Fixing board, Easy question HEX SCHMITT

[doeby]

I have a little board for ivan stewarts off road racing. it controls the steering wheel. the chip in it is a sn74ls14n
I think this is the problem, saw a post with same problem, and that was his fix.
Which is a HEX SCHMITT-TRIGGER INVERTER.
The chip has 6 input/output "channels" what happens is the input comes in on pin 1 and is output on pin 2. The board then has a trace that
connected pin 2 to pin 3. So then signal goes to input 3(pin 3) and then outputs to pin 4. That is then output to main PCB board. So input signal is going threw 2 of the input/outputs gates.
My questions.
Does it change anything going threw 2 of the gates?
Is it inverting it twice...and changing the signal, or just cleaning up the signal twice.
How can i test the chip, to see if that is the problem?
What are the odds that some of the gates are not working, but the ones not used would still work?
SO i could put a jumper wire from input to not used gate 5/6 . and output 6 to main PCB.
Could i also just get a replacement chip, and set if on top of old chip, and solder to those legs. The board is really old, and i think i would
ruin traces, if i tried to de-solder, and put a new one in.(i know, not the correct way to fix it)

 

[Galgso]

Does it change anything going threw 2 of the gates?
Is it inverting it twice...and changing the signal, or just cleaning up the signal twice.

The circuit probably needs an output signal that is in phase with the input. If it went through one gate only it would invert the signal (180° phase shift).

What are the odds that some of the gates are not working, but the ones not used would still work?

Highly unlikely. ICs generally do not fail partially. They either fail fail completely or are fully functional.

Could i also just get a replacement chip, and set if on top of old chip, and solder to those legs.

No. If the old chip is dysfunctional, it would interfere with the new chip unless you remove it. You can cut the pins off so you can remove the body of the IC and then desolder the pins from the board individually which would be easier than trying to take out the whole chip at once.

Also try to make sure that the chip is actually faulty or at least rule out other common failures (broken traces, leaky capacitors, etc.) before attempting to replace it.

 

[ZipZapOuch]

I don't agree that all channels in a 6-channel inverter fail at once. But, I think you should look at loose/broken/cracked solder joints near the chip if (what I assume to be) a pinball machine or video game shakes or vibrates.

Try reflowing the solder on each pin of the chip. Just a quick touch with some fresh solder added. You might want to polish the tips of each pin on the back side of the board before reflowing the solder - uses a soft pink eraser to polish.

Also, check the whole board for corrosion or cracks.

 

[doeby]

thank you for the answers, i did check to make sure all the pins of the chip are connected at the other end of the traces. it is an arcade game, and the symptoms are identical to someone who said it was the chip on there's.
Only difference on this one, is it will work for like 2-5 minutes then fail. So i assume the chip is getting hot, and then failing. Only other thing it really has is an optical sensor, Not sure how to test that. I would think that an optical sensor wouldn't get hot and stop working, a chip would. I feel like i could do the Pins on top of the board like you suggested, That is a great idea.

 

[Nigel Goodwin]

Get a can of Freezer spray, and give the chip a squirt, see if it starts working again. But to be honest, I wouldn't expect a simple hex inverter to be running hot anyway?.

 

[crutschow]

I wouldn't expect a simple hex inverter to be running hot anyway?.

It could if one of the inputs is floating.
All all the gates being used?