Help w/DEC H742 +15V...

Josh Dersch derschjo at mail.msu.edu
Mon Apr 13 14:26:10 CDT 2009



Tony Duell wrote:
>
>> ACLO & DCLO are active-low signals at the time when I was testing out 
>> the supply...)  Guess I get to pull the supply again and do some more 
>> debugging :).  Is there a quick 'n dirty way to fake out/bypass these 
>> signals so I can at least see if the CPU runs at all?
>>     
>
> If you disconnect the wries between the PSU and the backplane (just 
> remove the pins from one of the mate-n-lock connectors, but rememerb 
> where they go!), the signals will be pulled high by the Unibus 
> terminator. I don't know if everything will initialise properly in that 
> case (I think it should do), but at least the CPU will do soemthing.
>   
Thanks -- just tried this, and I still get the same behavior from the 
CPU.  ACLO and DCLO are now pulled high.  Well, this is going to be a 
fun project :).  Guess I need to start debugging the CPU, any 
suggestions on where to start?  (Anyone have a Unibus extender card?)
> -tony
>
>
>   



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