26 PM
  #79  
CH Ignitions
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Hi Bill, tried to call you over the weekend couple times and I talk with lovely Darlene.
Send me one of those sensors.
Bill are those the plastic molded where you can not pull the wedge out and take the sensor/wire out and replace with a new?
The single sensor with marking 581k1 ( is a allegro part in SMT form) will be the one in question and this is the one that Liang
Used for a year I think and for some reason some may be doing that.
Currently he is not using any of those anymore, went back to regular 3 Pin Sip format as you seen in one of the postings above, showing the wire ,senor and housing.
The new sensor is still molded in plastic housing....I have not ask ...but I think Liang went away from the plastic/wedge assembly and he is using the plastic injection mode.
Can injection be a problem on OLD SMT?...Yes, typically a re-flow oven can be set up with different curves.
The data sheet recommend 240C for 10 sec for soldering .
I do not know the specs on the plastic injection mold he uses and this is PURE speculation based on experience and not actual facts.
If plastic do not cool fast enough when is in molding processes ...this can affect the parts.
I learn this in hard way when tried to use a toster oven for re-flow. Had to spend time and money to replace all PIC controllers.
But know I have the re-flow oven and makes a world of difference. Hope next year to invest 6-8k in a pick and place machine so I do not have to place the small parts by hand,
my eyes do not want to cooperate ....hope to be able to get the machine and then I can come up with more stuff.
Attached is a Picture direct from Liang with in use sensors.
The only SMT he uses ( first left) , is for some special applications dual sensor ; and not the one here in question.
The middle one SIP3 is the widely used and this is the one that he is using to replace the SMT sensor that some had issues.
The last on the right is a Dual sensor made from 2 single sip 3 units.






I hope this will clear more clouds.

Thanks
Adrian
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Old 11-07-2015, 11:48 AM
  #80  
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Yesterday I had two good flights on my Citabria, very reliable idle and transaction from low to high rpms.
The CH ignition sensor did its job as expected, perfect

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Old 11-07-2015, 06:51 PM
  #81  
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+1
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Old 11-16-2015, 09:15 PM
  #82  
bcchi
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Originally Posted by BadAzzMaxx View Post
The problem with the double spark on the RCexl sensors has been going on for over a year, there are a couple of the well known RC engines that have gone with a different ignition company because of the problem.

When I found the problem I started replacing the sensor on the RCexl when I sell and have not had a problem with the ignitions.


The only RCexl ignition I sell are the twin ignitions and got a new order last week and they still have the problem sensors with them.


On the timing, If you can not believe the manufacture who can you believe.



Milton
Got the pulse switches .Have not tested any of them. Waiting for small heat shrink and new buggs.Then I will redo some of them.
busy building new airplanes. I am building four 82 span Road Runners just for the 20 size gas . I have one flying fly s great of course. I am a stick builder.
BCCHI Tired old CH guy. AMA 2599
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Old 01-08-2016, 06:28 AM
  #83  
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I very well may of gotten a bad sensor. I got it on eBay from AGM. It's the injection molded one.
While checking the timing I noticed a spark just after entering the sensor.
This is an older ignition on a DLE 30.
It was noticeable when rotating the crank extremely slow.
I havnt tried starting it
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Old 01-09-2016, 02:53 AM
  #84  
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Any intermittent action of the sensor will cause a spark. For example, The sensor "makes" or conducts as the magnet first approaches the sensor but while the magnet is fully under the sensor, the sensor releases, (There's a spark!) and then as the magnet starts out from under the sensor, the sensor conducts again and releases creating a second spark.

