Hi,
>From: "Fred Flintstone" <iamvirtual(a)hotmail.com>
>To: cctalk(a)classiccmp.org
>Subject: Re: DEC LA36 Decwriter II
>Date: Thu, 26 Dec 2002 13:43:54 -0900
>Reply-To: cctech(a)classiccmp.org
>
>I guess I should have been more specific :-)
>
>I have what appears to be an OEM LA36. The label on the front says 'Data
>Terminal Mart'. On the back, there is a label from Digital which gives the
>model number as LA36DP. The processor board inside is made by Datasouth
>Computer Corporation (P/N 512000-2). There is an 8 DIPswitch located on the
>board. I do not have any documentation for this particular model and thus,
>I do not know what the settings should be on the switches. I do have user
>docs for an older LA36, but it does not cover my particular model.
>
>I am looking for information on the LA36, specifically the 8 dip switches.
Ok, you seem to have a third party controller in your LA36. Because DEC build a
real heavey-duty construction for the LA36, and let it print only with 30 cps.
many people and some companies thought it could do much better.
The few companies mentioned before put to the market several replacement-
controllers, making a LA36+ (mpnc) with a much better performnce, sometimes 150
or so cps, loadable fonts and/or pixel-graphics ect. The many people bought
those controllers and integrated them into their LA36'es and DEC-Fieldservice
didn't got tired of telling anyone that a terminal upgraded that way would
certainley disintegrate into its atoms "whitin months"... (I've never seen this
happen).
These 3rd-party controllers would completeley replace the original DEC-made
logic board that was attached to the innerside of the back-door, and was about
just as big as that door itself.
(mpnc = my personal naming convention)
So the DEC printset won't help you much with this, you should find a manual of
Datasouth, to get details on the dip-switches. (most likeley they set the
baudrate, and the switch in the keyboard has maybe got some other function.
>
>What I am trying to accomplish is to get the terminal console working on my
>PDP-11/10 (really it is a PDP-11/05) prior to getting my PDP-11/20 running.
>
That should be possible, 11/10+05 have only 20mA cuircuits. The 11/05 computer
is always the active party (=supplying current to the loop) on both Tx and Rx.
The baud-rate is made by a rather unstable pair of one-shot monostables. Use a
osscilloscope to set the time of this to either 26 or 35,5 microseconds.
You need 26 us for the selection of 150 (tap5) - 2400 (tap1) baud, or 35,5 us
for 110 baud on tap5 of the swich.
>
>When I hook everything up, the SCL on the PDP-11/10 has the expected
>voltages. When I connect it up to the LA36, the voltages are driven to near
>0v.
I think, thats normal, afterall when the terminal is idle, there will be no
current flow. Put your multimeter into mA-mode, and put it in series into the
loop. Use preferably a cheap passive arrow-meter, the cheaper it is, the better
the measurement. Alternativeley, you can also put a led somewhere in the loop.
create data-output, and see what happens
>I am not sure I have things hooked up correctly, or if there is a
>problem with the SCL. I used the docs I had for the older LA36 to connect
>my LA36DP. The connections I made were from T+ on the PDP-11 to R+ on the
>LA36 and T- on the PDP-11 to R- on the LA36.
Seems ok to me. (long time ago...)
(Beware however that the naming-conventions for ths 20mA current-loop were not
always consistent. There is no industry standard for this. I dont know how
Datsouth has named its connection-terminals)
If all this is ok, still nothing will happen if the baud-rate is unmatched
between 11/05 (rotary switch and trim-potentiometer on M7260) and probably
dip-switch and/or Keyboard-button or keyboard sequence on the LA36+
>When the LA36 is not
>connected, there is no voltage on the Transmit/Receive which I am presuming
>means the LA36 is in passive mode.
Ack.
>Voltages are present on the Transmit/Receive on the PDP-11 side,
>and I presume the SCL is in active mode.
Ack.
Hope you can solve this.
Frank
On 12/27/2002 02:48:31 PM CET G?nter Mewes wrote:
>
>today I was looking for some Z8000 Fans, to talk about experieces ...
>Are you interested ?
Yes, I am.
regards,
chris
From: John Lawson <jpl15(a)panix.com>
To: Glen Goodwin <acme(a)ao.net>
Subject: Re: VAX 11/780 anyone with some working experience out there?
Date: 12/25/2002 4:47 PM
> another, but no such luck... and I know plenty of folks who spent long
> years working in big machine rooms... 90+ dB all the time... no thanks.
Umm, 90+ dB? Can this be right?? That seems awfully loud. Is that typical for
larger machines?
Just one more thing to take into account before I seriously consider moving any
larger equipment in here . . .
Glen
0/0
From: Sellam Ismail <foo(a)siconic.com>
>So I guess I should open my reader up and find out which version it used
>in order to determine how to wire up my connector to the 6522?
>
Probably best. On the parts page 12-31 the IC's with the multiple #'s
are the ones that change between the versions (see the next page also).
