DEC 3000 (alpha) faultfinding

[Maciej W. Rozycki]

Hi Peter,

> However, they do not provide the SROM> prompt or accept mini console commands
> unless a I engineer another fault condition such as by pulling out one of the
> memory risers.  I wonder if there is a jumper to enable mini console commands
> to be accepted without doing this? Looking around the system board, I see a
> pair of jumper pins labelled J9 hidden under the I/O board which looks like it
> could do this.  Unfortunately, while there is legend on the PCB indicating the
> function of all other jumpers, there is none for J9 and it is not mentioned in
> the manual either.

 "DEC 3000 Models 600/600S AXP and 800/800S AXP Service Information", 
Order Number: EK-FLSPC-SV. A01 (flspcsva.pdf) seems to indicate on page 
2-2 that the SROM console jumper is one in position 0 among the SROM 
jumpers whose location is shown in the figure on that page.  I have 
checked my /700 (which is the same as the /600 except for a faster CPU) 
and this is also marked J8 on the PCB.

> The 600 machines have a socketed 27C512 EPROM.  I assume this must be the SROM
> (although I can't see what is serial about it) as the machines fail to update
> the diagnostic LEDs or write to the mini console if it is removed.  I dumped
> the two EPROMs and compared them and they are identical.  However, I can't see
> any ASCII strings in them.  Perhaps the bits are not used in the standard
> order?  The manual suggests that there are 8 different 8KB SROM images present
> and those other than the "standard" one may be used for testing and diagnostics
> by setting jumpers. Unfortunatly, there is no further information about these
> images.

 The location of the SROM chip is also shown in the figure on page 2-2.

> The format of the headers in the SYSROM and IOROM do not exactly match the
> format given in the manual but they are "close".  I wonder if this might
> be my problem or if the manual is incorrect.  If anyone else has a 3000 600,
> could they take a peek at their SYSROM and maybe we could compare notes?

 I could check my /700 with SRM.  What would you like me to look at?

 Hope this helps.  Good luck with your fault debugging.

  Maciej