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Unpotting a TSCU

chuck hahn

Forum LongTimer
Past Site Supporter
Dale, I know your a very busy man, but did you ever get one unpotted? Any progress on anyone making a reliable modern replacement???
 
Nope, I got most of one unpotted but never tried a second. I have the parts to make up the one I designed but I've never got around to bread boarding it up... YET.

I have one that works both right and left but doesn't self cancel now that sedelen found and sent me a fully working one for Christmas. :D
 
Was wondering..Heres an odd situation for you to ponder.

The self cancelling on the Cooley works for about the first 10 minutes of riding...then it wont cancel and i gotta flick the thumb to stop them. Whats your perception to this oddity???? And the 78 1000E never cancels so thats always the thumb to kill them.
 
The self cancelling on the Cooley works for about the first 10 minutes of riding...then it wont cancel and i gotta flick the thumb to stop them.

Every time you ride it works the first ten minutes, then quits the canceling? Park it a while and ride again later you get a new ten minutes?
 
Yeah..like it has a cracked solder connection in there..when it gets heated up it ajust enough to make it not cancel....least thats my theory.
 
name your price..i want them to work as advertised..LOL

Chuck,
A fully working one is very hard to come by, out of 20 I got from various places only two fully worked. One is on my bike and Dale got the other.

I think it is perhaps the weakest link on that otherwise great design of the GS1000, and the fact they didn't make any carb intake boots, and of course the lack of carb parts.
And at that time the '78 GS1000 was their flagship, hard to believe isn't it?
 
Actually Steve, in my mind it isn't hard to believe. It still is one good looking old standard UJM. A design that has withstood the test of time. Three brake rotors, self cancel signals, H4 headlight, full bearing crank, solid chassis and a comfortable riding position to boot.
 
Chuck,
A fully working one is very hard to come by, out of 20 I got from various places only two fully worked. One is on my bike and Dale got the other.

I think it is perhaps the weakest link on that otherwise great design of the GS1000, and the fact they didn't make any carb intake boots, and of course the lack of carb parts.
And at that time the '78 GS1000 was their flagship, hard to believe isn't it?

Which part exactly is this? Do you have a picture? How many pins?
 
Jim, It it the Turn Signal Control Unit.

Here is a flock of them...
http://www.thegsresources.com/_forum/showpost.php?p=1854660&postcount=5


Operation...

The left hand control (turn signal switch) consists of three momentary contact switches. One for left and one for the right turn and the third for manual cancel.

Pushing the turn indicator lever to either the left or right, latches the TSCU in it's respective turn mode which allows the current to flow out of the turn signal flasher (a simple bi-metallic flasher) through the the left or right TSCU's internal relays. The flashing (self cancel) will shut off the flashing when one of two conditions are met. The first is when the vehicles speed is above XX miles per hour, as sensed by the reed switch in the speedometer, AND XX seconds have passed. The second is when the operator manually cancels the unit by pushing the turn switch downward.

Pins...
I'll have to count them when I get home tonight.
 
Last edited:
Jim, It it the Turn Signal Control Unit.

It looks like this...
(picture in a moment)

OK, The ones that I have seen are either 6 or 8 pin connectors. Have you looked for a mating right angle PCB connector that will mate to the harness?

The other option is to slip the pins out of the original connector and slip them into a new shell that has a PCBA mating receptacle.

The next option is to cut the wires and crimp on another set of contacts and a whole new connector setup.

Without that it will be a pain.

Fortunately my TCSU is working fine, I just need to get the TCSU mod designed. I'm doing several at once.

An Chuck is correct, failed solder joints are a primary failure mechanism for older devices. If it was not potted it would be easy to fix. It must be a mechanically weak design since as it is potted, the potting material should take the load of the PCB and it's traces. Apparently not well enough.
 
Have you looked for a mating right angle PCB connector that will mate to the harness?
I have not.

The other option is to slip the pins out of the original connector and slip them into a new shell that has a PCBA mating receptacle.

The next option is to cut the wires and crimp on another set of contacts and a whole new connector setup.

