Turn Signal Control Unit

[Grafilthy]

Correct me if Im wrong , I believe my 2 pix show a T.S.C.U.
Mine . off a 79 gs850 , is covered in rust and looks to be failing soon.
My question is . Is it possible to take the unit out of the equation alltogether ? And still have operable winkers ? I'd imagine its rather hard to find a GOOD replacement unit .

[chuck hahn]

Yup thats the dreaded TSCU.. There have been a few threads about retro fitting 2 flash units to the 4 wire plug. 2 of the wires run the right signal and the other 2 run the left. You take the 6 pin connector out of the circuit. They will flash but yioull not have any selfr cancelling feature if the bike has that. Basically your running each of the turn signal sides with its own flasher unit.

[sedelen]

Correct me if Im wrong , I believe my 2 pix show a T.S.C.U.
Mine . off a 79 gs850 , is covered in rust and looks to be failing soon.
My question is . Is it possible to take the unit out of the equation alltogether ? And still have operable winkers ? I'd imagine its rather hard to find a GOOD replacement unit .

If it works, congratulations! I've been through well over a dozen of those things before I found a good one. Just recently they had a sale at Boulevard Suzuki and for the price of only $188 you could get a new one, now it's $331, retails $441.
If it works, take very good care of it, put some rubber where it fits into the cavity outside the battery (isolates from shock). and make sure it's not installed upside down (will collect water, has an arrow on side).
Here's one on E-bay, odds are it won't work, but it offers free shipping!
As far as the poor condition of yours, doesn't really matter, I had some really nice ones that did not work, and some really nasty ones that worked to some degree.

http://www.ebay.com/itm/250920275715?_trksid=p3984.m1423.l2649&item=250920275715&viewitem=&sspagene=STRK:MEWAX:IT&vxp=mtr

[850 Combat]

I just bought a brandy new one on sale on Monday. Still like $170.00 though, and about $25 for a matching new relay. I hope it works.

I've tried numerous used ones and changed out the speedo a couple times.

[Normk]

I'm wondering if someone who is more conversant with electronics could suggest either some off the shelf or circuit design which could be adapted?

The controller uses an AC signal from the speedo to activate a timer and stops the timer when the signal is either not present or below a certain frequency....must be above a certain frequency as it is reported to operate above 10 mph (if memory...)

This problem doesn't appear to be rocket science although that is always easy to say when one does not know how to accomplish the task.

An option might be to simply place a timer in line and to dispense with the speed signal aspect if that were too much complication. Since there are people here who know the answers, could someone please outline the complexity of the issue, just for interest sake?

[rustybronco]

Norm, A circuit already has been designed to replace the original with, including the artwork for the circuit board.

http://thegsresources.com/_forum/showthread.php?p=871063#post871063

I wish He had the time to make a write up available, unfortunately there are other issues a bit more pressing in His life at the moment.

[Normk]

Interesting thread, thanks! If/when my controller quits, I will almost certainly convert the system to manual to that the signals remain on until cancelled as am far too cheap to spend anything like the asking prices for these controllers. It does appear from the discussion between individuals who understand the problems, that the cost to make is much higher than imagined but that's one reason for asking.

There used to be several self cancelling systems on bikes, way back then, but these have seemingly disappeared from the OEM market. I wonder why? Cost to produce seems unlikely so maybe there were some perceived liability ussues?

I recall one system which used a small solenoid to unlatch or return (can't recall) the signal switch in order to cancel. My Yamaha Vision 550 had a cancel system but can't recall

I made some replacements and some installs for bikes years ago, which used a pair of push buttons for right & left, plus a center one for cancel. The means of operation was to use latching relays for the directions and simply opened the power feed to cancel. I recall it was a very simple set-up for which the main issue was making a means of mounting the buttons. Some of these new mico switches would be avast improvement over what we had with which to work back then.

It may happen sooner than later as my controller doesn't like cold weather which may be a sign that it is failing....I sure don't like the cold and am certainly failing....

Norm, A circuit already has been designed to replace the original with, including the artwork for the circuit board.

http://thegsresources.com/_forum/showthread.php?p=871063#post871063

I wish He had the time to make a write up available, unfortunately there are other issues a bit more pressing in His life at the moment.

