[cctalk] Re: ADM3a screen rot.

[Fritz Mueller via cctalk]

> On Jan 29, 2024, at 9:54 AM, William Sudbrink via cctalk 
>  wrote:
> ...the anode cap on the leaking CRT had gone rock hard and there was a small 
> "streak" on the back of the CRT that looked like the plastic that it was made 
> of had released some sort of oil…

Often times dielectric grease is used around anode caps, and it’s not unusual 
to see streaks like this.  Usually harmless, but you can clean it up and 
replace/freshen it if you replace the hardened rubber cap.  Be careful with 
such cleaning on the tube, though — depending on the tube, there may be an 
external aquadag coating which you won’t want to damage/remove.

—FritzM.

[cctalk] vt220 firmware source?

[Fritz Mueller via cctalk]

Hi folks,

I’m working on a vt220 debug/repair and have gotten to the point where I need 
to trace firmware execution at boot.  I’ve managed to dump the proms (close to 
but slightly different from the versions in Lars’ GitHub) and the 8051 internal 
rom, and can load and disassemble these with the s51 simulator.  I also have an 
HP 1660 logic analyzer successfully configured and clipped up to capture 
instruction traces.

I’m about to dive in to commenting the disassembly listings, but figured I’d 
ping here to see if anybody might have done this already in case I wouldn’t 
have to start from scratch?

   thanks much,
  —FritzM.

[cctalk] Re: Vintage Computer Fest Midwest "DECnut" pizza party

[Fritz Mueller via cctalk]

> On Sep 6, 2023, at 12:48 PM, Paul Koning via cctalk  
> wrote:
> 
> The weird case of the 11/05 is because the general registers are assigned 
> addresses 177700 through 177707 for R0 through PC, so R1 is at 177701 even 
> though it's a word wide.  On most models those addresses only work from the 
> operator console, but on the 11/05 they are also visible from the program.  
> And by special microcode hack ("just because they could", says ABC) if the PC 
> is in that range it increments by 1.


This was on the tip of my tongue because I was actually just debugging these 
very bits of microcode on a GT40 (which Scott Swazey will be demoing at VCFMW 
running “Lunar Lander” if it survives the journey there by car!)

The ALU B-leg input in the data paths on this CPU has a selection to generate 
constant +1.  In the usual cases, where the microcode needs +2 to be added to 
something, the additional +1 comes from a microcode field bit and is added in 
at the ALU least-significant-bit-slice carry input.  There is additional 
circuitry to inhibit this carry input in special cases like internal register 
address decodes, etc.

On our GT40, we had a microcode PROM failure which took out this very carry 
source bit.  Thus our GT40 PC was incrementing by just one _incorrectly_ in 
most cases where it should have been incrementing by two.  Quite a coincidence 
that your question came up soon after dealing with this :-)

—FritzM.

[cctalk] Re: Vintage Computer Fest Midwest "DECnut" pizza party

[Fritz Mueller via cctalk]

> On Sep 6, 2023, at 10:08 AM, Paul Koning via cctalk  
> wrote:
> "On what model and under what circumstances will the PC increment by 1?"

At least true on a KD11-B when executing code out of the memory-mapped register 
file :-)

(I just happen to have been wading through one of these a couple weeks back…)

—FritzM.

[cctalk] flipchip cleaning and pin corrosion inhibition

[Fritz Mueller via cctalk]

Hi folks,

I’ve been picking my way through a PDP-8/L restoration lately.  I’ve found that 
everything in the machine is covered with a uniform layer of dark “soot” 
(enough to blacken your hands while working with it) which I would like to 
clean up.  Perhaps the “soot” is actually from a decomposed air filter, as I 
don’t imagine this machine was operated in a smoky environment, and there is no 
smoke odor.

I usually use 99 IPA and cleanroom wipes for spot cleaning these sorts of 
things, but in this case there is so much of it that I feel that would just 
push the soot around rather than clean it off.  I think some sort of actual 
rinse would be needed here.