The sensor should conduct when the magnet approaches and stay that way until the magnet departs from under the sensor.
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Old 01-09-2016, 09:24 AM
  #85  
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Originally Posted by kerwin50 View Post
I very well may of gotten a bad sensor. I got it on eBay from AGM. It's the injection molded one.
While checking the timing I noticed a spark just after entering the sensor.
This is an older ignition on a DLE 30.
It was noticeable when rotating the crank extremely slow.
I havnt tried starting it
Sounds like you have one of the problem sensors. Replace with one from RC Extreme Power or CH ignitions and don't look back.
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Old 01-09-2016, 09:25 AM
  #86  
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Originally Posted by w8ye View Post
Any intermittent action of the sensor will cause a spark. For example, The sensor "makes" or conducts as the magnet first approaches the sensor but while the magnet is fully under the sensor, the sensor releases, (There's a spark!) and then as the magnet starts out from under the sensor, the sensor conducts again and releases creating a second spark.

The sensor should conduct when the magnet approaches and stay that way until the magnet departs from under the sensor.
Good description of the problem!
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Old 11-06-2016, 12:39 PM
  #87  
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Some of the ignition modules I tested would fire the plug twice, as mentioned by w8ye, when the magnet first approached the sensor and again when the magnet left the sensor. Most of them that I tested would fire the plug only when the magnet left the sensor.


I like to use a tester that uses an LED to verify that the sensor does not have any "intermittent" operation. The LED should light when about half of the magnet gets under the Hall sensor and go out when about half of the magnet leaves the sensor. If the LED "blinks" while under the sensor, there is a problem.


The ignition module is "triggered" by the Hall sensor when the output voltage falls from the applied voltage to zero. The Hall sensor is designed to make that fall very quick, like an "edge" instead of a "slope." After the "trigger" is received, the ignition module delays the high voltage output to the spark plug by an amount of time as determined by the RPM.


The attached charts show the timing advance with two popular versions of ignition modules when set to 30 Degrees BTDC.
Attached Thumbnails Ignition Module Timing A0-1 and A0-2.pdf  
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Old 11-06-2016, 02:10 PM
  #88  
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And the sensors that fire twice run like crap and will knock your hand off or they may completely confuse the ignition module causing hard starting or poor acceleration if you do get the engine running. Any sensor that fires twice has a problem and is unfit for our use. I've only seen a few of the RCexl sensors exhibit this problem and they were commonly seen in 2014 - 2015. I assume most are out of the system now or will be discovered and replaced. Current production ones seem to be OK.

None of the bad sensors I've seen would show any kind of a blink on the tester. They could only be detected by observing the double spark (which didn't always occur when cranking the engine) or by using a scope. I have some saved waveforms but never published them here as most people really don't care about the subject.
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Old 11-07-2016, 10:49 AM
  #89  
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what is the correct timing for a da 85 cc engine I set it up for 28degress btdcthe engine ran hot after 5minutes I retarded it and it still ran hot.
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Old 11-07-2016, 11:02 AM
  #90  
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Being a DA, I'd contact DA for advice. That's what you pay for when you buy a DA engine.
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Old 11-09-2016, 08:04 AM
  #91  
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Originally Posted by edgersh View Post
what is the correct timing for a da 85 cc engine I set it up for 28 degrees btdc the engine ran hot after 5 minutes I retarded it and it still ran hot.
I did a quick search on Google and it is odd that the ignition timing for the DA 85 does not seem to be listed anywhere. I'm sure DA can provide the answer.

It has been my experience that most overheating problems were due to insufficient air flow. A good "rule of thumb" to use is to make sure that the air "exit" area, at the rear of the engine, is three or four times larger than the "intake" area at the front of the engine. The intake opening should be centered on the engine cooling fins for best results.


A lot of engine installations "look like" they meet the 1:3, or 1:4, ratio, a circle has more area than a rectangle with the same perimeter, but the best way to check it, unless you're a math genius, is to measure it. Just get some 1/4" square ruled paper and trace the intake and exit area shapes and count the number of squares inside each one.


If that ratio is within the “rule of thumb” ratio, then it is possible that the air intake opening is too small. In that case you can enlarge it, just make sure to open up the exit to maintain the ratio.


