Speedometer Component Testing

[ToddinTO]

Looking through the shop manual and other threads the process was to press the start button without the key on the post, within 30 secs, check the voltage between the pulse line (purple/yellow) and ground while rotating the wheel.

The analog and digital (infocenter) speedometers are connected in parallel, does that mean that both gauges are faulty if neither reads a value, even though the voltage jumps between ~7 and ~7.5? I do see earlier in the thread that it looks like voltage difference should be several volts not just tenths of volts, perhaps the 5.6v zener diode in the sensor has failed (if I am seeing readings in the 7V range).


I may rig up a small frequency generator and feed the gauges with a pulsing DC signal to see if they register something . . . .

 

[Mekanix]

That pulse is too small. That is the problem. Mine is the same. New one goes from 5.2 5.2 to 8.9. I think it needs that level to make it sense a switch. You could use a t
Reed switch and resistor and achieve the same results with a spinning magnet.

 

[ToddinTO]

Wow, is that epoxy that fills that cavity where the electronics are in the speed sensor is tough!!!!

I used a hot air solder tool to heat it to the point where the plastic around it was beginning to melt and still had a difficult time to carefully remove the epoxy, it did not soften it much at all.

Despite best efforts one of the legs on the thermistor broke off, it looks like a barrel shaped device that is set into a hole drilled at the bottom of the cavity and glued in place, if I try to remove it, I fully expect I will damage the thermistor, likely not able to read any identifying marks.

I see from the schematic diagram in another post that there is a guess it is TTC05103JSY, does anyone know what the true value is for the part?

I can see the Zener diode is indeed a 5.6v 1/2 watt, and the Hall Effect sensor is the SS41, easy to source and replace.

I am considering just purchasing a replacement speed sensor from Ebay, but all the used ones are; in bad condition, pretty expensive, and no mention whether they are tested and functional.

 

[etemplet]

I start by spinning the wheel and looking for DC voltage on my meter, Then, knowing that the pick up is good, I put the key on and spin the wheel again. If there is no response on the speedo gauge while spinning the wheel, then the gauge is at fault.

Where are you measuring the voltage? At the Pin connector toward the back of the ski?

 

[etemplet]

Despite best efforts one of the legs on the thermistor broke off, it looks like a barrel shaped device that is set into a hole drilled at the bottom of the cavity and glued in place, if I try to remove it, I fully expect I will damage the thermistor, likely not able to read any identifying marks.

A member of this board installed a barrel type pick up on the sensor and it worked. I think it was pretty inexpensive $10 or so. Do a few searches on the forum. Good Luck !

 

[ToddinTO]

Thanks for the info, I will search for that thread.

I did measure the voltage at the connector where the lead from the sensor connects up to the three pin connector pretty much right over exhaust. I also checked the resistance in the cable from that point all the way through to the back of the speedometer, zero ohms.

We are quickly running out of nice days to take it back on the lake as winter approaches. I guess I will wait for the parts to arrive, reassemble, test the sensor out of the GTX, if its working OK, reinstall, and count the days to spring. . . . .

 

[chipskittles]

I just fixed my 97 speedster's paddle wheel sensor a couple weeks ago you just need an SS41 and zener diode per the schematic shown on post #6. The potting compound does come out without destroying the whole thing, a small flat blade screw driver helps. Slow and steady wins the race. Even going carefully removing small pieces I was only able to salvage half of the diode. Wire up the SS41 and diode as shown, and reinstall in the paddle wheel cavity with the ss41 against the "wall" facing the paddle wheel. It needs to be in line with the paddles. Hot glue works well for a potting compound. Accuracy for my application is good enough, When the speedo says 47 I think my wife's phone says 45.

Note - the schematic addresses the 2-wire sensor that is quite a bit more expensive than the older 3-wire sensor for whatever reason. I'm sure the 3-wire sensor is a similar circuit, probably an #SS41 but someone would have to figure out what the blue wire does on the 3-wire sensor/speedometer setup of the older design.

 

[ToddinTO]

Perfect, I have removed all the old components and epoxy, ordered some new SS41 sensors, I already some 5.6v Zeners , and also a 10K thermistor.

I have the 3 wire sensor, from the schematic, the 3rd wire is for the thermistor, water temp reading.

It may be next spring before I can try this out on the GTX, but will certainly update the thread with my results.

I have the same point of view on the speed, I am not trying to measure the speed to determine the optimal escape velocity to exit earth orbit or something, if it is off by 1 or 2 MPH that is fine, the GPS module from Candoo may be more accurate, but would also cost me $200CDN, the parts to fix the paddlewheel are about $5!

 

[chipskittles]

Ahh ok I didn't get into that part that because I just have the 2 wire sensor. A working speedo for me was more about being in tune with what the boat is doing. If it normally runs a top speed of 45 and one day will only do 40 that's a clue to pay more attention and figure out why before a motor blows, since they won't sound a whole lot different at 40 vs 45. Love me some working gauges

 

[ToddinTO]

Wow, what a long winter . . .

I replaced the components in the pickup device, new thermistor, SS41 and Zener.

Connected the unit to a 12 VDC supply through a 1K resistor, and spun the paddle wheel. The voltage reading now fluctuates between 5.5 and 8.5 VDC. The voltage variations seem to match what others have reported for a "good" sensor.

I will just reconnect the unit to the GTX, without refilling the small cavity on the sensor, or mounting it on the hull, spin the wheel and see if the speedometers react . . . . then reinstall if all is well.

 

[mikidymac]

E6000 glue works good for potting compound.