I’ve been eying the dishwasher, for the subset of flip chips that that are just 
DIP logic, carbon comp resistors, and ceramic bypass caps, anyway.   But I 
haven’t been brave enough to try that yet...  Most of the logic here has date 
codes to ’68 or ’69, so I’m inclined to treat it gently.  Any suggestions for 
approaches to clean this up?

Follow-on question: the majority of the legs on these old DIPs are showing what 
I’d call “moderate” corrosion — nothing looks like it is in danger of being 
eaten all the way through, but the process is underway.  I was wondering if 
something like a light shellac or other inhibitor could be brushed over these 
pins to at least slow their inevitable demise?

I did purchase and build out one of Vince’s flip chip tester kits, and have 
found it super useful for this project.  Of the large percentage modules that 
have test vectors supplied, most have tested fine.  Three M216 flip-flop 
modules and one M113 nand module were flagged for repairs this way.

Advice appreciated, as always!

cheers,
   —FritzM.

[cctalk] Re: DLV11 M7940 SLU header wire colours?

[Fritz Mueller via cctalk]

> On Dec 21, 2022, at 7:16 PM, Steve Malikoff via cctalk 
>  wrote:
> 
> For a DLV11 EIA serial connection, I am about to wire up a fly lead cable to 
> go from an M7940 SLU (no dash version) 40-pin header to a DB25P … I could use 
> any colours but I'd really like to use the original colours for the above …

The BC05C cable is described in full, including wire colors, in the docs for 
the Unibus DL11 (for example, PDF page 21 of the engineering drawings at 
http://www.bitsavers.org/pdf/dec/unibus/DL11_schem_Mar78.pdf, or table 3-6 on 
PDF page 34 of the user manual at 
http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/DEC-11-HDLAA-B-D%20DL11%20Asynchronous%20Line%20Interface%20Manual.pdf)

Specifically, for the pins asked:

J - receive data - orange/white
F - transmit data - white/blue
E/M - interlock - red

The ground wiring is a bit involved:

Pin 7 on the D-sub is connected multiple:

- cable shield to Berg B
- brown/white to Berg UU
- black jumper to D-sub pin 1

…and pin 1 on the D-sub is connected multiple:

- cable shield to Berg A
- blue/white to Berg VV
- black jumper to D-sub pin 7

[cctalk] Re: Great Vintage Computer Heist of 2012

[Fritz Mueller via cctalk]

> On Oct 19, 2022, at 6:16 AM, Paul Koning via cctalk  
> wrote:
> ...a couple of years ago I wrote an article about the invention of FM radio, 
> in Holland in 1919 (no, not by Armstrong in the USA in the late 1920s).

That sounds interesting, Paul  — I’m only familiar with the usual USA-centric 
Armstrong lore.  Is your article available to read online anywhere?

—FritzM.

[cctalk] Re: Connecting a physical terminal via LAN to Serial Port

[Fritz Mueller via cctalk]

> On Sat, Jul 30, 2022 at 10:23 PM Ali via cctalk  wrote:
> So I am wondering if there is a box that provides a telnet CLIENT to a
> serial port device? I.E. a box smart enough that handles the telnet client,
> LAN functions, and terminal emulations internally and then provides a text
> based interface through a serial port that is compatible with my physical
> terminal?


> On Jul 31, 2022, at 12:51 PM, Glen Slick via cctalk  
> wrote:
> You can do what I believe it is that you want with any Digi
> PortServer.

+1 for the Digi Portserver for this application.  I recently grabbed one off 
eBay, because I have a number of vintage terminals here which I would like to 
“crossbar” to a number of vintage computers with serial terminal support, and 
also provide both telnet out (vintage terminals telnet to modern systems) and 
in (LAN or WAN terminal emulator clients to serial ports on vintage systems).  
The Portserver looks like it is going to do this job nicely.

The only feature it doesn’t appear to have which I would like to have is 
“rotaries”, allowing automatic selection of an idle serial port from a group 
when connecting to a back end system that supports multiple serial lines.  But 
it was a lot more affordable used than the Cisco equivalents.

—FritzM.