One person interested in 20 ma LA36's, and I think an answer in error from
Don Maslin. Thanks for the information on the 20 ma question Kevin and Larry
I'm not sure if these units are 20ma loop - but from their history I'd
expect them all to be the same. The plug on the connecting cable is a DB25
female, and the wires go to pins 1 through 7. Models are; Datacom 400 (the
one which may work), 2 Datacom 1200's, and 1 Decwriter III. Does the pin
connection help with the 20ma question, or is there a simple test I can make
on the lines? I'm not sure from Kevin Hardy's letter if one could just
change the wiring - it sounds like it, but these may be OK already. I tried
to see if I could tell what the output driver is (as per Larry's comment),
but the board isn't very easy to see. There appears to be an output IC
labelled 7550 - is this a valid TTL number?
Don Woods
Message: 3
>From: Barry Moyer <barry.moyer(a)pason.com>
>To: "'cctalk(a)classiccmp.org'" <cctalk(a)classiccmp.org>
>Subject: DEC LA36
>Date: Tue, 24 Dec 2002 09:08:19 -0700
>Reply-To: cctech(a)classiccmp.org
>
>Don,
>
>I am in Calgary and I have a newer LA36, but I am looking for another older
>LA36 with a 20mA loop connection. You can contact me at 'iamvirtual at
>hotmail dot com' (replace at with @, dot with .)
>
>Thanks
>
>Barry
>
...
>
>Message: 9
>From: "Fred Flintstone" <iamvirtual(a)hotmail.com>
>To: cctalk(a)classiccmp.org
>Subject: Re: DEC LA36 units
>Date: Tue, 24 Dec 2002 10:46:02 -0900
>Reply-To: cctech(a)classiccmp.org
>
>Don,
>
>I am currently looking for an older LA36 which has a 20mA connection (I need
>it to connect to my ancient PDP-11s). Do you know the model numbers for the
>LA36?
>
>Thanks.
>
>--Barry
>
>.
>
>Message: 15
>Date: Tue, 24 Dec 2002 15:59:09 -0800 (PST)
>From: Don Maslin <donm(a)cts.com>
>To: cctalk(a)classiccmp.org
>Subject: Re: DEC LA36 units
>Reply-To: cctech(a)classiccmp.org
>
>No Barry, sorry, but Dec printers are outside my area of knowledge.
>
> - don
Message: 4
Date: Thu, 26 Dec 2002 09:39:19 -0700
From: Kevin Handy <kth(a)srv.net>
To: cctalk(a)classiccmp.org
Subject: Re: DEC LA36
Reply-To: cctech(a)classiccmp.org
Barry Moyer wrote:
>Don,
>
>I am in Calgary and I have a newer LA36, but I am looking for another older
>LA36 with a 20mA loop connection. You can contact me at 'iamvirtual at
>hotmail dot com' (replace at with @, dot with .)
>
>
I believe that the 20ma current loop was available for all the LA36's.
It was just a different cabling option, bit a 'new' or 'old' version thing.
You could buy the 20ma current loop with your LA36, or later as
an option to change an existing one from RS232 to 20ma.
Message: 13
From: "Truthan,Larry" <truthanl(a)oclc.org>
To: "'iamvirtual(a)hotmail.com'" <iamvirtual(a)hotmail.com>
Cc: "'cctalk(a)classiccmp.org'" <cctalk(a)classiccmp.org>
Subject: DEC LA36 Decwriter II
Date: Thu, 26 Dec 2002 16:42:02 -0500
Reply-To: cctech(a)classiccmp.org
I have the engineering prints in the LA 36 Decwriter II
LA36 (MPC5) sheet 5 of 8 shows 20 ma RECIEVE on J3 pin 7(+) and Pin 3(-)
bridged by a 3.3 volt zener D4 746A feeding a 4N26 (E43) opto-isolator
which drives a MXAA05 (Q4) driver transitor which has its collector on J4
pin 2 "S.I." (serial in)
20 ma TRANSMIT is on J3 Pin 5(+) and Pin 2(-). These pins are bridged
by a 1N4004 diode D6. This diode also is parallel to the
emitter/collector of Q2, an A05. which is driven by another 4N26
opto-isolator (E47). S.O. is J4 pin 4. It is driven by a 7404 inverter
(E62)-(Input is 7404 pin 3 connected to the diode cathode of the
opto-isolator, output is 7404 pin 4, which connects directly to J4 pin 4,
"S.O." serial out)
Sincerely
Larry Truthan
Finding old computers at the second-hand stores is getting difficult now but
I did goto one place and look through some software boxes they had. Lots of
DOS based stuff and ... OS/2 ! I got:
warp server
IBM training book and VCR tape for 2.1
warp 4 with mic
faxworks pro
galactic civilizations still wrapped
warp connect
DB2 single user
hyperaccess
OS2 system sounds
IBM attachpak for OS/2
I left behind warp red box but I'm glad I found it all.
--
Antique Computer Virtual Museum
www.nothingtodo.org
I am looking for this pretty rare printer - a SWTPC PR-40. Am offering
a $200 reward for information leading to a purchase.
Rick Crandall
rick(a)jelcoventures.com
