Separate Brake Light From Turn Signal

[ThomsCircuit]

Does your truck's flasher lights look to flash equal time on/off?

Yes. Thank you. I will modify my circuit and replace the pot with a 100k resistor.

 

[eTech]

I adjust the pot to match my trucks turn signal rate of 85 cycles per minuteView attachment 147361

You might try this 555 circuit configuration. It will maintain 50% duty cycle regardless of frequency.
You can use the same LED configuration in this circuit, I just didn't show it.

 

[ThomsCircuit]

Does your truck's flasher lights look to flash equal time on/off?

I made the change, setting the pot to 100k and the circuit has improved.
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with both inputs flashing the output flashes.
with RTB flashing and LTB solid there is no output
with LTB flashing and RTB solid the output flashes
with both inputs solid there is no output.
EDIT
with RTB flashing and LTB out there is no output
with LTB flashing and RTB out there is no output
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I will continue to check and compare my breadboard to yours and the schematic.

Thank you for the improved 555 circuit.

 

[eTech]

Here is a table that lists the input and required outputs.
It is based on a vehicle approaching an intersection.
"RT APPR", as an example, means "approaching an intersection with intent to make a right turn".
"RT WAIT" means "at intersection with intent to make a right turn, brake applied".
etc..

Please review and comment.

 

[ThomsCircuit]

Please review and comment.

This is exactly how it should function.
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Cleaning up after the storm. Trees down, neighbors need feeding as I seem to be the only one with power.

 

[ThomsCircuit]

Once I realized that the diodes and capacitor could be connected to the BB like this it made connecting everything else a bit easier.
I have not powered this up yet as some neighbors still have no power so I'm cooking for the older folks. I did this last night and it did not take too long. I have realized and learned a great deal. I still plan on testing all pins and junctions as you have laid out in post #152

 

[ThomsCircuit]

2C. When +12V volts is applied to both U1-14 AND U1-6, the voltage at U2-1 should be +12V.

While I was performing these tests I ran into a short in U1 and the IC smoked at pin 4.

I got this far
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To test this function, remove the connections to pins U1-5,6,13,14,
then temporarily connect these pins to 0V (ground). Pins U1-5,6,13,14
will be called the "input pins" from here on for testing purposes.
1. Apply power to circuit.
1A. Check the voltages at pins U2-3,4,8,9,10,11,12,15. Each pin voltage should be ~0V (ground)
1B. Check the voltages at pins U2-2,7,16. Each pin voltage should be +12V.
1C. These voltage measurements should remain constant throughout this test.
2. Check the voltage at U2-1.
2A. With 0V volts at ALL input pins, the voltage at U2-1 should be 0V.
2B. When +12V volts is applied to U1-14, the voltage at U2-1 should be 0V.
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all was well but when I moved pin U1-6 from ground to power the chip smoked.
2C. When +12V volts is applied to both U1-14 AND U1-6, the voltage at U2-1 should be +12V.

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Before I began these tests this was the state of the circuit

Output for each
1 L
2 L
3 L
4 L
5 L
6 F
7 L
8 L
9 F
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I will post some breadboard photos. After making this 4 times and comparing mine with yours I could find no differences except for the 3 diodes at the circuits input that were not in yours. I will post a few BB photos.

Thank you for your assistance.

 

[ThomsCircuit]

BB of circuit.
I apologize for so many photos but I think at this point finding mistakes in my BB might be helpful.

Memo: The last few folks in my neighborhood had their power restored yesterday after being knocked out by H-Milton Last Wednesday night.
This wide shot may be the most useful

 

[ThomsCircuit]

"To test this function, remove the connections to pins U1-5,6,13,14,
then temporarily connect these pins to 0V (ground). Pins U1-5,6,13,14"


In order to do the above it was easy enough to set 5& 6 to ground but for 13 &14 I removed Rx2 & D2 but I left the cap C2 connected to pins 14&15.
I want you to know I have no intention of giving up on getting this right. I do want to perform the tests that you took the time to document. I have 18 more 14538's I am just a bit stuck and need advice on how to avoid blowing another chip before I repeat the tests
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I also (before the smoke signals) re-did the test you outlined in post #142. I may have mis-understood just how much of the tests to perform but I did each junction block repeating 2A-2B. The results were

#142
1. Disconnect LTR wire from Q3-collector while leaving R12 connected to Q3-C.
Then apply 12v supply power to the circuit.
2. Check the voltage at Q3-Collector.
2A. With ~0V volts at "LTB" input, the voltage at Q3-C should be ~ +12V.
2B. With ~+12V volts at "LTB" input, the voltage at Q3-C should be ~ 0V.
If "Left Blink Input" block passes these tests, it works, then move to the next block.
----------------------------------------------
LTB
J1 WORKS
J3 WORKS
J5 STAYS HIGH

RTB
J2 WORKS
J4 STAYS HIGH
J6 WORKS

NOTE:
I did use the new 555 circuit you posted for the tests