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 26, 2022, at 2:19 AM, Noel Chiappa via cctalk  
> wrote:
> So, either (console halt, or a HALT instruction) will cause the identical
> response in the processor; see Section 4.10.3 "Halt Grant Requests": the CPU
> sends HLT GRANT to the console, which returns SACK. As long as SACK is
> asserted, the processor waits with its clock inhibited:

Ah, interesting!  I had no idea the console(s) used SACK to interact with the 
CPU in this way.  That’s a useful tidbit to tuck away for future reference.

> If there's a broken grant chain, then as you originally pointed out, the M9302
> will jam SACK on. The M8264 could not even be there, and nothing would be any
> different. Same thing if the CPU asserts a grant in response to a now-removed
> interrupt request: the M9302 will jam SACK on, etc, etc.

Perhaps the intent was to always use a non-turnaround far side terminator in 
configurations with an M8264?

cheers,
   —FritzM.

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 24, 2022, at 8:24 PM, Noel Chiappa via cctalk  
> wrote:
> … at first I thought that maybe you were thinking of the M7850 Parity 
> Controller (which is
> actually a memory option, not KD11-E/EA specific; more below), but that's a
> dual card.

Yes, I was thinking of the M7850, but I had forgotten this was just a dual card!

I think I had come to think of it as a CPU option because at some point during 
the /34 restoration that I did last year I got to the place of “oh, I needn’t 
bother trying to running the parity MAINDECs because I don’t have an M7850”, 
which felt sort of like “I needn’t bother trying to run floating point MAINDECs 
because I don’t have floating point...”  So alas, nothing exotic for you here, 
Noel -- just some sloppy thinking on my part :-)

> The complication was that when I powered the machine on, it turned out that
> something was asserting SACK when the machine was halted; if I put it into a
> 'BR .' loop, that goes away.

That is quite interesting, and not what I would have expected!

> Looking at the KY11-LB manual, it does in fact assert SACK (after it has sent
> the KD11 a 'halt request, and receives a 'halt acknowledge'), to recognize
> the CPU's acknowledgement of the halt request.

I ran into this when I started using one of Jeorg’s “Unibone” cards with my 
/34.  When the Unibone is in place and jumped to take grants, those grant 
chains are open at power up until the Unibone’s own control software can boot.  
So after power on my machine (w/ KY11-LB) would be jammed and inoperable from 
the front panel until the Unibone was booted.

> The thing that's puzzling me is that the M8264 seems to exactly replicate the
> functionality of the M9302, with an 'unused' bus grant being turned into a
> SACK. So I don't understand the point of the M8264.

I think the only difference would be that since the M8264 is timer based, it 
doesn’t need the intact end-to-end path required for turnaround.  So your bus 
won’t lock even if you have a broken grant chain or a poorly behaved or hung 
device eating grants.  I think my /45 has this built-in (will check later).  I 
would *guess* that the M9302 was just a “poor man’s SACK timeout”, and the 8264 
was offered later to shore that up to a real timeout for applications where it 
mattered?

cheers!
—FritzM.

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 21, 2022, at 10:29 AM, Fritz Mueller  wrote:
> Also, in taking a look this morning at the M9302 schematic around page 70 in 
> the commonly available 11/34 engineering drawings set (rev B, Sep 76), there 
> appears to be a mistake!  The output of the SACK turnaround circuit is 
> annotated here BUS SACK H, but I’m almost certain this should be BUS SACK L…  
> May be worth a look for other versions of the M9302 drawings to verify this.

And indeed -- the rev D, Jul 77 M9302 drawing has this annotation corrected to 
BUS SACK L.

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

>> From: Fritz Mueller
>> I think you are thinking of the M9302, Noel: a far-side terminator card
>> with integrated SACK turnaround?

> On Feb 21, 2022, at 7:19 AM, Noel Chiappa via cctalk  
> wrote:
> No; the M8264 Sack Timeout module. What's an M8264, you say? ...

Ah, quite interesting, didn’t know about that one!  The KD11-E is pretty bare 
boned...  Parity handling was also a quad “add on”.