It is important to maintain the proper ratio in order to make sure that the air velocity, past the cooling fins, is high enough to provide cooling.

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Old 01-07-2017, 05:16 PM
  #92  
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A possible explanation of the "double spark" and 40something advance exhibited by some ignitions.

The spark is often triggered when the magnet LEAVES the sensor. In other words, when the signal falls when the magnet leaves. Now, if the engine is rotated slowly, as when checking for when the spark occurs, the signal from the sensor rises slowly as well, If the ignition is not designed with hysteresis on the incoming signal, it will at the point of triggering be indeterminate if the signal is above or below the triggering point. Any noise on the incoming signal or power lines will cause a the signal to be sensed as high/low, often many times before becoming high with the magnet well under the sensor. Of course the ignition will fire on the first downward noise signal, effectively firing the spark when the magnet is approaching the sensor. Under running conditions, the magnet is moving quickly enough that the noise does not have time to push the signal about the trigger point so the engine runs normal and quite well. A check with a timing light will show this quite clearly as I have done with a lash up timing light reminiscent of the old automotive distributor setting system. Some day, when I have the time I plan to build a timing light usable with our model motors using the signal, either paralleled with the ignition or an inductive pick up similar to the old automotive timing light,

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Old 01-07-2017, 06:03 PM
  #93  
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Originally Posted by Arceenut View Post
A possible explanation of the "double spark" and 40something advance exhibited by some ignitions.

The spark is often triggered when the magnet LEAVES the sensor. In other words, when the signal falls when the magnet leaves. Now, if the engine is rotated slowly, as when checking for when the spark occurs, the signal from the sensor rises slowly as well, If the ignition is not designed with hysteresis on the incoming signal, it will at the point of triggering be indeterminate if the signal is above or below the triggering point. Any noise on the incoming signal or power lines will cause a the signal to be sensed as high/low, often many times before becoming high with the magnet well under the sensor. Of course the ignition will fire on the first downward noise signal, effectively firing the spark when the magnet is approaching the sensor. Under running conditions, the magnet is moving quickly enough that the noise does not have time to push the signal about the trigger point so the engine runs normal and quite well. A check with a timing light will show this quite clearly as I have done with a lash up timing light reminiscent of the old automotive distributor setting system. Some day, when I have the time I plan to build a timing light usable with our model motors using the signal, either paralleled with the ignition or an inductive pick up similar to the old automotive timing light,
The explanation sounds good but that's really not what is happening with the sensors in question. Viewing the sensor line with a scope clearly shows the normal sensor turn on point as the magnet approaches the sensor. Then just after the normal turn on point and before the magnet leaves the sensor where it would produce the normal spark an early blip of turn off then back on produces the early spark. This is what is producing the early spark followed by the normal spark. Normal good sensors do not produce this short duration blip pulse. And yes, as you state, in normal operation the spark is produced as the magnet just passes under and goes away from the sensor or about half of the magnet being visible. The bad sensors do not exhibit the problem when connected to an ignition tester, only when connected to a real ignition box. Sadly, when I did the tests I didn't take any photos of the scope waveform as that clearly shows what is happening far better than any words I can post here. I could post a drawing but that just isn't a good substitute.

This thread is starting to get some age now so keep in mind most of these problem sensors were showing up about two years ago with some still being reported in 2016. I'm sure there are quite a few defective sensors still out there yet to be detected but I would have to believe the problem has long since been resolved in new production. I know none of the more recent engines showing up at the field have exhibited the problem.

On the down side, my bet is many people that have the bad sensors just dial back the timing to compensate for the early spark then never experience the full potential of the engine ... then complain about the engine. Sad because a $10 part can restore normal operation. Any engine that experiences way too much timing advance from the factory should be rechecked with a known good sensor before just assuming the mfgr. screwed up and set the timing wrong.

Last edited by Truckracer; 01-07-2017 at 06:06 PM.
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Old 01-21-2017, 05:26 AM
  #94  
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I still replace them with RCAME sensors just to be on the safe side.

