So I'm working on fixing some old code here. Found my balticon gaming
system disks from 1990 (yes, I used to drag a pdp11 and 4 terminals to
Balticon and other cons for computer gaming) and dungeon works on the
4.0 RSX version I was using but when I try to run it on 4.2 I get an
Error 4 at PC 162570.
I tried recompiling: RSXCMP works fine and compiles all the modules
however when I run TKB with the rsxbld I get a bunch of *DIAG* Segment
(root3, rooms, etc) has address overflow: allocation deleted.
What am I doing wrong today? The task builder file is:
dungeon/cp/fp=d.odl/mp
stack=384
libr=fcsres:ro
asg=sy:1:2:3:4,TI:5,CO:6
Reading the docs I see:
The Fortran-IV-Plus object time library must be merged into
the system library (SYSLIB.OLB). Further, the library must
be set up to invoke the short error text module ($SHORT) as
the default. Task building with a separate object time library
produces numerous errors; task building with a resident library
or the normal error text module produces an oversize task image.
This might be the problem, anyone remember how to put the short error
text module into syslib.olb? Hm. Maybe it is. Hm....
C
I'm trying to bring a pdp-11/83 back to working order. Challenge right now
is storage - I have RQDX3 and RD54 but the RD54 appears to be unserviceable
(never goes ready) and TQK50 with a TK50 which never gets to a stage of
allowing me to operate the handle to load a cartridge - the green LED
doesn't come on, the red LED is solid for a short time after power applied
but then flashes rapidly. I plan to go with an MFM emulator in place of the
disk, but would like to get a TK50 working as I have a lot of old stuff I'd
like to try reading off cartridges.
I have a spare TK50 drive, which behaves exactly the same. The TQK50 LEDs
suggest it passes diagnostics, and the boot menu recognises it and will
attempt to boot from it before saying there is no such drive. I don't have a
spare controller.
There is a lot of very detailed documentation for the TQK50/TK50 as far as
the electronics and interfacing is concerned but I haven't found much in the
way of information about the mechanical side. Are there common failure modes
for these drives when they've been stored for a long time? Last time they
were powered up is probably close to 20 years ago. Without much in the way
of test kit (I have multimeter but no scope) is there anything I might be
able to check easily?
Thanks,
Martin
Well, I put the VT52 back together, tightened all the bolts, plugged it
in, turned it on and enjoyed the silence. I can just barely hear the
transformer hum but that's about it.
Hooked it up to my PDT11/150, booted up RT11 and the display is
perfectly crisp and clear. Ran space invaders to check it out, no bugs
or errors and the screen updates perfectly.
Glad I got this working again. I'll take a look at that transistor, I'm
almost 100% positive the switching transistor is either leaking or going
bad. Either way I'll order a transistor when I have some time and put it
in eventually to see if it works. But to be honest the new regulator is
a thousand times better than the original discrete logic system.
So moral: If your VT52 goes nutty and the screen becomes a blur try
checking all of the voltages. An errant -12v will make the screen
unreadable at -15v and I'm guessing oddness on the other voltage levels
will do similar things as well. And don't leave it on for days, that's
probably what pushed the transistor over the edge, but I'm guessing it
has been crummy for awhile which is why I heard all that noise in the
high voltage circuit.
I feel like I accomplished something today. Thanks everyone for the help
and thoughts in getting this old girl to work again...
CZ
In fixing my PSU I managed to break the leads to the LED on the front of the
PSU, probably through metal fatigue.
I seem to remember people saying it is quite difficult to replace these,
mainly because you can't get them out without breaking the holder. Is that
right? Has anyone done this successfully and have any tips?
Are there any recommendations for a replacement? If I remember correctly the
LEDs used in those days were not as bright as modern ones and a modern one
would end up being much brighter because of the higher voltage maybe?
Thanks
Rob
A friend recently reminesced about the Monrobot, which we have discussed a
little bit lately, . . .
[Note: Unrelated to the Marilyn Monroebot on Futurama]
---------- Forwarded message ----------
Date: Wed, 13 May 2020 16:38:22 +0000 (UTC)
Subject: A trip down memory lane in the world of computers (I probably have
shared this with you in the past) from an email to another friend...
My high school... Erasmus Hall High School in Brooklyn...?? ?
listed as THE LARGEST PUBLIC HIGH SCHOOL IN THE WESTERN WORLD (I guess
they were trying to exclude China and India at the time) was the first in
NY City to get its own computer... in 1965.?? ??IT was a Monrobot XI 2000.
Regarding that Monrobot XI?? 2000...?? ?? ??made by the Monroe desktop
calculator company of that era...
Its main memory was a rotating magnetic drum, with 2K??
16 bit words of fast electronic storage.??
Cycle op time was 11 milliseconds.??
It used 16 bit words, and one wrote its machine language
using what was NOT called "Hexadecimal", but instead "Sexadecimal"
(Latin, not Greek prefix was used)?? numbers, and NOT 1-9 then A-F, but
rather 1-9 and then T-X.??
Storage was on punched paper tape.
I learned to program it so that I could optimize access to the rotating
drum memory and get three accesses (the max possible) per revolution of
the drum, as much as tripling memory access speed.