> So if i) a device requests a grant, and then drops the request at _just_ the
> right time (so a grant gets sent out when there's no device waiting to grab
> it), and ii) there's a break in that grant line (maybe a missing grant
> continuity card) before it gets to the M9302, which can turn it around as a
> SACK , then ... the KD11-E CPU will hang!

One small elaboration here: grants on the UNIBUS, unlike everything else, are 
active high.  So I believe a broken grant chain with an M9302 in place on the 
far side results in the grant being pulled up at the M9302, and then continuous 
assertion of SACK, hanging the processor straight out the gate.

Also, in taking a look this morning at the M9302 schematic around page 70 in 
the commonly available 11/34 engineering drawings set (rev B, Sep 76), there 
appears to be a mistake!  The output of the SACK turnaround circuit is 
annotated here BUS SACK H, but I’m almost certain this should be BUS SACK L…  
May be worth a look for other versions of the M9302 drawings to verify this.

  cheers,
 —FritzM.

More VT52 HV

[Fritz Mueller via cctalk]

So, having pulled the CRT now , I was surprised to see that the ground braids 
seem to be held against the aquadag by only the pressure from a couple foam 
blocks!   In my unit these aged foams are deformed and brittle.  This would 
seem a good thing to add to the check list for looking at these…

I wonder if this explains why many of these I encountered back in the day in 
university terminal rooms and such were suffering from HV “snaps”?  I had 
always assumed it was just dust / grime / spilled cokes… :-)

Also, after a closer look, I’m surmising the red goo around the anode cap to be 
dielectric grease put there on purpose, and not degradation of the cap itself.

—FritzM.

Re: DEC VT52 CRT anode connection

[Fritz Mueller via cctalk]

> On Feb 20, 2022, at 10:27 PM, Fritz Mueller  wrote:
> I’ve begun some work on a VT52 ... is there a way to detach the HV anode lead 
> at the board side (does the white “cap” come off the lead connector?)

Well, just answered my own question — went back and tried to be a little more 
assertive, and yes, the white cap is in fact just a pressure fit on the black 
anode connector at the board.

DEC VT52 CRT anode connection

[Fritz Mueller via cctalk]

Hi folks,

I’ve begun some work on a VT52, and need to get the power supply board out onto 
my bench for some work.  For those who have been in here before: is there a way 
to detach the HV anode lead at the board side (does the white “cap” come off 
the lead connector?)  Or is the only option to unclip at the CRT itself?

They don’t make it easy to get to the anode cap in this terminal — one has to 
pull the whole tube, with the power supply board in tow.  After doing this for 
an inspection, I find the anode cap looking little brittle and covered with 
some red, oily “goop”…  I’d rather just leave that alone and detach from the 
board side if it works that way?

cheers,
   —FritzM.

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 19, 2022, at 10:51 AM, Noel Chiappa via cctalk  
> wrote:
> The -11/34 (not the /34A) has something unusual for grant timeouts, but I
> forget the details. I'll look it up.

> On Feb 19, 2022, at 12:11 PM, Fritz Mueller  wrote:
> I just did an 11/34 restoration last year, so this is fresh in mind — I think 
> you are thinking of the M9302, Noel: a far-side terminator card with 
> integrated SACK turnaround?

A few additional details, in case it is helpful:

IIRC, the 11/34 doesn’t have SACK timeout implemented in the CPU cards (the 
/34A did add this, however.)  So without an M9302 on the far end of the bus, 
the CPU could hang in a situation with an unacknowledged grant (which I think 
would be somewhat rare, but possible).  I believe it is possible to boot an 
11/34 at least as far as a ROM boot monitor with a non-SACK (M930 or such) 
terminator on the far side.

An 11/34 with a M9302 SACK terminator _will_ hang, though, with a broken grant 
chain — the floating grant will trigger the M9302 to continuously assert SACK 
locking the bus.  “Better” CPUs, which used SACK timeout instead of 
turn-around, were more robust this way.

Incidentally, I think the 11/34 was contemporaneous with, and usually found 
with, the slightly earlier M9301 ROM terminator on the near side, rather than 
the later M9312, though both should work fine.

cheers,
—FritzM.

