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What did I do to my PDP-8 today.

You guys! Making a leader is trivia. Here is some copied and slightly modified code for punching the title into the paper tape, if that helps.
Code:
/ I used this as a start. The 1st three statements of LOOP1 were removed and
/ in their place I hardcoded the TITLE and and loaded it so as to work as the
/ keyboard entry did. I limited the entry to 9 characters, 6 for filename, 2 for
/ext and a dot. Maybe this helps?
        ADDR=20         /20 PUNCH, 40 TELETYPE
        TPLS=6006 ADDR
        TPSF=6001 ADDR
/ TAPE LABELER  SA=200, CORE=200-734
/ BY JOHN WILSON 05-JAN-85
/ MODIFICATIONS TO FONT BY DAVID GESSWEIN 13-APRIL-14
/ ECHO TYPED INPUT ON HIGH-SPEED PUNCH
        *200
LOOP1,  KSF             /WAIT FOR INPUT
        JMP .-1
        KRB             /GET IT
        AND P0177
        DCA TEMP
        TAD TEMP
        TAD M0141
        SPA
        JMP UPPER
        CLA
        TAD M0040       /CONVERT TO LOWER CASE
        TAD TEMP
        DCA TEMP
UPPER,  CLA
        TAD TEMP
        TAD M0040       /CONVERT SPACE::BACKARROW TO 00::77
        DCA TEMP        /SAVE
        TAD TEMP        /GET IT BACK AGAIN
        CLL RTL         /*4
        NOP             /(BUG FIX, REPLACING 7006/RTL)
        TAD TEMP        /*5
        TAD BASEM1      /ADD TABLE BASE -1
        DCA 10          /SAVE IN AUTO-INDEX LOC
        TAD M0005       /INIT COUNT TO -(# OF COLUMNS), CLEAR AC
        DCA COUNT
LOOP2,  TAD I 10        /GET NEXT COLUMN (AUTO-INDEX)
        TPLS             /PUNCH IT
        TPSF             /SPIN UNTIL DONE
        JMP .-1
        CLA             /AC=0 FOR NEXT TIME
        ISZ COUNT       /DONE ALL COLUMNS?
        JMP LOOP2       /LOOP IF NOT
        TPLS             /PUNCH ONE MORE COLUMN OF ZEROS
        TPSF             /SPIN UNTIL DONE
        JMP .-1
        JMP LOOP1       /BACK AROUND FOR NEXT CHAR
/ DATA (BESIDES LOCATION 10)
M0040,  -40            /-40 (OFFSET FROM BLANK TO 00)
P0177,  177
M0141,  -141           /(A)
TEMP,   0               /TEMP FOR COMPUTING INDEX INTO TABLE
M0005,  7773            /-5 (- # COLUMNS PER CHAR)
COUNT,  0               /COLUMN COUNTER
BASEM1, .               /BASE OF TABLE, -1
        DECIMAL
        0;0;0;0;0               /SPACE
        0;0;223;223;0           /!
        0;7;0;7;0               /"
        40;255;40;255;40        /#
        134;137;255;137;113     /$
        131;99;24;198;193       /%
        108;146;172;64;160      /&
        0;0;7;7;0               /'
        0;60;66;129;0           /(
        0;129;66;60;0           /)
        84;56;255;56;84         /*
        16;16;255;16;16         /+
        0;160;64;0;0            /,
        16;16;16;16;16          /-
        0;192;192;0;0           /.
        128;96;24;6;1           //
        126;161;137;133;126     /0
        132;130;255;128;128     /1
        194;161;145;137;134     /2
        66;137;137;137;118      /3
        12;10;137;255;136       /4
        199;137;137;137;248     /5
        126;137;137;137;114     /6
        1;1;249;5;2             /7
        118;137;137;137;118     /8
        70;137;137;137;126      /9
        0;96;96;0;0             /:
        0;128;96;96;0           /;
        16;40;68;130;0          /<
        12;12;12;12;12          /=
        130;68;40;16;0          />
        4;2;177;10;4            /?
        56;68;154;188;152       /@
        254;9;9;9;254           /A
        255;137;137;137;118     /B
        126;129;129;129;129     /C
        255;129;129;129;126     /D
        255;137;137;137;137     /E
        255;9;9;9;1             /F
        126;129;129;145;243     /G
        255;8;8;8;255           /H
        129;129;255;129;129     /I
        96;128;129;127;1        /J
        255;8;20;34;193         /K
        255;128;128;128;128     /L
        255;2;12;2;255          /M
        255;2;60;64;255         /N
        126;129;129;126;0       /O
        255;9;9;9;6             /P
        124;129;161;65;190      /Q
        255;25;41;73;134        /R
        134;137;137;137;113     /S
        1;1;255;1;1             /T
        127;128;128;128;127     /U
        63;96;192;96;63         /V
        127;128;112;128;127     /W
        195;36;24;36;195        /X
        3;4;218;4;3             /Y
        193;161;145;137;135     /Z
        0;255;129;129;129       /[
        1;6;24;96;128           /\
        129;129;129;255;0       /]
        4;2;255;2;4             /UP ARROW (^)
        128;128;128;128;128     /_
        0;1;2;4;0               /

