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TomWhitwell / Turing-Pulse-Expander

Rev 2 Turing Pulse Expander
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Mk2 - Led 7 always on #3

Closed Madsiboy1995 closed 3 years ago

Madsiboy1995 commented 3 years ago

Hey Tom Thanks for some great modules. Just finished building Turing Machine + Pulses MK2. Unfortunately LED #7 is continuous and not pulsing like the rest.

Is there an explanation for this?

Best regards

TomWhitwell commented 3 years ago

Hi, that must be annoying. This isn’t a problem I’ve heard of before.

A few ideas about how to approach it.

As an experiment, try temporarily connecting the pulses to the other (gate) output on the back of the Turing. You’ll see the lights stay on for the whole step length (rather than blinking with the clock).

If LED 7 is flashing on and off with the others, the problem is in the Turing module. If it is permanently on, the problem is probably in the expander.

If the problem is in the expander - that’s good, because it’s a very simple module.

Are the LEDs on the right working as you’d expect? Does step 7 output a changing pulse, or is if always on?

Madsiboy1995 commented 3 years ago

Wow Tom! So fast response.

I've tried changing out the resistors, but in the end it turned out it was a small shortage at the chip. Eveything is working now!