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1Back to top Go down   How does the gear position indicator work? Empty How does the gear position indicator work? on Mon Dec 30, 2013 12:08 pm

defied

defied
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active member
I picked up the Acewll Speedo, and was working on the three relay mod to determine when the bike is in neutral.

There seems to be no voltage coming down the line from any of the wires whenever I move the gears around.

So my question is, is there supposed to be voltage down the line(s) when a gear is selected?
If so, what is the part number(s) if I need to replace the indicator?

Thanks,
D

    

duck

duck
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It's all based on which wires are grounded.  There is no power to or from the GPI switch.

http://home.comcast.net/~smithduck/bmw/13tech/gpiemulate/gpiemulate.htm


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

robmack

robmack
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The switch has a common ground connection to the wiper. It selectively grounds one or more of the remaining wires to indicate the gear number, depending on the rotational position of the wiper.  Neutral is the position where all three wires are grounded. You will not measure any voltage at the switch; only conductivity to ground.

In Duck's schematic,  you'll notice that a source of +12V is switched through the coils of the relays.

To get really technical, the switch is implementing an inverse binary coded decimal logical truth table.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

defied

defied
active member
active member
Hmmm. I wonder why it's not working? Maybe I somehow cooked a relay. I hate radio shack pcb's.

D

    

duck

duck
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Can you post up a pic of one of your relays and/or give us the info printed on it?  That could probably be used to look up a datasheet for it and determine the pinout for it to make sure that you're connecting the correct wires to the correct terminals.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

defied

defied
active member
active member

    

robmack

robmack
Life time member
Life time member
In that link, you'll notice that Rafael annotated the relay pins with the ISO numbering.  The coils are pins 85 and 86. The contacts are 30 (common) and 87.

Are you certain you got the 12V versions of that relay?  They are also manufactured in 3V and 24V versions.

First, check your soldering for accidental bridging and open circuits using a magnifying glass and good task lighting.  The pins on these PCB relays are tiny, spaced at 0.1"  and if you are using 18 AWG wires from the TGPI, they could accidentally cause bridging. I use 30 AWG for interconnecting PCB relays.  Did you use a perf board or try to solder the pins directly using Duck's technique?  The latter requires care (eg. tinning the wires before soldering).

Next trace the wiring to see that it matched the schematic.  Make sure you haven't accidentally miswired.

If all the connections look OK and the wire tracing looks correct, then test the coils for continuity using a multimeter.  The resistance should be in the 100-200 ohm range.  Open circuit will indicate that you burn a coil.  Short circuit will indicate an accidental bridge.  Also check continuity between common and the N.O. pin (#87); it should be infinite ohms.

You could test the relays by applying +12V to the coils to hear for contacts moving.  That could give you assurance that the relays are mechanically sound.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

defied

defied
active member
active member
I will throw on the MM.

They were clicking originally, but after a few configs, they stopped, which is why I was curious as to if I broke something on the bike. 0]

I will also toss the 12v power (Yes, they are the 12v versions) on them individually to see if they click.

I may end up desoldering them, getting a better, cleaner perf board, and rebuild it, if they all work.

D

    

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