4 May
2012
4 May
'12
12:06 p.m.
The DEC Pro 350 I got came without a monitor, cable or keyboard. When I
power it up the diagnostic LEDs on the back all come on. The docs I have
suggest this means a system board error. However, I am not sure if this is
because there is no monitor or keyboard attached. Might this behaviour be
expected if I don't have anything connected to the video connector? I tried
It won't mind that there;s no monitor, it will give an error if it can't
find the keybaord, but it'll get a lot further than 'all lights on'. In
fact I am not even sure that a keyboard error does show up on the
diagnostic lights.
The power-on reset signal turns all the lights on. One of the first
things the CPU does is to turn at least one of htem off. So if they're
all on then most likely rither the CPU isn't running at all (or at least
isn't runnign the bootstrap at all), or the thing is being held in the
reset state.
I suspect that the reset signal is generateed from some kind of power-OK
signal so that if there's a power rail out-of-spec it'll stick in the
reset state. What I can't rememebr if is fhtat signal originates in the
PSU or not.
There is a Technical manual for either the Pro350 or 380 on Bitsavers and
a printset for the other one. The 2 machines are quite different but I
think the PSU connector is the same, so you can start there....
connecting a terminal to the serial port just in case
something happened
there, but I don't see anything. Does the Pro 350 use the serial port as any
kind of console port by any chance? I suspect not.
I am trying to identify what cable I need. I think it is a BCC02, but if it
is a colour machine it would be a BCC17, but I don't know how to tell if
this is a colour machine or not. There also seems to be a BCC03 cable used
on Rainbows, anyone know if that would work?
A colour 350 has 2 boards for video in the cardcage with a little ribbon
cable linking them across the top. If you have such a cable, thrn the
colour board is fitted.
I am not sure the exact details of all the cables, but the Pro and
Rainbow video conenctors do haev diffenreces in terms of which signal is
used. The conenctor is a DA15, there are 4 pins fot hte keyboard, a 12V
power lien for the mono monitor and 4 video signals, R,G,B and mono. I
would look at both mono and green to see if there's anythign resembling a
video signal on either. Or just try a composite (RS170 rate) monitor on
mono and green in turn. You won't damage anything.
Do you have my notes on the universal video cable for the DEC desktops?
-tony