Yamaha tachograf problems please help!

[fairdeal]

something like this should suffice (typically 1/8 or 1/4 watt)

[boscoe99]

hello, i belive was not so difficult to connect a tach to engine, but is, so .....
need last hand help, i have the gauge and the small cable who connect to this, and the engine, what should buy to make this tach function well, i don't want to expand the network to others gauges - i wont just this tach to indicate and that's all. it is a must have - the multi hub ? or to simplify the network it is necesary just a special cable for single tach and single engine? i found in google a lot of possible combinations to make this and now i am confused.
thanks a lot!
good forum and good advice from users - good job!!!http://www.yamahaoutboardparts.com/i...ons/icon14.gif

It is not difficult at all. You simply need the correct parts. It can't be any easier.

It can be cheaper but it won't be easier.

[boscoe99]

Far be it from me to tell anyone to modify his Yamaha stuff. But, I have done the following and it worked for me.

Simple quarter watt resistor from Radio Shack. Wire insulation cut back to solder the resistor between the blue wire and the white wire. Wire insulation cut back to solder power and ground leads from the key switch.

[pstephens46]

It is not necessary to use the Yamaha multi hub - or any brand of specialized NMEA 2000 wiring/devices -

(at least probably not on the minimal "network" you desire)

but you DO have to mimic the circuitry that those devices would automatically provide!

Here is the pictorial form of what you need using "standard NMEA 2000 parts"





I will try to find /sketch the simple schematic this represents

What is the purpose of these resistors? Do they somehow focus or contain the signal?

[fairdeal]

What is the purpose of these resistors? Do they somehow focus or contain the signal?

"Terminating resistors"?
I have no understanding of it; only a vague memory that it perhaps stops "reflections"

Something like that great Walter Matthau movie where the subway car ran full speed into the South Ferry station...



I am curious to know why Boscoe got the idea to connect up a Command Link gauge with just one resistor "in the middle".

[boscoe99]

"Terminating resistors"?
I have no understanding of it; only a vague memory that it perhaps stops "reflections"

Something like that great Walter Matthau movie where the subway car ran full speed into the South Ferry station...



I am curious to know why Boscoe got the idea to connect up a Command Link gauge with just one resistor "in the middle".

Well, I got to thinking that when two resistors are in parallel in a circuit then the total resistance on the circuit is one-half of the value of the resistors (assumes they both have the same value). So I measured a CL set up with two end line 120 ohm resistors installed and sure enough when the blue wire was measured to the white wire there was a resistance of 60 ohms.

So I said, what the hell let's just install a 60 ohm resistor between the blue wire and the white wire and see what happens. Connected a CL tach at one end of the harness and a motor at the other end. Added electrical power to light up the gauge. All of a sudden engine data appeared on the CL tachometer.

I turned this into a test rig and gave it to a Yamaha dealer. He was loaning it to folks who had early model motors that thought they might have CL capability. If their engine supplied engine data to the tachometer using the test rig they would then buy what they needed to do the full set up. If their engine did not supply data then they knew what the situation was.

Being the cheap barstard that I are, it was a hellava lot cheaper to use one Radio Shack resistor than two Yamaha end line resistors, to which I would have had to add a hub and some more expensive Yamaha harnesses.

[pubertfester]

boscoe99 and fairdial you are my heroes. yes it working.!!!!
put the rezistor (one) to the wire and it working good..........

But ( i hate this but) .....it work with my small cable (half a meter), after put on the long cable 3 meter it is dead again.. so a last help ( i am so close ) what should i do? should i put another rezistor?
my long cable is the same like short cable ( was working) just 3 meters long same connectors .
thanks in advance!

[pubertfester]

Long cable is like the small cable with rezistor,the difference is longer .

[fairdeal]

boscoe99 and fairdial you are my heroes. yes it working.!!!!
put the rezistor (one) to the wire and it working good..........

But ( i hate this but) .....it work with my small cable (half a meter), after put on the long cable 3 meter it is dead again.. so a last help ( i am so close ) what should i do? should i put another rezistor?
my long cable is the same like short cable ( was working) just 3 meters long same connectors .
thanks in advance!

Long cable is like the small cable with rezistor,the difference is longer .

Interesting. Well, Boscoe can tell us the length of the harness on his "test rig" -

from the description, I'm guessing it may have been less than a meter.

I would try the two 120 ohm resistors, one "at each end". Just as it would be on a "real" NMEA backbone - which according to the guidance, can be up to 100 meters long.

[boscoe99]

Interesting. Well, Boscoe can tell us the length of the harness on his "test rig" -

from the description, I'm guessing it may have been less than a meter.

I would try the two 120 ohm resistors, one "at each end". Just as it would be on a "real" NMEA backbone - which according to the guidance, can be up to 100 meters long.

That is what I would try.

My cable was only a few feet long.

[pubertfester]

Hy, bad news in my zone, i put rezistor120 ohm near the engine connector and otherone near gauge connector , and gauge refusing to work. Please some opinions? I try the same scheme with 60 ohm rezistors and nothing. Thanks. Wait some ideas.

[pubertfester]

I believe this is the circuit you need to create a "network" between the engine and guage

so you will need wire AND 2 resistors

(I don't "off hand" know the Command Link guage pin identification as to which equate to data white, data blue, 12v+, and ground)

Boscoe - what do you think of this?

This is the scheme of what i try today with 120ohm rezistors, and after, i change the rezistors with 60ohm.

[pubertfester]

Could be the cable ? it is from copper wires (not rigid)with 1,5 mm diameter it is a common wire like the lights in the house.

[boscoe99]

This is the scheme of what i try today with 120ohm rezistors, and after, i change the rezistors with 60ohm.

Don't think that will work. The gauge needs to be between the end line resistors. That is why they are called end line resistors.

[pubertfester]

I should do the same to the engine side? Like in your diagrame in right side? Or exactly in your diagrame