Change LED in Suzuki monitor gauge.

[Fabbe2]

During my engine testing I discovered that the LED for the rev limiter in the Suzuki monitor gauge was broken. Here are some hints how to replace a damaged LED on this unit:



OK i did not expect it to have LEDs but that explains the not user friendly construction.

Looking for a way in I discovered a small notch at the bottom. Carefully getting into it with a carpet knife did remove most of the glue and I managed to open the can without bigger damage:



Inside you'll find 2 circuit boards attached with 2 screws. The lower one holding the LEDs and resistors, the higher one holding the elements for the oil level delay:



A quick check on the LEDs showed to broken lamps. Rev limit and water temp.

No I had to decide if soldering directly on the circuit board or just to take the LED a bit higher up. I decided for the later version because I thought of further replacements if not using the right LED.

So I cut out the damaged LED:



Meanwhile I was checking on a good spare part, knowing the resistors on the upper circuit board to have 474 ohms. Found 5mm LEDs, red, 8'000mcd with 30? which come close to the original ones during testing.

So I cut the connectors to the right length and clamped it to the connections left from the old LED. Polarity was written on the board, anode down, cathode up.

 

[Fabbe2]

Re: Change LED in Suzuki monitor gauge.

Finally soldering the new LED in place. Not looking professional but working perfect:



Color and intensity seems to be a good choice.

When it comes to the wiring here are the connections:



grey- ignition +
black- ground
pink/blue- oil flow switch
red- rev limit
red yellow, gren and blue- oil level switch
gren yellow- overheat waring.

Watch out testing the LEDs, specially the rev limit as it is not connected with a resistor but gets + directly from the CDI. The other ones can be tested by connecting ground to each light while ignition grey and ground black are connected and ignition switch is on.

 

[TerryMSU]

Re: Change LED in Suzuki monitor gauge.

As an electronic engineer with a good bit of experience, I was curious to see how things turned out for you, so I took a look at your final assembly. I think you did a pretty good job. By not unsoldering the LED, you saved yourself a lot of risk. That particular type of circuit board (called KEM-1) is very difficult to repair. The circuitry will peel off the board very easily, which is not a good thing. Even with good professional tools I would have taken the same approach you did. The only cautions that I would give to anyone trying the same repair are as follows... 1. LEDs are polarity sensitive. Put them in backwards and they will not light. It is also possible that they may be damaged as well if they are put in backwards. 2. Be very cautious when soldering this sort of thing. The board and parts may be damaged by excess heat and also but static electricity.

TerryMSU

 

[Fabbe2]

Re: Change LED in Suzuki monitor gauge.

As an electronic engineer with a good bit of experience, I was curious to see how things turned out for you, so I took a look at your final assembly. I think you did a pretty good job. By not unsoldering the LED, you saved yourself a lot of risk. That particular type of circuit board (called KEM-1) is very difficult to repair. The circuitry will peel off the board very easily, which is not a good thing. Even with good professional tools I would have taken the same approach you did. The only cautions that I would give to anyone trying the same repair are as follows... 1. LEDs are polarity sensitive. Put them in backwards and they will not light. It is also possible that they may be damaged as well if they are put in backwards. 2. Be very cautious when soldering this sort of thing. The board and parts may be damaged by excess heat and also but static electricity.

TerryMSU

Thanks! You are totally right these are sensitive units and easy to destroy. But with a little caution and good preparation it's possible to do.
/Fabbe