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Discussion Starter #1 (Edited)
Trying to determine if the damage I did is fixable or not. Thanks in advance for any insights.

As a first step into my voyage of diagnosing why my low fuel indicator isn't working, I thought I should first verify that the LED lights up (I know, LEDs rarely every burn out, but still, I thought I should rule it out).

I took the dash apart, and figured I could jumper from the battery to the anode (+) and cathode (-) just under the LED, but stupidly didn't think to determine which side was which. It flashed a faint orange and then went dead with a faint "zap" sound. No visible damage to the LED, though.

Since I wasn't sure if that fuel LED was good to begin with, I decided I needed a control group. If I did damage, it's done, and I might as well try and get an accurate diagnosis. So I repeated the process on the turn signal LED, which I knew to be functioning, and got the same flash/zap.

Perhaps that means I reversed the polarity and killed the LEDs themselves, or going straight from the battery to the LED was bad?

To determine if I just fried those individual LEDs, or the whole panel, I reconnected it to the bike and turned the key on. Everything else lit up as expected, but the turn signal LED no longer functions. I disconnected the dash and removed from the bike again.

Testing for continuity, I get the same reading from those LEDs as I do from others that I know to be working.

Now I'm stumped. What I'm looking for is a way to isolate variables and test them. Can I, say, test the functionality of the fuel LED by jumpering the pin of the side stand LED on the 20-pin connector, turn the ignition on, and see if the LED lights up instead of the side stand LED?

UPDATE: I'm thinking something like the hi-beam or turn signal pin would be a more reliable control group. I think the sidestand isn't a simple "on/off" voltage variable since it's part of a larger system or logic tests that determine whether or not you can start the bike (neutral, clutch, side stand, etc)

To test that, when I look at the diagram, are those pins labelled as if I'm looking at the connection on the back of the instrument panel, or the connector from the wiring harness? I thought I could just locate the black wire coming out of the connector to determine which corner was the GND and that would tell me how the diagram in the manual is oriented, but there's no black wire.

UPDATE: I verified that the diagram is referring to the connector on the back of the instrument panel, not the connector on the wiring harness. See post #13 for photo and description
 

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Can't offer any good news I'm afraid, if you directly connected 12v across the LED pins on the circuit board or at the connector you have blown the LED's by either reverse voltage breakdown or over volt & current.
It would be very hard to figure out which is the anode and cathode when its mounted to a circuit board unless there's some sort of screen print on the board.
They typically only have 1.5v~3.3v forward voltage and need a resistor in series with the voltage supply see LED Resistor Calculator
Circuits like these have the sensor ground the LED to activate it, most FI bikes have the level indicator on the side of the fuel pump and it's capacitive introducing a few more components into the circuit.

Testing the continuity will give non conclusive readings as there would be a bunch of other components that the test current could flow through, did you use the resistance setting on your multi meter or the diode test.

Can you post up a picture of the dash circuit board. It could be fixable with a bit of surface mount soldering and a couple of LED's from RS or whatever the US equivalent electronics supplier is.
 

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Discussion Starter #3
Can't offer any good news I'm afraid...It could be fixable with a bit of surface mount soldering and a couple of LED's
That is actually pretty good news, if that's the case.

How can I verify that it's only the LED's that are toast, and not something else on the circuitboard?

When getting replacements, how can I determine the spec on these so that I can make sure I'm getting ones with matching voltage?
 

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Finding the same LED without having a lot of test equipment will be pretty hard.
At this point what is your electronics skill level.
I would be ringing round a few instrument repair places and getting quotes even if they want $200 it's cheaper than a new dash from Startwin @ 600 euro + the wait time from Italia.
Give them the circuit diagram from the manual and they might suggest how to trouble shoot the fuel sender which was probably the cause of the initial problem. I had a quick skim through Brutale 910 S manual from Donsy's site and the sender appears to be a separate component.
 

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Discussion Starter #5
I saw a couple dash unit replacements on ebay for $250, but they're both in Ukraine. I figure that's my worst case scenario. Shipping time isn't a problem; the bike will operate fine, these indicator lights just won't work.