Without that it will be a pain.
The method I would use is cutting the original harness off the old TSCU and soldering it to a replacement unit. You could also reuse the metal cover (can) and have a new plastic housing made to hold the replacement circuitry.

Fortunately my TCSU is working fine, I just need to get the TCSU mod designed. I'm doing several at once.
The second gen TSCU's are a much more durable design. Unfortunately it's operation is completely different than the 1st gen.

An Chuck is correct, failed solder joints are a primary failure mechanism for older devices. If it was not potted it would be easy to fix. It must be a mechanically weak design since as it is potted, the potting material should take the load of the PCB and it's traces. Apparently not well enough.
We don't if that's the case with this unit as it has two exposed relays under the metal 'can'.
 
No I haven't. It's just conjecture at this point.

I have 7 or 8 of these units in varying states of function. I guess I could build up a little test platform and see if I can replicate the cause and also it check to see if cooling a particular relay (component?) might cause it to start flashing again.

I'm deducing it 'could' be one of the problems with these as the relays are exposed to the atmosphere and they tend to corrode and the fact some unit's will stop operating on just one side.
 
No I haven't. It's just conjecture at this point.

I have 7 or 8 of these units in varying states of function. I guess I could build up a little test platform and see if I can replicate the cause and also it check to see if cooling a particular relay (component?) might cause it to start flashing again.

I'm deducing it 'could' be one of the problems with these as the relays are exposed to the atmosphere and they tend to corrode and the fact some unit's will stop operating on just one side.

I was just thinking that if it was primarily the relays, that were failing, something small could be inserted to replicate the relay function with a FET or two.

That would keep all of the form and function the same.

We can keep playing 29 questions, which a picture would help.........

Are the entry wires/solder balls exposed inside of the device? How much room is inside?
 
I was just thinking that if it was primarily the relays, that were failing, something small could be inserted to replicate the relay function with a FET or two.

That would keep all of the form and function the same.

We can keep playing 29 questions, which a picture would help.........

Are the entry wires/solder balls exposed inside of the device? How much room is inside?
28 questions left... ;) http://www.thegsresources.com/_forum/showpost.php?p=1910265&postcount=1

The ends opposite the hard shells are potted along with the rest of the electrical components. The undersides of the two relays (PCB side) are partially obscured making it difficult to replace or unsolder them.
 
28 questions left... ;) http://www.thegsresources.com/_forum/showpost.php?p=1910265&postcount=1

The ends opposite the hard shells are potted along with the rest of the electrical components. The undersides of the two relays (PCB side) are partially obscured making it difficult to replace or un solder them.

Well the only obvious solution to that is to make a small universal board, cut the wires from the TSCU, solder them to the new board and stuff the whole thing into the original enclosure (or NOT). Then you have the same harness end connections.

You could repot the thing even with what ever space you can hog out of what is there.
 
Well the only obvious solution to that is to make a small universal board, cut the wires from the TSCU, solder them to the new board and stuff the whole thing into the original enclosure (or NOT). Then you have the same harness end connections.

You could repot the thing even with what ever space you can hog out of what is there.
Yep, hog it insides out of the old unit to fit a replacement board or mold a new housing. Or, if the replacement unit is small enough, hog out a little of the real estate and fit the replacement under the metal cover. ;)

In days past, had given thought to making a mold and casting a dozen or so. We'll see what the future holds for me. I might revisit it some day. Need to concentrate on getting the Skunk finished and rebuilding the lean-to attached on the back of my garage this year; plus the house needs to be repainted as well.
 
Yep, hog it insides out of the old unit to fit a replacement board or mold a new housing. Or, if the replacement unit is small enough, hog out a little of the real estate and fit the replacement under the metal cover. ;)

In days past, had given thought to making a mold and casting a dozen or so. We'll see what the future holds for me. I might revisit it some day. Need to concentrate on getting the Skunk finished and rebuilding the lean-to attached on the back of my garage this year; plus the house needs to be repainted as well.

I don't see any need to create a mold when the only point of the enclosure is to look like the original and the original is what you already have.

I'll see if it fits into my schedule.
 
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