DEC 3000 (alpha) faultfinding

[Peter Coghlan]

>
> > J8 (position 0) is where the jumper already is on both my 3000 600 machines.
> > It is possible that this is where it normally is, however, it is also possible
> > that I moved it there some time ago in an attempt to diagnose the problem and
> > I have since forgotten.  Which position is the jumper at in your system?
>
> It's in at position 0 (J8), as per documentation.
>

It looks like position 0 (J8) is the normal operating position for the jumper
then and I did not move mine previously.  With the jumper in this position,
I get some mini console output on power up but I do not get an SROM> prompt
and I cannot enter mini console commands unless a machine check happens or I
force an error by removing a memory riser or doing something else to cause
an error.

If I put the jumper in position 3 (J6), I get this:

DEC 3000 - M600 SROM 6.1
Mini-Console
ff.fd.fb.fa.f9.f8.f7.f6.f5.f4.f3.f2.f1.f0.
sysROM  00000033.000006f1
ioROM   00000033.00000162
MCRstat 11111111.808011c0
bnkSize 00000300.00000c01
memSize 000000c0.000000c0


SROM>

which seems on first glance like what I am looking for.  However, commands are
not accepted or echoed which is strange!

Even more strange, if I put the jumper in position 2 (J7), I get exactly the
same output and the same lack of response to commands but at 19200 bps while
pretty much every other setting talks at 9600 bps (except for position 7 (J1)
which doesn't seem to do anything).

The remaining settings perform some cache tests and produce lots of failures.
It looks I can only enter mini console commands with the jumper in position 0
(J8) after some error has happened.

(I do not get anything on the MMJ console port under any cirumstances.)
           
>
>  These must be the alternative diagnostic routines mentioned the system 
> programmer's manual:
>
> "A DECchip 21064-AA CPU, including on-chip 8-KB instruction and 8-KB data 
> caches, and a 64-KB serial boot ROM.  A 64-KB stream holds the primitive 
> boot code for booting the operating system.  Jumpers provide for the 
> selection of up to seven other streams for diagnostic and other purposes. 
> (The entire UVPROM is 64 K x 8.)"
>

Yes.  I didn't bother trying these jumpers earlier as not having description
of the the diagnostics, I thought their operation might be rather obscure.
Happily some of them at least are pretty simple and obvious.

>
> I take it F0 is the last output from SROM before handing control over to 
> SRM.  Now that you've got a way to see SROM diagnostic output directly I 
> would expect these codes not to matter as much anymore.
>

It appears I was confused.  In chapter 14 of flspcsva, table 14-1 "Power-Up
Test Serial ROM Codes" seemingly applies to the DEC 3000 800 only, despite
being in the part III "Common System Information" section of the manual.

Regards,
Peter Coghlan.

>
> Maciej
>