PDP8/e programmers consoles

[allison]

On 03/16/2018 10:31 PM, Kyle Owen via cctalk wrote:
> On Fri, Mar 16, 2018, 20:58 allison via cctalk <cctalk at classiccmp.org>
> wrote:
>
>> On 03/16/2018 08:28 PM, Charles Dickman via cctalk wrote:
>>> So the PDP8/e used the KC8-EA programmers console which has
>>> incandescent indicator lamps and the PDP8/f used the KC8-FL
>>> programmers console which has LED indicator lamps.
>> Wrong.  The 8f uses the same as the 8e.  It was the 8m that had the
>> LED console.  If memory serves it was date of design that influenced it.
>>
> I have seen several 8/f systems that have LEDs, for what it's worth. I can
> only imagine DEC was transitioning the 8/m and 8/f to take LEDs instead of
> incandescents.
Work for DEC, 10 years from 1983 and very rarely saw them and those in the
region (the greater Maynard area) around DEC never seem to have LEDs
unless added later.   There was a third part bulb replacement.  They were
dim then as well and not popular.  I got lucky and found one but, dim red
LEDs are unappealing so its put aside as a spare or maybe to build up
another machine.

>> I can be certain as I have an 8f built in 1973.  I've since moded it to
>> take bright yellow LEDs as lamps are not easy to find and annoying
>> to replace.  If I care to I can put the lamps back.  Since I put
>> operational
>> over absolute faithful its better as is, less digging in the box.
>>
> The bulbs are still available on Mouser. I've ordered a bunch for my 8/e
> and have been very happy with them.
>
> http://so-much-stuff.com/pdp8/repair/bulbs.php
I know, I have a stock, but you have to pull the panel apart to replace
them,
gets tiring.  Modern yellow LEDs are nice and bright, and don't burn out.

Less digging in the box is a good thing as over time fumble errors can
hurt it.
One _*oops*_ during assembly could be painful.

>> However its possible to swap the panels, I tried it once and it pass diags
>> and worked fine.  Didn't like the red.
>>
> I've found that my LED 8/m is very hard to read, as the LEDs are very dim.
Back then they were terrible.  I have a supply of old ones and at 9mA they
were dim and at 11mA the died!  Modern red leds at 8mA are very much
brighter.
However the yellow look more like lamps.

Every so often I look at is and wonder if a mix of yellow and white
in groups of three might be cool looking. but then I have to take it apart
when not broken, the thing I am trying to avoid.  ;)
>>> Another console question...
>>>
>>> Has anyone ever seen a PDP8/i style console for the PDP8/e? Looking at
>>> the way the PDP8/e console functions, it should be possible to time
>>> multiplex all the register to the data bus so they are all visible at
>>> once when the machine is halted.
>> No and can't!   The 8i (nor the 8L) was not omnibus.
>>
> I think he's aware (hence "style").
I've seen a one off 6100 (CMOS 8) with a 8i like front panel. it was
made rather poorly
and not structurally strong so who knows if it exists still.  The basic
idea is easy
to do on any 8.  But nearly 60 lamps/LEDs later and all the switches its
going
to take time to build.   It would be terrible if someone were to junk an
8I or L
just for the panel.

The front panel also is part of the 8 evolution to a more desirable
turnkey machine
which is what the users wanted.  One described it as "I want to use it
not sit there
and flip switches all day".   Oddly it was Field service that wanted it
the panel as
it was a good debug tool and retained.    Systems with mass storage as a
nominal
thing helped to kill the front panel.


Allison
> Kyle
>