I have beginner electronics skill, but I've been wanting to learn and this is a good project for me to do so since the stakes are relatively low/the damage is already done. I also have a good friend that's an aerospace engineer to use as my lifeline as I fumble through things.

If you have electronics experience, please advise if there are pitfalls to my plan: heat up the solder on the back side and remove the two 2 burnt LEDs + one that I know to be good. With the one that is good, I can multimeter diode test it to determine the polarity and which way they are oriented onto the board (the telltale is usually that the positive lead is longer, but the leads on these are the same length). Then I'll take all 3 to Fry's, a giant electronics store we have out here in SoCal, that should have plenty of LED options to which I can compare. Then I'll solder them all back in place

diagnosing the low fuel light not working is a separate dilemma. I'll be testing the sensor and checking connections on that, but am not worried about trying to solve that simultaneously with fixing the dash LEDs
 

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?

Chris;
Just went this on my Brutale......no low fuel light or erratic operaation......light comes on run out of gas a mile later
on a failed sending unit

the connections on the plug
#1 gold wire to fuel pump +
#2 silver ground
#3 shows weak continuity to #2 & #4
#4 same as #3

makes no sense

changed sending unit low fuel light works

If anyone needs to borrow a 36mm socket with a slot for the wire, to remove the sending unit PM me.....
just pay the postage

:wink2:
 

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I saw a couple dash unit replacements on ebay for $250, but they're both in Ukraine. I figure that's my worst case scenario. Shipping time isn't a problem; the bike will operate fine, these indicator lights just won't work.

I have beginner electronics skill, but I've been wanting to learn and this is a good project for me to do so since the stakes are relatively low/the damage is already done. I also have a good friend that's an aerospace engineer to use as my lifeline as I fumble through things.
OK...
You need a soldering iron 10w~20w any bigger and it will put too much heat into the board, get some solder wick and google de soldering
If you have a single LiPo cell from a torch use that to test the LED it's round 3.7v so you cant blow the LED by reverse connecting, LED must be removed from the board when you test, Buy a few random LED's to try your technique
Most of those LED's have a resistor and capacitor in parallel with the LED so they all have the same brightness and the cap may be there to reduce flickering, you may have blown the resistor as well with you first 12v test,
check continuity of the resistor with you multimeter after you have removed the LED's, the ones I can read say 222 which is a 2k2 resistor
I don't know if all those LED's are white and the plastic face of the dash makes them appear to be different colours? or they may be individually coloured so you would need to buy amber, green, red etc. LED's for the
appropriate spots.
You could temp attach 2 short wires to the pads where the old LED's were and test connect your new LED if you have it round the wrong way it shouldn't hurt anything it just wont light up then you know which way to solder them in
permanently.
They look like 5mm LED's but these come in many lens angle, colour, brightness and current ratings, they are not marked hence making it impossible to replace like for like but you should come close just don't get any high current "ultra bright" ones.
 

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I am loving this thread! Keep the info coming!
 

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I think I would first suspect the sender unit...

My strategy would have been to test the harness side, pin outs for voltage at the connector ...Much easier than risking the instrument...

Pull the instrument connector from the back.

Check pin out 6 on the harness side from V green wire. This is the +ve feed from the low fuel sensor. You will need to do this when the fuel level is low. I think under 4 litre is the trigger point but check that in the manual.

If there is no voltage then check the sender unit connections and then the sender itself.

If there is voltage then check that the other bulbs in the loop are grounded properly so that you can eliminate poor grounding.

Then check your instrument bulb with a volt meter..



Hope you sort it : )
joe
 

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Discussion Starter #10
testing at the harness

My strategy would have been to test the harness side, pin outs for voltage at the connector ...Much easier than risking the instrument...
Yep, I know that now! My curiosity sometimes outpaces my patience and due diligence to research first. "Hey, what if I just touch these wires here? Hmm. I see. That was a bad idea."

Check pin out 6 on the harness side from V green wire.
Bear with me, I'm a beginner with electrickery, but you're describing the test that I was trying to sort out in my head how to do properly. Can you confirm I'm following you correctly?

