Options for resurrecting VAX 4000/400 and Vaxstation 3200

[Dr. Roland Schregle]

On Thu, 10 Mar 2016 14:23:34 +0100, Peter Coghlan  
<cctalk at beyondthepale.ie> wrote:

>>
>> FWIW, here's a thermography (hope the link works) of the B-cache  
>> section of the KA-675 after being powered up for ca. 30 mins:  
>> https://www.dropbox.com/s/2nsx1dfngp1jfq5/TH710065.BMP?dl=0
>>
>> Note that the rightmost chip just below the CPU heatsink has a pin  
>> that's ca. 2 degrees warmer than the others. I don't know if that says  
>> anything, but it *is* reproducible. Maybe I should start with that one.
>>
>
> I can't really make it out on the image but if it is just one pin that is
> hot, maybe there is nothing more complicated wrong than a bad solder  
> joint
> at that pin, particularly if it is a power or ground pin.

Hi Peter,

I've already reworked that pin, but to no avail. :^(

I've converted the pic to grayscale for better contrast and highlighted  
the pin in red:
https://www.dropbox.com/s/ss76hldqxziazyc/ka-675-1.png?dl=0

For comparison, here's a thermograph of the 2nd KA-675 with the dead DSSI  
controller:
https://www.dropbox.com/s/8twvrytrr60mrb9/ka-675-2.jpg?dl=0

The artefact doesn't show up on the 2nd board.  Might be a long shot tho.  
I'm not sure a chip failure would even show here. This was more of a lame  
experiment, since we have the thermal tracer in the lab anyway (and the  
pix look cool).

--GT


-- 
"END OF LINE" [MCP, 1982]
"... nowhere in the standards is it specified that 'programs that use a  
lot of memory may randomly crash at any time for no apparent reason'"  
[Stackoverflow forum, 2012]