Switch orientation

[Christian Kuhtz]

Hi there,

I, too, built the PiDP-11 from the most recent batch and the a PiDP-8 shortly thereafter.  As I was doing some research on the PDP-11 as I was trying to learn it, I found a couple of references to the start switch being a momentary up (as the only one) rather than momentary down like all others. While I worked on a PDP-11 on a terminal, I never got to mess with the face of one myself.

Does anyone have any comments on this? Is momentary up the right way for the original? Flipping it around would mean cutting traces and running a wire, I think.  

Just wondering what the original actually is.

Thanks,

Christian

[Digby R.S. Tarvin]

I have an original PDP11/70 front panel - and can confirm that there is one momentary UP switch. However it is not START, it is DEP. (Makes sense when you think about it - what you least want to do by accident when fiddling on the front panel is actually change something in memory).

I'm pretty sure the instructions for the PiPD have it specified correctly. At least it is correct on my PiDP, and I don't think I my original panel was still packed away in boxes when I assembled it.

Regards,

Digby

--
You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/CABQ4%2Bi%3Dk_otVsy3oUVLFzaz9999aUWCJaxoZTW2ry%2B_PDZDK1w%40mail.gmail.com.

[oscarv]

Christian,

For the PiDP-11, switch orientation (push up or push down) is identical to the real PDP-11/70.

For the PiDP-8, the DEP switch is reversed versus the real PDP-8/I. On the PiDP-8, you push down on DEP, on the PDP-8/I, you push up on DEP. Reason for this: I expected people to put it in wrongly, as the authentic PDP-8 DEP switch is the only one that is mounted in reverse. It's something that people would tend to forget in the mental fog of soldering action, leading to loads of builders ending up having to desolder their DEP switch. So I chose to have DEP aligned just like all the other momentary switches. Not sure it was the right decision, but it would only cause more confusion to change it for new kits.

If you want the PiDP-8 to have the authentic (push up to DEPosit) behaviour: you'd solder in the white momentary DEP switch upside down, cut the trace from diode to the upper pin of the switch. Then, wire the bottom pin of the switch to the diode.

Kind regards,

Oscar.

[emt377]

From what I recall  (muscle memory?)   DEP=up   was standard on all 11s.

Or at least all proper 11s - the ones with console switches  :-)

[Shane Bouslough]

This is correct. Dep=up. 

-Shane 

-- 
Shane Bouslough

On June 28, 2019 at 8:13:30 PM, 'emt377' via [PiDP-11] (pid...@googlegroups.com) wrote:

From what I recall  (muscle memory?)   DEP=up   was standard on all 11s.

Or at least all proper 11s - the ones with console switches  :-)

--
You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/2dfba1e7-285f-483b-b260-e8251aa51669%40googlegroups.com.

[Christian Kuhtz]

Got it ;-) thanks, yes, I did my PiDP-11 correctly then, now opening the PiDP-8 up to rewire ;-)

--
You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/1da98bde-28ce-46fb-99ae-1dbd372d657e%40googlegroups.com.

[Christian Kuhtz]

Thanks everyone, super helpful!

Best regards,

Christian

To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/CACD9PUD4z9wwWEt7yZ%2BNa1zCf_S2D_%3D8r3Q-H2BJ4avDYYrftQ%40mail.gmail.com.

[Christian Kuhtz]

Flipped deposit switch, all better now ;-)