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Tachometer Help From MouseWheels?
Posted: Sat Feb 22, 2014 1:07 pm
by Wheelman-111
Greetings:
For no apparent reason, a few months ago I sprung for a Chinese-made Tachometer on fEeBaY. I guess I was anticipating the day my beloved but unlit and slow-refreshing TinyTach battery would finally give out. Anyway, this thing was cheap.
- SpeedoBox.jpg (141.38 KiB) Viewed 18863 times
And it looked pretty good,
- SpeedoFront.jpg (166.94 KiB) Viewed 18863 times
although I'll need to enlarge the hole in the splash guard where my analog temp gauge used to live. So while I had the seat bucket out for mounting the Flash 7 engine, I got some wire and began trying to figure out how it hooks up. Of course it didn't come with instructions, but I already knew from snowmobile tach installation that you use the low-tension wires at the coil.
- SpeedoBack.jpg (148.5 KiB) Viewed 18863 times
I quickly confirmed that the blue and orange paired wires are for night lighting. The other three wires shown are Black, Black/Yellow, and Green. After trying every possible combination and permutation of grounding the green, and both sides of the coil with each of the three wires, I couldn't get the needle to so much as quiver. On a whim, I connected the black and black/yellow together and touched those to the coil with the green grounded and yes, the tach needle indicated RPM, albeit really slow because of overdamping about 15% low when compared with TinyTach.
So is it worth installing this thing, d'ya think? Is there a combination I haven't tried?? Any help from anyone is welcome, but I know Mighty Mr. Mouse likes an electronic challenge. By the way, those wacky folks at YongLong Motorcycles have Photoshopped ane "graced" their box with the most frightening Triumph Rocket 3 motorcycle image ever imagined.
- speedoBike.jpg (165.6 KiB) Viewed 18863 times
I for one am grateful they assured me that the Kege parts are in fact "Genuine".
Re: Tachometer Help From MouseWheels?
Posted: Sat Feb 22, 2014 6:14 pm
by mousewheels
Good work from zero diagram - What's KEGE thinking, they should supply a complete diagram:?
Link to KEGE - but a different model
Hard to say for certain, electrical folks implement differently - as long as it works
. Ignition pickup is required for sure. Re: Black wire --- If KEGE is consistent, the Black lead would be +12v rather than LV ignition side. That makes sense in when compared with the Sun tach we were modifying awhile back. It needed +12v, gnd and a source of RPM pickup.
== From KEGE site ==
13K RPM BACKLIGHT ODOMETER SPEEDOMETER TACHOMETER MOTORCYCLE REV COUNTER/TACHO
1. Easy to install
2. High capacity and practical
3. Fits for motorcycle (4 stroke)
4. Material:Stainless Steel
5. 0-13000RPM Measurement
6. Internal Night light, black(-) and red(+) long lines for LED light, DC 12V
Black short line lock positive electrode
Green short line lock negative electrode
Yellow line contacts signal´╝îand some models need to attach high voltage signal line
7. Shape:circle
8. Size:60(D)mm*55(H)mm
9. Tachometer unit: RPM
Wire connection:
long Red light +
long Black light -
Short Black power/ignition lock +
Short Green Ground
Short Yellow engine signal line
Quantity: 1pcs
Re: Tachometer Help From MouseWheels?
Posted: Mon Mar 03, 2014 8:20 am
by Wheelman-111
Greetings:
As noted in Flash 7 I finally got the backlight to come on. Both a bad bulb and a bad Wheelman crimp made it a Mystery for a while.
I couldn't get the tach needle to move at all until I connected the short Black and short Black/Yellow together and hooked the pair up to the coil LV side. Now it reads, but almost exactly 2/3 of the RPM the TinyTach displays. I wonder what the instructions mean by "...and some models need to attach high voltage signal line."?
Suggestions, Mr. Mouse?
Re: Tachometer Help From MouseWheels?
Posted: Tue Mar 04, 2014 7:02 am
by mousewheels
I couldn't get the tach needle to move at all until I connected the short Black and short Black/Yellow together and hooked the pair up to the coil LV side. Now it reads, but almost exactly 2/3 of the RPM the TinyTach displays
Not sure why it's measuring low. Signal at coil LV side (ignition primary) should be easy for the tach to read.