[rustybronco]

Norm, one could easily make up a 'manual' cancel system that uses the original left hand momentary contact switch (turn signal) using a few self latching relays in place of the factory turn signal controller.

one pulse to latch the relay and the cancel button on the switch to open pwr to the relay cancelling it.

[Normk]

That's what comes to mind as the simplist solution so must have been the strategy I used, although it was more than a decade ago....

I think that a normally closed relay connected to the cancel contact to open the circuits and the R&L sides, each with their own relay might be the way to go although haven't studied the wiring enough to be sure. I find it quite amusing that the only complex electronic device in my bike is to cancel the signal lights as ignition is breaker point, etc. I suppose the voltage regulator might be more complex but if someone were to assert that I'd have to concede.

Unless/until there is a need the solution can wait. Thanks for the consideration.


I see that the manual cancelling switch is a normally open switch on a separate circuit so would lend itself to opening a normally closed relay. I'm wondering how you propose to use it to directly open the circuit to the relay? I suppose a resistor in series with the relay winding ground circuit and applying power to the relay end of the resistor? Hmm, if that's what you propose, a lower voltage relay in that manner would be an elegant solution as it would avoid the need for the normally closed one....

Norm, one could easily make up a 'manual' cancel system that uses the original left hand momentary contact switch (turn signal) using a few self latching relays in place of the factory turn signal controller.

one pulse to latch the relay and the cancel button on the switch to open pwr to the relay cancelling it.

[Grafilthy]

Wow Sounds as if I opened a can of worms.. Ive never owned a bike with self canceling blinkers , so , that tscu coming outta the mix when it fails is not causing any sleep loss.
Thank you guys for the excellent advice I always receive here !

Graf

[Nessism]

In case someone reading this doesn't know...

The first generation TSCU is the problematic type. The signals won't flash without the unit, and the units are unreliable.

The second generation TSCU was spawned in 1980 and is both more reliable and the turn signal circuit will function even if the unit is removed entirely.

[tas850g]

I think I have one of those units that was in a box of parts I bought. However, on my '79 I dont have a place to plug it in to. My bike now has the electronic ignition but I don't know if that has anything to do with it.

Where would that plug into?

[sedelen]

I think I have one of those units that was in a box of parts I bought. However, on my '79 I dont have a place to plug it in to. My bike now has the electronic ignition but I don't know if that has anything to do with it.

Where would that plug into?

The first generation unit has two plugs, the second one plug and one ground wire. The first generation plugs into receptables that stem from the main wiring harness under the air cleaner box close to the end of the battery that's closest to the front of the bike. There is a metal cavity on the outside of the battery box on the right side the TSCU fits into. The '79 used the first generation problem prone TSCU. Don't believe it has anything to do with electronic ignition.

[Normk]

I have identified solutions/modifications for other bike's systems such as fuel pump relay replacement for a "smart" relay. These relays are common to newer bikes using electric fuel pumps which use a strategy to disable the pump unless several conditions are met. It is possible to meet these conditions by use of conventional, off the shelf, relays and some innovative wiring at a tiny fraction of the cost of the original relay.

I offer the above in support of the theory that some solution may be possible to treat with the signal cancellation unit?

As I understand the systems:
1) There are two "types" of signal cancellation system. 1970 & later?

2) The early system uses a conventional signal flasher (sometimes called a "signal flasher relay" of such but not by the trade)

3) The later system uses a unique signal flasher which may be composed of a normally closed relay and signal flasher?

4) Someone was discussing the marketing of a replacement unit at about 1/2 the cost of the Suzuki unit but this, although value for the money, exceeds the cost which many are prepared to justify.

Would someone explain the circuit operations of the later signal circuit operation?

I am intrigued regarding the 5 position switch which someone referenced. Is this simply a reflection of the fact that the switch serves other purposes or are the 5 positions involved in signals operation?

Some of these systems are unecessarily complex so we may be able to identify a solution which may fit some needs.

[850 Combat]

The 5 position switch is High / Low beam in the vertical, and signals to right and left, if I understand the question.

The controller I guess has a timer and also a signal from the speedometer. It shuts off the blinkers after a specified duration or distance travelled, whichever is longer.

They are very convenient.