wow, all that for a turnsignal!

[Nevets]

Last summer, while my bike was under warranty, I experienced some weird turn signal problems. The signals would occasionally flash fast, as if a bulb was burned out, or a wire or socket was malfunctioning. After a lot of cleaning, checking, etc, I convinced the dealer that the flasher module should be replaced under warranty. They seemed to offer little resistance to this, and also suspected this would solve the problem. Almost sounded like a symptom they had seen before.

 

In any case, things are working great now with the new module. I asked if I could keep the old one, and they said sure. I thought I’d see if I could see what was inside the module, mostly out of curiosity, and also under the slight chance I might be able to repair the old module.

 

Wow, talk about complicated! I was amazed at the amount of stuff inside of the module. It seemed very odd that the module innards were not sealed better, or potted, especially considering where the module mounts on the bike. I could see if it was mounted under a dashboard on a cage, but on a motorcycle!?!?!

 

Below are some pictures of the insides. Note the double sided pcb with surface mount parts. About 55 components of varying type with even an eight bit processor and memory!

 

The outside plastic case of the flasher module:

 

One side of the flasher module PCB with microprocessor and high power driver transistors:

 

The other side of the flasher module PCB with a lot of miscellaneous transistors, op amps, resistors and caps.:

 

So, being that my eyesight is not what it used to be, and I have better things to do (at least I tell myself), I have not tried to diagnose why the old module failed. Just goes to show, that there is a lot going on in even “simple” devices. Now, if we could just reprogram the microprocessor for self canceling turn signals…..

[TMH]

Now, if we could just reprogram the microprocessor for self canceling turn signals…..

You can! It is called the Kisan SignalMinder. And it turns all 4 of your TS bulbs into running lights as well for better conspicuity (legal in 48 states, I believe).

 

Tom

[Nevets]

You can! It is called the Kisan SignalMinder.....

Yea, I know. But the point is that it's a shame to have to do that when the hardware (microprocessor, etc) is already in place in the existing module. After all, "it's just a little software".

[kelly1005]

How did they make lights flash in vehicles before? According to this page http://inventors.about.com/library/inventors/blcar.htm they had electric turn signals in 1938 and I'm pretty sure they had no ICs to do it with. If it takes 55 components to do it with ICs, how many descrete components would it take? 1000s?

 

Why is everything so complicated these days?

 

Hey you damn kids, get off my lawn! (just practicing, as I'm obviously getting old)

[TMH]

Now all of you repeat after me:

 

"Computers make our lives easier..."

 

 

Well, at least more fun, because they allow us to access BMWSportTouring.com!

Tom

[Nevets]

how many descrete components would it take? 1000s?

 

My guess is that in the microprocessor alone (not including the other 54 components) based on the 105 page data sheet from STMicroelectronics, you are talking at least 5,000 transistors. A few of the microprocessor features:

8-BIT MCUs WITH A/D CONVERTER, TWO TIMERS, OSCILLATOR SAFEGUARD & SAFE RESET

 

Memories

* 1K, 2K or 4K bytes Program memory (OTP, EPROM, FASTROM or ROM) with read-out protection

* 64 bytes RAM

 

Clock, Reset and Supply Management

* Enhanced reset system

* Low Voltage Detector (LVD) for Safe Reset

* Clock sources: crystal/ceramic resonator or RC network, external clock, backup oscillator (LFAO)

* Oscillator Safeguard (OSG)

* 2 Power Saving Modes: Wait and Stop

 

Interrupt Management

* 4 interrupt vectors plus NMI and RESET

* 12 external interrupt lines (on 2 vectors)

 

12 I/O Ports

* 12 multifunctional bidirectional I/O lines

* 8 alternate function lines

* 4 high sink outputs (20mA)

 

2 Timers

* Configurable watchdog timer

* 8-bit timer/counter with a 7-bit prescaler

 

1 Analog peripheral

* 8-bit ADC with 8 input channels

 

Instruction Set

* 8-bit data manipulation

* 40 basic instructions

* 9 addressing modes

* Bit manipulation

 

I guess one function that may require all of this extra horsepower – it also runs the 4-way flashers!

[BobFV1]

I had a 1983 Gold Wing which had factory self-cancelling turn signals with three mechanical inputs. It worked fine for years and years - used steering head angle, time, and some other input. No microprocessor, just solid old-fashioned engineering!

[BeniciaRT_GT]

I had a 1983 Gold Wing which had factory self-cancelling turn signals with three mechanical inputs. It worked fine for years and years - used steering head angle, time, and some other input. No microprocessor, just solid old-fashioned engineering!

 

Yea, but it weighed more and was less reliable

 

[nrp]

By googleing just those major part numbers you can get insight into what all the major blobs do, such that you might be able to decode what's wrong. It is rare that this silicon stuff fails unless it is grossly abused. Caps are always suspect though.

 

Some elements on the board have the look of being hand soldered.

[Nevets]

By googleing just those major part numbers you can get insight into what all the major blobs do, such that you might be able to decode what's wrong. It is rare that this silicon stuff fails unless it is grossly abused. Caps are always suspect though.

 

Some elements on the board have the look of being hand soldered.

 

With almost 30 years in electronics, the last 12 designing electronic test equipment, I know of what you speak. Due to the lack of potting and partial exposure to the elements, almost any of the components could be suspect. Since the unit was partially working, component drift (like from a cap) seems likely. Also solder joint cracks or electromigration effects could contribute to it’s symptoms. No obvious visual faults detected.

 

However, for something like this, I consider life is too short to worry about repairing it. Also, in this case the warranty makes me not inclined to diagnose the problem. I’ll just clutter up my garage with a dead unit as a reminder of how complex reality is.

 

If someone wanted to keep the next one from failing, you might consider sealing the plastic box with a little silicone caulk. Might help, can’t hurt…