[Techtoolslist] Fluke 9010 bus test address tied message confusion

[David Shoemaker]

Working on a space invaders board.  

8080 pod, passes self-test.

 

Put it onto UUT and hit auto.  Getting an error that does make sense.

 

ADDR bits 13 tied-Loop?

 

Thought at first that was bits 1 & 3 tied.  But probing around didn't find
anything.  So I tried tying them together myself to see what happens.

 

ADDR Bits 1 and 3 tied - loop?

 

Uh, ok so they are explicit on the two bits tied.  That's good to know.  But
why is it only telling me one bit?

 

So I pulled out the manual and from the bus test error messages table there
should never be a "bits" message without two bits.  But I am only getting
one (and no MORE led, and more button does nothing).

 

The only single bit error should be if bit tied low or high. But that is not
the message (and it says "bit" not "bits").

 

 

I tried exercising bit 13, did a write @ 2000 = 0, probe set on address and
can see the line being driven high.  And no other bits are being driven when
I check.

 

 

Thoughts?

 

Thanks,

David