DEC Pro 350/380 Memory Cards - Interchangeability?

[Rob Jarratt]

> -----Original Message-----
> From: Paul Koning [mailto:paulkoning at comcast.net]
> Sent: 29 August 2016 18:10
> To: rob at jarratt.me.uk
> Cc: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at classiccmp.org>
> Subject: Re: DEC Pro 350/380 Memory Cards - Interchangeability?
> 
> 
> > On Aug 29, 2016, at 12:33 PM, Rob Jarratt <robert.jarratt at ntlworld.com>
> wrote:
> >
> >
> >
> >> -----Original Message-----
> >> From: Paul Koning [mailto:paulkoning at comcast.net]
> >> Sent: 29 August 2016 15:08
> >> To: rob at jarratt.me.uk; General Discussion: On-Topic and Off-Topic
> >> Posts <cctalk at classiccmp.org>
> >> Subject: Re: DEC Pro 350/380 Memory Cards - Interchangeability?
> >>
> >>
> >>> On Aug 28, 2016, at 5:11 PM, Rob Jarratt
> >>> <robert.jarratt at ntlworld.com>
> >> wrote:
> >>>
> >>> I have a 350 and 380. Neither work. The 380 is reporting a possible
> >>> memory error on the LEDs. Will the 350's memory work in a 380 (or
> >>> vice
> >> versa)?
> >>
> >> The 380 has memory on the motherboard, and a model-specific
> >> daughtercard for expansion memory.
> >>
> >> It seems reasonable that the Pro bus (I/O card) expansion memory
> >> should work in both models, but I don't have any to try that.
> >>
> >> If you have a 380 complaining about memory and it has a Pro bus
> >> memory card installed, I'd suggest removing that card to see if it's
> >> happy with
> > just the
> >> stock motherboard memory.
> >>
> >> 	paul
> >
> > Just reading your reply again. Are you saying it has enough memory on
> > the board, without using a daughter board? I did see lots of memory on
> > the main board, but assumed it was video memory. I did try removing
> > the daughter board altogether at one point, but it still didn't work.
> > :-(
> >
> > I wish I had a logic analyser.
> 
> You should get the Pro 300 technical manual (two volumes) from Bitsavers.
It
> contains a great deal of relevant detail.
> 
> From Volume 1, page 4-4 summarizes the system memory for both models.
> Page 5-129 describes the memory daughter cards of the Pro-350.  Page 6-125
> describes the memory daughter cards for the Pro-380.
> 
> I misremembered the 350 (I don't have one): it can have memory in the I/O
> card cage, but it also has memory daughter cards, two of them, with 40 pin
> connectors.
> 
> The Pro-380 has main memory on the motherboard.  It also supports an
> optional expansion card, just one, with a 48 pin connector.  The pinouts
> shown for the two types of daughtercards make it very clear that they are
> entirely incompatible.
> 
> The Pro-380 also has graphics on the motherboard (though EBO is an option,
> via a daughtercard).  So a Pro-380 with nothing in the I/O card cage
should
> power up and give you a display on the screen (presumably one complaining
> about not having a bootable device controller...).
> 
> On the other hand, the Pro 350 uses a graphics card in the I/O cage, and
EBO
> is a second I/O card connected to the main one via a jumper cable.
Neither
> of these is compatible with the Pro-380.
> 


Thanks, I see that now. Definitely no compatibility :-(. Just need that
logic analyser really to work out what is the matter with them both. When
the 380 doesn't have the daughter board installed it leaves all the LEDs on
to indicate a system board error. The 350 has the same symptoms with or
without the memory boards. Strange though that the manual mentions a
standard option with memory on the backplane, I don't think my 350 had that
installed. I also notice that the printer port can give access to ODT, I
will see if I can get anything out of that later.


> I have somewhere a printout (on 11x17 size paper, roughly A3) of the Pro
380
> motherboard schematics.  I haven't seen those elsewhere.  I haven't tried
to
> scan them but try if there's interest.
> 
> 	paul