Re: Is The M9312 Boot Module Essential?

[Fritz Mueller via cctalk]

> On Feb 19, 2022, at 10:51 AM, Noel Chiappa via cctalk  
> wrote:
> The -11/34 (not the /34A) has something unusual for grant timeouts, but I
> forget the details. I'll look it up.

I just did an 11/34 restoration last year, so this is fresh in mind — I think 
you are thinking of the M9302, Noel: a far-side terminator card with integrated 
SACK turnaround?

   —FritzM.

Re: RK11-C indicator panel inlays?

[Fritz Mueller via cctalk]

> On 12/6/21 5:50 PM, Mike Katz via cctalk wrote:
> For other boards without gold fingers where would you recommend and how 
> expensive for omnibus size boards?


> On 12/06/2021 6:33 PM Jon Elson via cctalk  wrote:
> I've been using PCBway in China. Usually, the DHL shipping is more expensive 
> than the boards themselves. Larger boards will be less than US $20 each, if 
> you get a few copies made.

> On Dec 6, 2021, at 5:52 PM, Will Cooke via cctalk  
> wrote:
> Another good option is jlcpcb.com in China.  They are very similar to PCBWay. 
>  I and others I know have been very pleased with them.

I’ve had good experiences lately with both pcbway and jlpcb.

Re: PDP-11/70 Boards

[Fritz Mueller via cctalk]

> On Dec 5, 2021, at 1:37 AM, Rob Jarratt  wrote:
> I don't see the Kunkin unit for sale except for a couple of items on ebay 
> from China. I am really reluctant to buy anything at all from China. I 
> couldn't find a manufacturer site for them, and I was wondering if there are 
> alternatives since they don't seem to be particularly available.

Yes, just about any programmable DC load in this class will suffice.  It’s just 
convenient to be able to punch in current or power limits, dial them up and 
down, and have everything including fans, thermal management, etc. in one 
compact package on the bench.

At the time I was looking, the Kunkin, while yes, from China, had a lot 
hands-on reviews on YouTube.  So I just went ahead with that.  Worked out okay 
for me, but one kind of annoying thing is the banana jacks on the five-way 
binding posts don’t seem quite standard (!) — I will probably change out the 
posts on mine.

Re: PDP-11/70 Boards

[Fritz Mueller via cctalk]

> On 12/5/2021 3:37 AM, Rob Jarratt via cctalk wrote:
> Thanks for the tips. The transformer that drives the bricks is a real beast.  
> Did you find an alternative more convenient way to power them on the bench?

No, I just used the big transformer, since I needed to bench and disassemble 
the H742s themselves for cleaning, inspection, and repairs anyway.

Re: PDP-11/70 Boards

[Fritz Mueller via cctalk]

> On Dec 4, 2021, at 3:57 PM, Rob Jarratt via cctalk  
> wrote:
> What kind of load tester are you looking to buy? I have an 11/45 which I need 
> to test the power supplies on too.

I picked up a Kunkin KP184 this last year, and it does nicely for testing those 
brick regulators and the power control boards in isolation (a bit more 
convenient than the old light bulb or power resistor approach.)

Some of the large electrolytics in those bricks will likely have dried out.  I 
disassemble and “reform" these with a bench supply and current limiting 
resistor on any of these bricks I have not yet personally serviced (Yes, I know 
the reforming thing is controversial for some.  I think its safe to say it at 
least doesn’t hurt anything :-)

Check the big bridge rectifiers carefully; I’ve seen a few of those cracked or 
toasted.

It’s also been my experience that beyond the bricks that are dead or fail at 
the start, some smaller fraction will also let go after the first few hours of 
continuous operation.  The don’t tend to fail with fireworks — you’ll generally 
get a slowly increasing whiff of magic smoke so generally plenty of time to 
shut things down.

The operation indicator bulbs on these seem almost always dead.  You can sub 
CM7381 for the +5V regulators, and OL-6003BP for the -15V.