Connect my multimeter--set to DC voltage--between pin out 6 on the harness, and a ground (which I believe is pin 20 on the harness, or I can pick some other ground on the bike), and when the bike is on/the scenario is an "on" condition for that LED, I should get a voltage reading.

This is the +ve feed from the low fuel sensor. You will need to do this when the fuel level is low. I think under 4 litre is the trigger point but check that in the manual.
How were you able to decipher which pin is the low fuel sensor? I couldn't tell from the diagram in the manual whether it is referencing the connector side or the harness side, and it actually doesn't really look like the wiring pattern on my bike at all, so I think I have to rely on wire color.

Once I get new LEDs in place, I want to check that the dash LED still functions after my original failed experiment and verify that I didn't blow a resistor or something, as Baba pointed out was possible. Since my fuel sensor system is already suspect, I want to isolate just the operation of the fuel LED on the dash against something I know works. I figure I can accomplish this by connecting a lead from the low-beam pin (since that dummy light is on all the time) on the harness side, to the fuel pin on the dash connector side, basically reassigning that "on" voltage from the low-beam LED to the fuel LED. If all is good with the dash, the low-fuel light will illuminate instead of the low-beam when I flip the key on.

To accomplish this, I need to figure out how to accurately ID the pins/wires

If there is no voltage then check the sender unit connections and then the sender itself.
Will do. I'm addressing these issues separately. As soon as I pick up a test bulb to the correct spec, I'll be performing the test for the fuel level sensor that is detailed in the manual. It specifies a 12V - 1.7W. Should be able to get one from the same place that I'll be getting some LEDs to play with. If I post anything about that, I'll do so on another thread and keep this thread focused on my process of working with the dash.
 

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Discussion Starter #11 (Edited)
LED prep and determining polarity

check continuity of the resistor with you multimeter after you have removed the LED's, the ones I can read say 222 which is a 2k2 resistor
Wow, you have a sharp eye. I can't tell with my naked eye, those things are tiny. I have a good camera that I'll take a tighter macro photo with and see if I can tell

I don't know if all those LED's are white and the plastic face of the dash makes them appear to be different colours? or they may be individually coloured so you would need to buy amber, green, red etc. LED's for the
appropriate spots.
The color comes from the LEDs. The plastic face piece that covers them are all clear windows. To practice soldering, testing things, and calculating resistance, I'm going to build a simple circuit out of a 9V battery and resistor. Then I can take my new LEDs, and any good ones I remove from the dash circuit, and plug them in to compare brightness and color.

You could temp attach 2 short wires to the pads where the old LED's were and test connect your new LED if you have it round the wrong way it shouldn't hurt anything it just wont light up then you know which way to solder them in
permanently.
I just learned 2 easy ways to tell LED polarity: on new LEDs, the + side is the longer lead. If the leads are the same size, you can look for the flat edge on the LED itself. That is the cathode (-) side. If you look at the middle photo in my post with the 3 photos of the exposed dash circuit, you can see this flat edge if you look closely at the ones that are in focus. It is the edge towards the top/outside edge of the dash (it is much more obvious in real life when you look straight down at them). You can't see the flat edge on any of them in the first photo because of the angle of the photo, the flat edge is on the back side of all the LEDs.

They look like 5mm LED's but these come in many lens angle, colour, brightness and current ratings, they are not marked hence making it impossible to replace like for like but you should come close just don't get any high current "ultra bright" ones.
Thanks for the tip! I'll avoid ultra bright. For color, I'll just determine by comparing to existing ones using the 9V circuit test I described above (the green is the only one that I need to match closely. Orange can just be whatever orange looks good to me).

Your help has been invaluable so far. Thank you.
 

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Very cool information. I just looked at your pictures again and when you see the flat spot, then you see all the flats!
 

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Discussion Starter #13
The pin diagram from the workshop manual is of the connection on the back of the instrument panel. It is not the wiring harness. I confirmed this by checking voltage at a couple of pins on the harness to locate the turn signal pin and hi-beam pin. (The diagram shoes #13 and #14 for turn signals. My #13 is open, and #14 gets voltage when either turn signal is on. This makes sense since there's only one "turn signal" LED on my dash, not separate ones for L/R). I also noticed that, once you remove the back cover from the instrument panel, you reveal the two little nubs on the sides that are in the diagram.