Simple test is if the ignition fires when the magnet goes under the sensor it is bad, I to could not get one to do it with a sensor tester.

I have about 300 of them if anybody interested for a buck a peace. Most are probably good because I still replace them.


Milton
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Old 01-21-2017, 05:39 AM
  #95  
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I just had to adjust the timing on a PTE-36 engine. It was set at 24 degrees BTDC. I had to hog out the mounting holes to get it to 28 degrees. I thought I was going to have to put on a sensor with the strap.
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Old 02-18-2017, 09:29 AM
  #96  
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I was contacted by a member from another site regarding double spark on a new DLE 20, he said the timing was in the upper 30s, I gave him Milton's website address and suggested to get a hall sensor from him, I also gave him the link to this thread to get more info in the subject.


Yep, there still are some out there.

Last edited by CARS II; 02-18-2017 at 09:31 AM.
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Old 03-11-2017, 06:49 AM
  #97  
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Here's another one with the double-spark issue. This thread saved me a bunch of time. I would have chased my tail to exhaustion otherwise.

DLE35RA purchased in October last year from Tower.
A02 ignition box is dated June 2016.
Timing was 36 deg out of the box.
It will sometimes spark as the magnet begins to move under the sensor.
The tachometer display goes haywire when the errant spark(s) occur (all 4 digits come on briefly)

Truckracer has described the problem well. The sensor is "noisy" upon activation. Occasionally the noise manifests itself as a series of steps and that's when the errant sparks occur. I captured a few scope images to illustrate. The scope is looking at the white sensor wire (referenced to black) The ignition box energizes the white wire to about 1.5 vdc. When the sensor activates, the white wire is pulled to ground and the voltage goes to zero. This should not result in a spark, and won't if the transition is clean. The bad sensor is always noisy though like the first image shows. Occasionally it will look like the second image and that's when the trouble occurs. The deactivation is clean every time.

Thanks to Adrian at CH, I have a new sensor on the way, under warranty. I'll update this when it arrives.

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Old 03-11-2017, 09:36 AM
  #98  
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Nice to see the problem on the scope, and thanks.

I was going to say ("Nice to see the problem scoped out"), but decided not to....

AV8TOR
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Old 03-11-2017, 10:07 AM
  #99  
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Originally Posted by BRAL View Post
Here's another one with the double-spark issue. This thread saved me a bunch of time. I would have chased my tail to exhaustion otherwise.

DLE35RA purchased in October last year from Tower.
A02 ignition box is dated June 2016.
Timing was 36 deg out of the box.
It will sometimes spark as the magnet begins to move under the sensor.
The tachometer display goes haywire when the errant spark(s) occur (all 4 digits come on briefly)

Truckracer has described the problem well. The sensor is "noisy" upon activation. Occasionally the noise manifests itself as a series of steps and that's when the errant sparks occur. I captured a few scope images to illustrate. The scope is looking at the white sensor wire (referenced to black) The ignition box energizes the white wire to about 1.5 vdc. When the sensor activates, the white wire is pulled to ground and the voltage goes to zero. This should not result in a spark, and won't if the transition is clean. The bad sensor is always noisy though like the first image shows. Occasionally it will look like the second image and that's when the trouble occurs. The deactivation is clean every time.

Thanks to Adrian at CH, I have a new sensor on the way, under warranty. I'll update this when it arrives.


Thank you so much for the scope images! That tells the whole story. When I scoped the sensor output, I neglected to take any photos and wished a thousand times I had so they could be posted. It was difficult to convince people this problem existed even though Milton had discovered it some time before it became a greater, more across the board problem. Quite a few people said a Hall sensor couldn't act this way but these did. Others discovered the bad sensors would not produce a problem on all ignitions or the problem only existed some of the time. Thanks again for the images!
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Old 03-11-2017, 04:19 PM
  #100  
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Good Job Fellows
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