 

[etemplet]

Thanks for posting up on this. I think my standard speedo pick up fix is gonna be the Candoo GPS. LOL I just don;t have time.

 

[ToddinTO]

OK, nice day here, but still kinda cool for spring, but wanted to see if the pickup was working . . . .

Hooked the three wires from the pickup to the harness, connected the battery, put on the key, two beeps, great!!!!!

Selected the speedo on the digital gauge, and spun the paddle-wheel, did not register if it spun slowly, gave it a couple of hard spins and both the analogue meter and the digital registered about 6 or 7 mph! That was better than what I was getting last fall, spinning any number of times would not register anything on any gauge.

After I covered it up, it occurred to me, I could have hit it with compressed air or the garden hose to keep it spinning to see if speedo would maintain the speed or go higher than 7. I would prefer to actually put it on the water and give it a try, but sadly, all the launches are still closed here.....

I will get some E6000, seal it up, and remount it on the GTX, ready for the water.....

I will let ya know how it works out, and how it compares to the GPS speed.

 

[ToddinTO]

OK took out the GTX on Lake Ontario yesterday evening, light winds, swells only about 1 foot or so.

The rebuilt speedometer did not really register any speed under 5 mph, according to GPS on my marine radio, but over that, the gauge on the Seadoo was within about 2 mph of the GPS. I had to double check it a few times around 35-45 mph, it reported top speed of 58 mph.

The replacement thermocouple to sense water temp seems to work quite well too, pretty close to what is reported by weather service. I did not have another in water thermometer to compare the accuracy.

Since I now have a dozen of the SS41s and the Zeners, and based on how much help all the members of Seadooforum have provided . . . . if you have a dead speedo pickup, and you are certain that the pickup is the issue, and want it working again, PM me. You ship it to me and I will repair it and ship it back to you, no charge! Limited to the first 10 or so replies, I am not going to buy more SS41s, but no problem to use the parts I have already purchased.

 

[etemplet]

I've tried a couple of times to remove the sensor block from the back of the skis with no luck at all. They could have used less screws I am certain. What a pain. Perhaps I'll give it a try with some other tools one day.

I may well have a speedometer gauge issue on the RX where I installed the Candoo GPS speedo. It works when it wants to and registers about 5mph too slow according to my phone GPS. PIA for something you don't need at all.

 

[ToddinTO]

Those screws are indeed overkill for the sensor, two would have done it.

I put a few drops of CLR cleaner directly on the nuts and let it sit for a few days, even though they are stainless, I still noted a bit of white residue on the nuts.

I used a Phillips bit on a 1/2" ratchet to remove them slowly as to not damage the brass inserts in the plastic housing, but I could not find a Phillips that fit perfectly, perhaps these are JIS screws similar to what are on the carbs, and not Philips at all!

Despite being careful and slow to remove them, a couple ended up with cracks in the plastic around the inserts. When reattaching, I used longer stainless "Philips" bolts, put a large stainless washer on top of the sensor, and capped it with a stainless nut with the nylon insert.

Honestly, I am not too interested in the speed that much either, but I am sure there will be discussions like . . . my max speed was xx today from the family after a day of riding. It is more about having all the pieces of the GTX functional, rather than the bare minimum. I am sure the day will come when I will sell it, and to state that all the features of the unit are working as designed can only help.

When I bought the GTX the engine was not running, gas gauge did not work, speedometer sensor was bad, had old grey tempo lines, carbs needed a rebuild, happy to say now that all these have been addressed, time for some fun!

 

[etemplet]

CLR... Hmmmmm.... I'll have to try that. No arguments on fixing the gauges on personal skis. I restore a lot of them so I don't have the time to play around. One day I'm gonna sit down and figure this out. LOL I have (2) GTXs carburated. Those are the only two skis I claim. Thanks so much for sharing.

 

[ToddinTO]

Here of some pics after it was installed...

 

[etemplet]

It that thing in the groove.the Illudium Q-36 Space Modulator ??

 

[ToddinTO]

Why yes Marvin, that is exactly it!!!!

Sorry, hard to take pics once it is back on the Seadoo, here it is standalone . . .

The three parts which had to be replaced are buried deep in the epoxy immediately behind the paddlewheel.

I had determined that it was the pickup that was the problem, because both the analogue and digital speedometers were not registering any readings. I followed the testing procedures in the service manual as well as stated in this forum, the voltage range sensed while the paddlewheel was spinning was very narrow.

 

[Martin418]

Here;s a schematic of the internals of the sensor. Depending on year, typically earlier than this, the design might differ. I use a 2.2k resistor in series with an LED to limit current from a 12V source for bench testing. The LED flashes as the paddle wheel is spun.


View attachment 41832

Thanks for circuit!

 

[etemplet]

I have yet to get the sensor off the bottom of the ski without wrecking some of the bolts.

@Sportster-2001-951C-Stock - would you be interested in selling a tester?

 

[Martin418]

I have yet to get the sensor off the bottom of the ski without wrecking some of the bolts.

@Sportster-2001-951C-Stock - would you be interested in selling a tester?

I can rebuild the speed sensor if needed.

 

[etemplet]

I can only imagine the stuff I'd dream up if I knew electronics. I'm sure I'd enjoy a class on that kinda stuff.

 

[etemplet]

I am getting an intermittent fail on both speedos, info gauge and speedo instrument. It only works for a few seconds. I installed a used pick up and the instruments worked for the first ride but now I"m getting a sometimes reading. Help would be appreciated. Looks like I'm gonna get more into these speedometers that I want but... C'est Lavie.