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Schematics for PDP 11/23 *** PLUS *** available somewhere ???

G

Gerardcjat

Experienced Member
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Feb 23, 2010
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40 Km South of Paris, France
Hello all,

I think I am going to join your wonderfull and very technical community :)
Sure, it gone be a good time !!

I very recently bought a "naked" PDP11/23 PLUS
Naked, because the ONLY card it has is the asynchrone com. card !!.
I will, I hope, fill it later but, by now, I am checking the power supply ( Reforming capacitors ... )

THE question :
- Where can I found the schematics for PDP 11/23 PLUS ???

I found schematics ( bitsavers ) for "standard" PDP 11/23, and at least for the PS, they are "close enough" to start the job but obviously, I would like the real ones, for later serious work ....

Any idea ???

Also, for far deep into the future ..... :D does someone have an 11/23 ( or close to ... ) connected to a "reel to reel" mag. tape ??
Is that more or less common ? and if so, with what magnetic tape drive, usually ?
 
The KDF11 User Guide is your friend! Download it and read it. Next start looking for a M8186 card, a M8044 memory card or two and last but not least the BDV11 bootstrap terminator card and your well on your way to the full Qbus experience! You wont have a 11/23+ but you will have the most common components for a working 11/23 PDP-11 and you will find that there are many here to help.
 
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RSX11M+ said:
Module M8189? [11/23+ CPU, 2 Serial Ports, Bootstrap ROM / Diagnostics]

First module identification please... is this what you have? (or did I misunderstand)

If so, this is the schematic.

Or are you saying you bought an empty chassis with only an ASYNC card? [if so you're ahead of me here Ray]
Click to expand...

Thanks for the replies, Fox.
English is NOT my native language, please pardon that !
May be I did not state it right.
RSX11M+ is absolutly right :
that is : Or are you saying you bought an empty chassis with only an ASYNC card? [if so you're ahead of me here Ray] ( That's what I wanted to say :D )

" so you are ahead of me" ??? Means that you too, would like an 11/23 PLUS chassis ( 19" rack WITH Power Supply ) ???

So back to the first question : For that chassis, and its P.S. I have schematics that are "close enough" **BUT** that are NOT EXACT ( Discrepensies already found in the "AC Box", AND, in the Power supply itself. )

BTW, I am still in the process of reforming the "big" capacitors ....
 
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I think we got the hint about a language barrier - [Ray [Qbus' name] got it first though - took me a little longer - so I was "behind"]

Ok, enough about language.


Let's take this one step at a time - you have a "BOX"... we need to identify it. Photos would be ok [front, rear & oblique please plus individual cards] or you can follow the links in my earlier post and see if you find anything familiar among them. I'm guessing the "empty chassis" link may match.
 
OK guys, and thanks !
Now that I know that Qbus's name is Ray ... of course I understand ( almost every things :D ).
Ok, just let me go downstairs, I will be back with "a lot of" DEC part numbers ....
 
Here we go :

What I got :

An empty PDP11/23 PLUS ( 19 " drawer / rack mountable )

Chassis is BC
Backplane is H9276-A
AC Input Box is H403-B
Power supply is H7861 Rev B

Only one card in it, which is ASYNC Com. Card M8028

It is very possible that this chassis has been "OFF POWER" for years ( even decade, I do not know )
That is why I am in the process of reforming the "big Input capacitors C1 / C2 "
Then after, I will test the PS on a dummy load ( Just bought the needed power resistors )

BTW, PS has one "bleeding" ( is that the correct word ?? ) resistor OPEN ( 20 K, 5 W ). I will fix that.

I have some "pretty close" schematics, but NOT the good ones.
I found already discrepansies at the PS level and at the AC Input Box.

Then, I also got :
M8067 QBUS Mos Memory card
and
M3189 "CPU card"

Both cards in an unkown state .... Should have been kind of spare parts BUT before or after use/replacement ? ( see what I mean ? )

THEY DO NOT BELONG TO THIS SYSTEM !!! Obviously they belong to an ( other ) PDP11/23
So I have to be very carefull before "throwing" them in this rack.

But, you will agree, I think, that I may have a sound base to (re) build an PDP 11/23 PLUS IF the cards are in working order !

First question to you, experts guys : What is the easyest way to know if the backplane is 18 or 22 bit addressing ??
18 bit is 256 K BYTE addressing
and I saw that some PDP11/23+ are 512 K byte capable what I "translate" as being 22 bit adress bus wide .... Am I right on this point ??
 
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One last point, to get a sound base ....

@RSX11M+ : "the "empty chassis" link may match"

This link goes to PDP 11/23 PLUS system manual ( correct ?? )

I had already found it, but many thanks anyway. I think it may be usefull to PRINT it, don't you think ?
Should become "almost" my Bible, PDP wise.
 
The M8067 is a Qbus memory card, depending on the two letters after the number it will be a “FA” 128K, “KA” 256K or a “LA” 512K card. The M8189 is a KDF11-BA 11/23+ CPU card. Sounds like you may have everything you need for a system.
The CPU card (M8189) is a quad with card that will go in the top of the system, the memory (M8067) is next and the Async card (M8028) will be last inserted only in the A/B slots, not in the C/D slots. Looking at the back of the system the slots are A, B, C and D and rows 1,2,3,4 and so on from top to bottom.
Throw the cards in the rack, they belong there!
 
Probably YES, but in a week or so.
No much time left for this projet right now.
I will take pictures when I will be back to it I.E. when I receive the power resistors ordered. ( for PS load test )
 
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