11 milliseconds means?? 100 cycles per second.?? ??Modern desktop PCs
operate at around 3,000,000,000 cycles per second.Compared to the 2,000
words of main system memory of the Monrobot XI, today's desktop PCs have
around 8 to 32 billion words of memory.
I programmed it?? (at age 14, in 1965) in machine language (the computer
teacher didn't know how to do that)?? ... wrote a program for it to allow
me to input and it to output to its printer a sequence of 3 strip tease
images I got from a printout at Columbia University where I was then going
to the Science Honors Program for high school kids, there. on weekends.
---------- Forwarded message ----------
I may be wrong about Erasmus Hall High School of
Brooklyn being THE first high school in NY City to get its own
computer. There is a reference elsewhere to Bronx High
School of Science kids being taught IBM 650 language in 1959
or so.
I suppose, if so, I could start splitting hairs and say that,
while the Monrobot XI and the IBM 650 were similar in many
ways, the Monrobot XI was a much more modern generation in
that it used solid state, where the IBM 650 used vacuum tubes.
I vaguely recall there may have been a Monrobot XI and a
Monrobot XI 2000, the latter having twice the system memory
(rotating magnetic drum) as the earlier model.
Those were the days. I recall boot-strapping in programs in
machine language from the front panel!
I loved that machine. I remember the delicious smell of the
high quality oiled paper tape! [Some paper tape was oil
impregnated, some was not).
The thing came with a Fortran compiler. You loaded your
source tape on one tape reader, then loaded in part 1 of the
compiler, and an intermediate tape was output. Then you
loaded that intermediate tape and part 2 of the compiler on
the tape reader, and a compiled program paper tape was
output. THEN you input the compiled program, and (if you
were very very lucky), it ran.
Everyone else including the teacher used Fortran ONLY. I did
most of my programming on it in machine (not assembly... I
hand assembled my programs) ... machine language.
15 years later I programmed a prototype "Bio-medical micro
computer" that incorporated the JUST MONTHS EARLIER released
Intel 8080 processor to examine electrocardiograms in real
time (interrupt driven) and identify abnormal beats. I
programmed it in machine language, too. Storing programs in
1702 EPROMs. Input was via 3 buttons cycling 7 segment LEDs,
and a LOAD and RUN button. And an analog input for the EKG
signal. Output was to EPROM programmer and to EKG strip
chart.
Damn thing actually worked, pretty much. As well as most
other efforts back in 1975, anwyay.
---marty
Wonderful: A few weeks ago I forgot to turn off my VT52 and left it
running for a day or two. Now the screen is filled with snow and it
looks like the text is all over the place horozontally.
Any tips or thoughts on where to start looking to fix? The keyboard
seems to be working as does the RS232 input (the snow on the screen
changes when the pdp11 talks to it)
Thanks!
Chris
Turns out the "The Director" tape reader I purchased last week was
defective and I got a refund. So I thought I'd try my hand at the FANUC
TAPE READER A860. I may need to make a serial cable (?) to connect from
the internal connector don't know yet. Or maybe the internal 50-pin port
>from the photos is for the punch. Don't know yet, thus the need for the
manual.
I checked bitsavers.org but there was no manual there, anyone here have a
PDF or URL of the PDF for the FACIT tape reader A860-0056-T020?
Thanks in advance.
Bill Degnan
>
> From: Bryan Longram <Driverless at protonmail.com>
> Subject: Wanting some help with a PDP-8/a
>
> I acquired a non-functional PDP-8/A several months ago and in that time
> I've replaced all the outwardly damaged parts and have gotten the machine
> to power on with no issues. However the problem I've been having now that I
> can't quite seem to pin down is that every time I power the machine the
> address field is displayed as 07777 and the value field is displayed as
> 7777. Attempting to change addresses or the value of the address doesn't
> work as I can enter the value just fine but upon entering the Load Address
> button it defaults back to being all sevens.
I am in the process of repairing three 8/a Programmer's Panels. Two panels
had bad ribbon cables. A good panel exhibited the same behavior as yours
when used with the bad cables. I was able to cut the keying peg off two IDE
disk cables to try as replacement cables. They IDE cables don't fit well,
but do work. I will make new replacement cables for all three panels.
--
Michael Thompson
I have a DS20E Alpha machine. It's pretty fully configured, with two 666
MHz CPUs, 4GB RAM and 4x10K SCSI drives. In other words, it's a real power
hog. It has three power supply modules installed, and if I understand the
configuration rules then at least two should be required to run the machine
and the third is a hot spare.
But, when do SHOW POWER at the SRM prompt, I get
P00>show power
Status
Power Supply 0 * BAD *
Power Supply 1 not present
Power Supply 2 not present
System Fan 0 good
System Fan 1 * BAD *
CPU Fans good
Temperature good
What? If I believe that then I have no functioning power supplies
installed?!? At this point I should mention that the machine boots VMS and
runs just fine.
Obviously something is not telling me the truth. Does anybody know what
would cause this? BTW, what do the red LEDs on the front of the power
supply modules mean? Is LED ON a good thing (i.e. power OK) or a bad thing
(i.e. fault)? FWIW, none of the LEDs on my three power supplies is on.
Oh, and it's right about System fan #1 - one of the fans is not running.
I don't know if it's seized up, or if it's related to the power supply
issue.
Thanks,
Bob
