Service manual

If self-test passes, the large yellow LED at the top of the LEDs is ON. (Here
self-test means both the on-board power-up tests, RBD 0, and the CPU/
memory interaction tests, RBD 1.) The top red LED (next to the yellow
one) is also ON, and the next five red LEDs are OFF. The bottom LED
is OFF if the processor is the boot processor, and ON if it is a secondary
processor.
If self-test fails, the yellow LED is OFF, and the red LEDs contain an error
code that corresponds to the number of the failing test. The test number is
represented in binary-coded decimal. In the seven red error LEDs, the most
significant bit is at the top, but the lights have a reverse interpretation —
a bit is ONE if the light is OFF.
For example, assume a processor fails self-test (yellow LED is OFF) and
shows the following pattern in its seven red LEDs:
TOP
(MSB) on 0
off 1 = 3
off 1
on 0
on 0 = 2
off 1
on 0
BOTTOM
The failing test number decodes to 011 0010 (binary-coded decimal 32). If
you then ran RBD 0 with the /TR and /HE qualifiers, the last test number
you would see displayed is T0032.
When any of the red error LEDs is lit, a failure has occurred during the
self-test sequence. But system power-up self-test actually comprises three
sets of tests: <REFERENCE>(XRP) power-up tests (RBD 0), CPU/memory
interaction tests (RBD 1), and VAXBI adapter (DWMBB) tests (RBD 2).
Interpretation of the processor board error lights depends on which set of
tests was running, as explained below and in Table 4–2.
<REFERENCE>(XRP) Scalar Processor 4–21