        $

Thanks, Mike
 
BTW, I had to replace some of the power supply connectors in 8/e systems at LSSM recently. Mouser has the parts. Ping me if you would like the part numbers.

-Dave
I'm also facing this issue of discoloration of the +5V pin on the power supply connector. It seems likely to be a common problem with all 8/m systems. I'm seeing a worse issue with the quick-connect connection crimps at the ends of the wires that attach to the backplane.

@mcguire (Dave) could you share the connector pin and shell part numbers that you found at Mouser? I think we can all benefit from this.

I'd like to rebuild the cable between the power supply and backplane (both ends and wire) and also implement the fix that Roland has done in his PDP-11/10:
"Here is my 11/10, it has the same power supply as the 8/F or 8/M. I've added an extra set of wires between the 5V capacitor on the power and the backplane. Originally I had a voltage drop of 0.7v between the power and the backplane."
photo is in: https://forum.vcfed.org/index.php?threads/what-did-i-do-to-my-pdp-8-today.77577/post-1247620
 
I'm also facing this issue of discoloration of the +5V pin on the power supply connector. It seems likely to be a common problem with all 8/m systems. I'm seeing a worse issue with the quick-connect connection crimps at the ends of the wires that attach to the backplane.

@mcguire (Dave) could you share the connector pin and shell part numbers that you found at Mouser? I think we can all benefit from this.

Hi, these are the 8/e connectors, which I'm pretty sure (can't picture it right now and I'm not near one) it's different from the 8/m. But here's the 8/e connector info, for the H724 power supply:

TE Connectivity Commercial MATE-N-LOK

Power supply side:
Shell 1-171196-0
Pins 60619-1

Cable harness side:
Shell 1-163035-0 or 1-480276-0
Pins 60620-1

For these connectors, I recommend coating them with DeOxit before mating them. This will stave off the high-resistance problem later on.

-Dave
 
Hi, these are the 8/e connectors, which I'm pretty sure (can't picture it right now and I'm not near one) it's different from the 8/m. But here's the 8/e connector info, for the H724 power supply:

TE Connectivity Commercial MATE-N-LOK

Power supply side:
Shell 1-171196-0
Pins 60619-1

Cable harness side:
Shell 1-163035-0 or 1-480276-0
Pins 60620-1

For these connectors, I recommend coating them with DeOxit before mating them. This will stave off the high-resistance problem later on.

-Dave
Thank you! You're correct, the 8/m is different... it has 9 pins instead of 6. The 8/e part numbers got me in the ballpark and was able to find what I'm pretty sure are the 8/m connectors which are a cousin of the 8/e. I'm going to order shells, pins and sockets to confirm.

What I think is probably the 8/m Power Supply side, TE Internal #: 1-480274-0
https://www.te.com/usa-en/product-1-480274-0.html
uses the same 60619-1 socket terminals for 20 AWG to 14 AWG

and what's probably the 8/m cable harness side,
https://www.te.com/usa-en/product-1-480277-0.html
uses the same 60620-1 socket terminals for 20 AWG to 14 AWG

Phosphor bronze sockets and pins are the -4 versions.

There are Mouser "shop now" links from both of the above TE pages.

Tyco catalog/datasheet with technical details of shells, pins and sockets is here:
 
Thank you! You're correct, the 8/m is different... it has 9 pins instead of 6. The 8/e part numbers got me in the ballpark and was able to find what I'm pretty sure are the 8/m connectors which are a cousin of the 8/e. I'm going to order shells, pins and sockets to confirm.

What I think is probably the 8/m Power Supply side, TE Internal #: 1-480274-0
https://www.te.com/usa-en/product-1-480274-0.html
uses the same 60619-1 socket terminals for 20 AWG to 14 AWG

and what's probably the 8/m cable harness side,
https://www.te.com/usa-en/product-1-480277-0.html
uses the same 60620-1 socket terminals for 20 AWG to 14 AWG

Phosphor bronze sockets and pins are the -4 versions.

There are Mouser "shop now" links from both of the above TE pages.

