[Techtoolslist] ADDR ERROR @ XXXXh - LOOP? = Address line issue

[John Robertson]

On 2019/01/11 5:25 p.m., John Robertson wrote:
> And here is a new one for me, don't recall seeing that error message 
> before, nor can I find reference to it in the 9010A Operator Manual.
>
> Pressing the MORE key gives me "ADDR BITS 0100 - LOOP?" so I assumed 
> this was some sort of a decode issue and will proceed accordingly. 
> Just thought I would post it here in case anyone else runs across this 
> rare error message which I assume was added to the 3A ROMs in the 
> 9010, but not to the manual - at least the copy I have...
>
> (later) It was indeed a problem with some address lines. For only A7 
> and A8 when loop reading @ 0000 (easiest - all should be Low) with the 
> 9010 probe (set to Address) the Low light was flickering, not steady 
> Low. Turned out to be a 74LS367 that had two inputs that were somehow 
> pulling the lines slightly high. This did not show up when doing a ROM 
> or BUSS test - only in either of the RAM tests.
>
> FYI
>
> John :-#)#
>
Still later.

Ran into this "ADDR ERROR @ 0000-LOOP? again, this time it was an 
Address line (A5) shorted to a Data line (D7). It doesn't matter which 
Data line the address line is shorted to, it gives the same message:

Any Data line shorted to A0 gives/More ADDR BTS 0001-LOOP?
Any Data line shorted to A1 gives/More ADDR BTS 0002-LOOP?
Any Data line shorted to A2 gives/More ADDR BTS 0004-LOOP?
Any Data line shorted to A3 gives/More ADDR BTS 0008-LOOP?
Any Data line shorted to A4 gives/More ADDR BTS 0010-LOOP?
...
Any Data line shorted to A15 gives/More ADDR BTS 8000-LOOP?

FYI.

John :-#)#

-- 
                  John's Jukes Ltd.
7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
Call (604)872-5757 (Pinballs, Jukes, Video Games)
                  flippers.com
  "Old pinballers never die, they just flip out"