Disk drive parts

Tony Duell ard at p850ug1.demon.co.uk
Thu Aug 4 18:27:17 CDT 2005

>  The RK05 uses a DEC backplane
> >block internally, with genuine Unibus cables (RK11D) or a DEC-style
> >paddle connector and 40-pin ribbon cables (RKV11D, RK8E). 
> >_Electrically_ the Diablo 30 should be the same as a real RK05, but
> >mechanically, the cables are entirely different.
>    Yeah that was an unplesant surprise!   

Althoguh if you get a real Diablo cable, it has the connector mounted on 
a little PCB, with a trasnistion connector and then a length of ribbon 
cable on that. If you take off one end, the wires are in almost the right 
ordser to solder to a DEC 'unibus' cable board to link to the RK11-C or 
whatever. I wonder why :-)

>    BTW I found out that the d30 uses an external power supply. Does anyone
> have the specs or pinout for it or even an extra PSU?

I thought the manuals were on bitsavers. The PSU pinout should be in 
there. There were 2 PSUs from Diablo, one using a transsitorised 
regulator, the other using a ferroresonant trasnformer. DEC also made 
their own PSU (H734 or something) for these drives.

>    Joe
> >
> >The drive chain also needs to be terminated.  In the case of an RK05,
> >it's an M930 Unibus terminator in the last drive.  Not sure about a
> >Diablo 30, unless you hang a real M930 off of one of those cable

The Diablo terminator is a PCB stuffed with resistors soldered to the 
connector. There's a +5V pin on the connector to power the terminator, of 
course. I have _one_ of them, I also have 2 drives and the 
interconnecting cables, so it's not up for grabs.


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