Tyco catalog/datasheet with technical details of shells, pins and sockets is here:

Excellent, I'm glad to help. Thanks for digging up the 8/m connector part numbers; I've made a note of these. My 8/m is at home, not at LSSM, and it's a bit difficult to dig into as it's under a couple of S-100 chassis at the moment, but I'm pretty sure its power connectors are still ok. It runs and doesn't make any burning smells, anyway. ;) If you end up ordering these, please let me know if they fit ok.

-Dave
 
These days I get some equipement out of my basement, that was lasting there since some years. This beautiful 8/e was one of two machines from a shool. Only the relais was a bit sticky in the powersupply, after some knocking it was OK. The front was made by a DEC Professional, I think somewhere in the 90s.
The Frame is 8/e with two backplanes in it. The front is LED. But the switches are more like a PDP15 or PDP12.
Inside there are 2 8k Plessy Core cards, that only need one slot each. The two 4k DEC Core Ensembles need 6 slots.


IMG_5470.JPG


Have fun,
gnupublic
 
That is a very different 8/e front panel. The 8/i and the PDP-12 have rocker switches like those. The colors are similar to those used on the DECset 8000. Very unusual and rare.

Any idea what company the logo in the upper right is for? What comes to mind for me is something to do with nuclear power.
 
The sticker is only for mesuring temperature like the ones for wine bottles and aquariums. Nothing specific. I don't know why this was placed to the front.
 
.. The front was made by a DEC Professional, I think somewhere in the 90s. ..The front is LED. But the switches are more like a PDP15 or PDP12.

Have fun,
gnupublic
That's an impressive piece of work for a custom 8E front panel. Looks like the power and selector switches are DEC originals. I get the impression it could be an 8F (LED-style) front panel that needed toggle switches. He had some PDP-15 (or DECsystem KA10) ones handy?
 
Thought I'd join this thread. Working on getting ready for VCF. Decided to bring my 8/I this year. Fired it up and stuck memory bit. Swapped a G22x and good to go.

My DF32 wouldn't boot though and would read on first power on but quickly stop working. I'm using my DS32 emulator instead of trying to use the platter since they don't like power cycles. Traced it to my board which isn't giving the proper incrementing word address pattern. Touched it and behavior changed. Cleaned contact and re-soldered anything looking suspicious but now no change when touched and still not working. More false leads. Poked more and its just not doing what the VHDL says. Pulled out the programmer and read it back and it doesn't match and reads give different results. Reflashed the XC9572 and now all is well.

Does it mean I've been doing this too long if the stuff I made is now dying of old age? Programming file was from 2008 so only 14 years. Seems a little early to be loosing programming.

Next up was my Tek 611 storage monitor. It has a nice display and can be used store or non store. It died at VCF a while ago so time to fix. The storage screen glowed so assumed tube was good but later check of the high voltages and they are way off. Found a short between two windings on the high voltage transformer so its not going to be working for VCF. I had picked up another DEC branded one at a hamfest that was in rough shape. Little playing with adjustments and got the test pattern working ok non store. Store isn't working well. Tube likely near end of life for store. Need to poke at it some more.

A file dump on Bitsavers recovered more of DECUS-8-250 signal capture and FFT program for my AX08 so been working on recreating the missing storage definition and little bit of code tape that is still missing. Got it working and found the multiply routine had serious bugs. 0 * -1 = -2048. Other times zero give small non zero values. Many negative results were off by 4 and some other values had large errors. Fixed that and the sin table also had some wrong values and was truncated so fixed that. Will be showing it off at VCF.

Got more plans. Will see what gets done in time. Not a lot of time left.
 
I did (eventually) find those.

Hmm. Is it normal for me to have part 2 in the same file as part 1? I find the naming quite confusing when they do that. A grep for PART shows I have 1, 2, 3A, 3B, 4, 5, and 6 spread accross tapes 3, 4, and 5. But the tape labeled part 1 doesn't have a PART, just a trig table. And I don't have a tape 2.

Anyway, thanks!

Vince
 
I did some work on my Tennecomp Minidek TP-1371 which came with my 8/M. It was originally used in a Rotochem system. Unfortunately, I lack the two-board controller for it. Fortunately, I should be able to still read the tapes I've got either using Audacity and some decoding from there, or by using a microcontroller with a little analog-to-digital front end per the schematics I've got.

Album here:

My predicament is still finding foam pads to replace the deteriorated ones in each of my cartridges.

Edit: added more pictures to the album. Hopefully this will refresh it so they appear.
 
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Adhesive backed furniture pad felt might work - does the job for floppy drive backup pads. I think I have one of these Tenecomp drives too, with an interface for an 8/L or 8/I. Or not.
 
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