PDP-8 CPU question

[vrs]

>    Anyway I've been reading the PDP-8a User's Manual and trying to figure
> out what all I have here and I have a question about the PDP-8 CPUs. DEC
> offered two different CPUs for the PDP-8, one is the KK8-A which is a
> single M8315 card. The other is the KK8-E which consist of an M8300 and
> M8310 cards which are the CPU and an M8320 Bus Loads card and a M8330
> Timing Generator card. Can someone explain the differences between the two
> and why DEC offered two very different CPUs for the 8?  Can I replace
> simply the M8300/8310/8320/8330 cards with the M8315?

The M8300/10/20/30 cardset is quad-height, and will fit in (was originally
designed for) an 8/e/f/m backplane.  The M8315 is hex-height, and will only
fit in an 8/a backplane.  The nice thing about it is that it has more
features and less slots.  (I think you'll still need the bus terminator
card, though.)

>   I also have a question about the diagnostic paper tapes. Does anyone
have
> a ROM emulator or other way to load the diagnostics without using a PT
> reader? Yes, I know there are some SIMPLE diagnostics that can be loaded
> from the Programmer's Panal but I concerned about the more extensive
> diagnostics. In fact, I'm wondering if anyone has tried burning the
> diagnostics into PROMs and installing them in place of the Boot Roms on
the
> M8317 card.

I'd configure the ROM to boot to RIM (or is it BIN?) loader, and use the
console interface to talk to a PC and download the binary images.  Anyone
done this?

If you have a programmer's panel, you can just enter the RIM loader by hand,
and go from there.

>   Can anyone explain the purpose of the small card that plugs into the
back
> of the chassis near the power regulators? It's not mentioned in the User's
> Manual and I don't even know it's name. Thom says that it controls the
> power and the machine will be completely dead if it fails but that's all
> that I know about it.

Does it have a part number on it?  (I haven't looked too hard at the power
supply side of mine yet.)

    Vince