OK Thanks again John.
Im just doing the Trackwork now. :-)
Ive ordered the chips and transistors, they should be here in a day or two.

Regards
Wombat.

"John Fields" wrote in message
...
On Thu, 16 Nov 2006 10:21:40 -0500, "Wombat-Pipex-News"
wrote:

-----------
Press 3 and C lights, AB off, don't you mean?
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Yaa. :-)

I presume on the diagram that the chips are already supplied by +5V to
both
pin14s and GND on Pins 7.

---
Yes.
---
Also on the second 74HC02 does the UC2 UCD pins 10 13 need grounding via a
resistor?

---
No.
---

As the outputs would be High until the button was pressed.

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The outputs of U2C and U2D will _always_ be high, regardless of
whether S3 is made or not, since their inputs are wired to ground.

Notice that R5 is used to pull U2-5 down to 0V when S3 is open.
---

Or can I just leave them unconnected.?

---
Yes. They're outputs, so there's nothing critical about them.


--
JF