Was there no needle movement with solid black tied to +12v AND yellow/black on the coil LV side?
I wonder what the instructions mean by "...and some models need to attach high voltage signal line."?
Poor translators for sure. From the wire insulation, they can't mean to directly connect to the coil secondary. Wonder if some models of tach implement an inductive style plug lead pickup?
One thing for sure - the tach is affordable. I have ordered one from eBay for a tear down and test. Should be here in 2-4wks.
Re: Tachometer Help From MouseWheels?
Posted: Tue Mar 04, 2014 8:30 am
by Wheelman-111
Greetings:
Yes, tried all the combinations. The only movement was when I tied the yellow/black and black together. Weird. Yes it was cheap. The makers saved an awful lot on translators, instructions, and "images" for their box I guess. (I see that Rocket 3 in my nightmares.)
I really appreciate your Elecspertise, Mouse. Can't wait until you tear into it. Beware though: the outer bezel holding the glass lens is rolled (like a food container can) onto the body and won't come off without a fight.
Re: Tachometer Help From MouseWheels?
Posted: Tue Mar 04, 2014 8:35 am
by swimmingfree
i wood of pull the back off and took a photo of it ...
swimmingfree
Re: Tachometer Help From MouseWheels?
Posted: Tue Mar 04, 2014 9:38 am
by Wheelman-111
Greetings:
SwimmingFree sez:
i wood have pulled the back off and taken a photo of it ...
That's just what I said. It won't come apart without a can-opener. It seems our Inscrutable Asian Friends decided to crimp the bezel around the body instead of relying on the screws alone. There's a tool for uncramping that thing, but I don't own one.
Re: Tachometer Help From MouseWheels?
Posted: Thu Mar 27, 2014 4:23 am
by mousewheels
Wheelman-111 - We might have confirmed you got a bad tach. However did you test using the Ignition Pulse generator signal (spark trigger coil in below text)? Looks promising between comparison of scope pics + rejection of positive going pulses. I'll confirm on a scooter soon.
------------------- Progress Detail --------------------
-- Flakey seller
One tach was ordered but two arrived. The auction said "New" yet one tach has been installed with cut/soldered wires. The other has an issue, and will not go to zero. All ended ok - the returned tach is functional, and there's a junker to cut apart
- Returned_plus_defective_tach.jpg (159.14 KiB) Viewed 18717 times
--- Bench test connections to tach:
Black: +12v
Green: Ground
Black/Yellow: To signal generator
Orange: +12v (back light power)
Blue: Ground (back light return)
--- Tach Drive signal profiling
0 to 5v pulse-- Fail, zero reading
0 to +12v pulse -- Fail, zero reading
0 to -4v pulse -- Pass, reliable tach reading ---> That's good, scooter's spark trigger is also a negative going pulse
0 to -12v pulse -- Pass, reliable tach reading --> Max signal generator output
-- Tach calibration check and oscilloscope pics
- KEGE_Tach_drive_and_calibration_test.jpg (271.04 KiB) Viewed 18717 times
-- What's next?
Tach will be tested on a scooter per diagram below.
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Re: Tachometer Help From MouseWheels?
Posted: Thu Mar 27, 2014 8:25 am
by Wheelman-111
Greetings:
Quoth MouseWheels:
Flakey seller
One tach was ordered but two arrived. The auction said "New" yet one tach has been installed with cut/soldered wires. The other has an issue, and will not go to zero.
"Flakey" is apt. Can you believe these people have nukes? It's OK, one detonates on command, the other won't quite shut off and the wires are a bit frayed. We'll send you both.
I guess mine's one of the iffy ones. I paid attention as I randomly tried to sort this thing out, and couldn't see the needle respond at all unless I connected the wires you call +12V and Signal Source together at the low-voltage side of the coil. Mine reads now, but only 50% - almost exactly - of the true RPM as stated by TinyTach. For the Money, I should order 2 or 3 more and maybe get one good one?
Yours seems fine - although the 33% error below 4K would be unacceptable on any other application. Thanks for the hard work and SpreadSheet Skee-yulls.
Re: Tachometer Help From MouseWheels?
