Microvax II 'primer'?

Jon Elson elson at pico-systems.com
Sun Jan 21 14:02:09 CST 2018

On 01/21/2018 01:25 PM, Jules Richardson via cctalk wrote:
> So, I picked up (and I did just carry it into the house, 
> and now I hurt) a Microvax II from another list member 
> yesterday. Cosmetically it's a disaster (BA123 has a 
> cracked top panel, broken wheels, missing front door, 
> missing right-rear panel) but internally it appears to be 
> complete; board wise we have:
>   M7606 - CPU
>   M7608 - 4MB ram
>   M9047 - grant continuity
>   M7504 - DEQNA ethernet
>   M3104 - DHV11 8-port serial
>   M7555 - RQDX3 disk controller
>   M7546 - TX50 controller
> ... it's got a TK50 and hard drive (no idea of capacity).
> Operational status is a complete unknown, and I have 
> absolutely zero knowledge about these systems - so my 
> question at this stage is what background reading I need 
> to be doing in terms of pre-powerup* checks, actually 
> hooking a console, if there's a suggested minimal config I 
> can use to diag the CPU, and then (assuming it gets to 
> that point) how to actually use the thing (I'm assuming it 
> was running VMS rather than Ultrix, but I don't know for 
> sure). I'm wondering there aren't any handy tutorials out 
> there, alongside whatever DEC docs are recommended.
> * e.g. for most machines I'd be thinking in terms of 
> pulling all boards/drives, hooking up a dummy load to 
> whatever PSU rails required it, and then at least running 
> the PSU up in isolation first, but I don't know to what 
> extent this machine requires some logic in place for the 
> PSU to even run.
Well, you need to hook up a serial terminal, set the baud 
rate, and see if it gives the power-on self diagnostic sequence.
The TK50 is likely not going to work due to deteriorated 
rubber rollers and such.  Does it have a disk drive?
If not, it won't do much.  If it does, it is a bit iffy if 
the drive will spin up and unlock heads.  I have a similar 
setup here, but my SCSI disk drive died.  The CPU still 
fires up just fine - amazing for a machine I ran for 21 years.


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