To test power/continuity on the wiring harness, you have to flip the diagram. I'll probably make a chart for the harness side. My head will start to hurt trying to work that out mentally

To test my instrument panel once I get replacement LED's and desolder/remove the bad ones, I'll put the new fuel LED in place and tape it so that its diodes contact the solder plates in the correct spot, then jumper port #14 on my wire harness (turn signal) to pin #6 on the panel (low fuel), and jumper the ground at 20. If my low fuel LED lights up when I operate the turn signal, that should verify that the new LEDs work and that nothing else was damaged on the board. Right?
 

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It should verify that the new LED works...but it won't tell you if the fuel level sender is working.
 

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Discussion Starter #15
It should verify that the new LED works
Awesome, that's all I'm looking for. I need to isolate the variables since my fuel sender was already suspect on one end, and I blew the LED on the other end. With this thread, I'm focusing on the process of working with the instrument panel

My fuel level sender failed the initial check outlined in the manual using a test bulb and a simple circuit straight to the battery. Once a modified socket arrives courtesy of Knurl, I'm going to pull the sender off my fuel plate and inspect/test the wiring, and see if maybe a connection is bad. I'll create a different thread detailing those [mis]adventures.
 

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That will be another fun read! Those senders are expensive!
 

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Discussion Starter #17
That will be another fun read! Those senders are expensive!
Yes, they are. Way more than they ought to be. That seems to be my culprit. I started detailing my attempt at fixing the fuel sender in THIS THREAD

Now I'm fighting a war on two fronts, but progress made or things learned on the instrument panel will get posted here
 

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Discussion Starter #18
Made a little progress this evening.

I desoldered and removed my low fuel and turn signal LEDs (the two that I know I fried). The resistors appear to be good, they're still reading at just under 1k ohms. Same readings from the resistors at the bad LEDs and the good ones.

I made a small little tester out of a 3V CR2303 battery. With this I could check all of the LEDs on the board and verify they all still light up. Everything lights up except for my two bad ones.

On to sourcing LEDs. This site looks promising: mouser.com

I want to match the originals as closely as possible because I think the dash will look bootleg if you have mismatched brightnesses or varying shades of green. These are standard 5mm dome lens, water clear, and I think it's save to guess 20mA since that's such a standard. I'll get a couple different shades of the green and orange so I can choose the best color match.

To estimate the viewing angle, I lit up one of good LEDs and held it against a white napkin, then superimposed a viewing angle chart off another website in photoshop. Looks pretty dead near a 20 degree viewing angle, to me (or at least close enough).

The one spec that I'm totally unsure about is the luminosity. I don't even know what ballpark I should be looking in, and my options range from 10 to 14,000. I emailed the company to see if they'd be willing to look at my photo of a red LED lit up from a 3V battery, and give me a ballpark estimate of what mcd range I should pick up.

I think this is gonna work out fine. If any customizers out there want to change the look of their instrument panel, swapping out the color of the LED warning lights is definitely an option to someone who can solder. That could be a subtle and unique little mod
 

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Discussion Starter #19
rev limiter LED during startup

Can someone please give me a quick check as to when the rev limiter LED (red light just to the right of your tach) turns off during initial bike startup?

I can't recall if it stays on from the moment you flip on the ignition through until you start the engine, or if it turns off after the bike runs its check and the tach sweeps up and down.

I'm going to use the rev limiter as a control group to check voltage and current delivered to the LEDs because it's on its own little board that plugs into the main board, so it'll be easy to disconnect it and test the voltage at the board and connect a meter in series to test the current
 

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Ya know, if you can easily remove the LEDs and solder in another you could have just swapped some of the known good with the non-functioning to see if it was the LED or something else (like swapping injector positions to test if an injector is causing a running problem on one cylinder).

Nayway...another great source for electronic components is Digi-Key. I have found pretty much any component I have needed there. Good prices and great service.

https://www.digikey.com/?WT.srch=1
 
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