Posted: Thu Mar 27, 2014 2:45 pm
by Dio89Elite
as always mrmousewheels, awesome job!
you rock!
Re: Tachometer Help From MouseWheels?
Posted: Sun Mar 30, 2014 10:53 pm
by mousewheels
Thanks gang!
--- Update
1) Marked up a wiring diagram and service manual pic.
2) Sticky meter taken apart for pics and bind reduced - it's arguably now working
3) Tachs tested on my '98 Elite. Tachs trigger reliably, track a Trail Tech reading (with expected accuracy variances)
-- Wiring diagram
Here's mark-ups showing connections used in the following testing:
It's likely possible to make connections w/o removing plastics.
- Tach_Connection.jpg (55.04 KiB) Viewed 18675 times
-- Tach Disassembly
As Wheelman-111 pointed out, the tach assembly is not meant to be easily disassembled. The bezel ring is pretty thin, it's rolled edge gave way to slow prying a couple trips around.
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This view of inside shows why the backlight is un-evenly lit. The PCB and meter assembly are in the way
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The meter movement is a moving coil design. In the large pic, the meter is at about 5k, pic at the right side shows the coil position at 0 RPM. Bottom right pic shows the ring magnet which with pole piece.
There are two opposing 'hair springs'. Rear spring winds up as the tach advances. Front spring unwinds as the meter advances. I believe the front spring's purpose is balance (counter) the rear spring at '0' as there is no mechanical stop at 0 rpm.
- KEGE_interior_coil_and_return_springs.JPG (252.98 KiB) Viewed 18675 times
Electronics -
Brains of the tach are within "ICF CP1005". Sadly, attempts at 'net searches found no useful datasheet. To the left of the chip there is a trim pot assumed to be for calibration purposes.
- KEGE_interior_PCB.JPG (112.35 KiB) Viewed 18675 times
Re: Tachometer Help From MouseWheels?
Posted: Sun Mar 30, 2014 11:12 pm
by mousewheels
-- Sticky tach
The tach which would not return to zero was found to have a bind between the front spring and the plastic cup in front. The spring itself is damaged, and is no longer flat. The bind was reduced by not completely eliminated by sliding the plastic cup toward the meter face *and* slight bending of the spring near where it is soldered.
- Damaged_Hair_Spring.jpg (116.5 KiB) Viewed 18671 times
-- On scooter testing
Purpose was to verify the selected pickup location at the spark trigger coil works. A Trail Tech tach was used to verify the KEGE tachs were tracking RPM reliably. Pic shows KEGE tach connection to CDI Blue/Yellow wire. Right pic shows the TT tach using a 'clip on' pickup also being tested -
see tachometer mod thread for detail - Link
- Tach_Pickup_Locations.jpg (130.49 KiB) Viewed 18673 times
-- Results
Electrical signal definitions appear successful. Both KEGE meters track the TT tach, with expected accuracy variation. The sticky KEGE tach reads low compared to the other, reasonable, since there remains a bind within the movement.
- In_Bike_Testing.jpg (231.68 KiB) Viewed 18673 times
Re: Tachometer Help From MouseWheels?
Posted: Mon Mar 31, 2014 9:35 am
by noiseguy
Nice work.
Did you try playing with the pot to see whether it changes 0 or slope?
Re: Tachometer Help From MouseWheels?
Posted: Mon Mar 31, 2014 9:55 am
by Wheelman-111
Greetings:
Mouse is Master of Meterage. Is there a chance I can recalibrate mine? This of course assumes I have the patience and dexterity to pop the can lid off without mangling contents within. I'm guessing the "Trim" isn't going to compensate for the 50% value I'm seeing, but maybe?
Re: Tachometer Help From MouseWheels?
Posted: Mon Mar 31, 2014 9:45 pm
by noiseguy
This guys selling cp1005 chips 10 for $11.
http://m.ebay.com/itm/320610033704?nav=SEARCH
Maybe he has a datasheet?
Here we go... Its an optocoupler. That makes sense in this usage... But would also imply that the whole thing is a simple circuit. No brains.
http://www.alibaba.com/product-detail/P ... 69049.html
Thought manufacturer was ICF. Perhaps ICP... And that means generic in Chinese?
http://cp1005.ic.icpdf.com