Last, if you have H742 supplies on your 11/45, be sure to check the small 
muffin fan above the power control board. It is quite common for parts of the 
internal wiring harness to rub up against these and stall them out, eventually 
leading to a fried controller board.

Good luck!  Good winter time project :-)

—FritzM.

Re: PDP-11/70 Boards

[Fritz Mueller via cctalk]

> On Nov 30, 2021, at 7:17 PM, Jay Jaeger via cctalk  
> wrote:
> The issue is (I think) that the ExpressPCB software can only be used to 
> create files to order boards from them


> On Nov 30, 2021, at 4:31 PM, Paul Koning via cctalk  
> wrote:
> You're right, they say so in the FAQ.  And it is the reason I don't use them.

Oh, I hadn’t realized they have the whole lock-in thing going; that’s kind of 
obnoxious!

> My current answer is KiCAD which is open source and somewhat more powerful 
> than Eagle (without the hassles).

KiCAD is pretty nice these days.  A friend also recently introduced me to jlpcb 
and pcbway, and the prices and turnaround times from both of these board 
houses, even for very small runs, are amazing!  jlpcb will also do assembly of 
many stocked surface mount parts at very reasonable prices.

  —FritzM.

Re: Looking for tips debugging DEC TC01 controller

[Fritz Mueller via cctalk]

> On Nov 23, 2021, at 3:17 PM, Josh Dersch via cctalk  
> wrote:
> I picked up a TC01 in trade (for a TC08) a couple of weeks back and this
> past weekend I got it hooked up and powered up with my PDP-8/I + TU55
> transport.  I've been debugging it and have solved a couple of issues but
> the current one has me stumped and I'm looking for advice, hoping I
> overlooked something obvious...

Any updates here, Josh?  I’m not familiar enough with 8’s or their peripherals 
to offer any relevant suggestions, but I’m curious to hear what you find and 
how you crack it!

—FritzM.

Re: PDP-11/70 Boards

[Fritz Mueller via cctalk]

> I built mine from a layout on Tom Uban’s site: 
> http://www.ubanproductions.com/museum.html 

> Did you use that directly with ExpressPCB and order from ExpressPCB or did 
> you convert to more standard gerbers?

I just went with ExpressPCB for minimal hassle, but you could probably get it 
cheaper from other board houses these days.  For my KB11-A + FP11-B, which run 
asynchronously, it was handy to build up two of these.  Also useful for the 
RK11-C.

  —FritzM.

Re: PDP-11/70 Boards

[Fritz Mueller via cctalk]

> On 11/30/21 10:06 AM, Noel Chiappa via cctalk wrote:
> From the blog of someone who got a KB11-A working, you'll really need KM11
> cards...

> On Nov 30, 2021, at 10:59 AM, Guy Sotomayor via cctalk 
>  wrote:
> I do still have KM11 boards and some overlays (I'd have to check to see if I 
> have the appropriate overlays for the 11/70).  I don't unfortunately have any 
> light masks or full kits.

I built mine from a layout on Tom Uban’s site: 
http://www.ubanproductions.com/museum.html 
.  I have found the single long 
board form factor convenient, but they don’t have nice light dividers and 
overlays like Guy’s.

Agreed that at least one of these, as well as a hex extender card, are 
absolutely essential if you need to debug CPU/MMU/FPU cards (which, given their 
age, is nearly guaranteed unless you are getting them pre-checked/repaired from 
another restorer.)

 —FritzM.

Re: Looking for manual for MDB MLSI-LP11

[Fritz Mueller via cctalk]

> On Oct 26, 2021, at 12:21 PM, Nigel Johnson Ham via cctalk 
>  wrote:
> Does anybody have any sources other than bitsavers and vcf?

Hi Nigel,

I have hardcopy of a 15 or so page loose leaf manual for “MDB PDP-11 LINE 
PRINTER CONTROLLER (CENTRONICS INTERFACE)”, and believe I also have the 
matching quad-height board in my stores.

The manual has pinouts and a six or seven page “theory of operation” section 
with timing diagrams and block diagrams, but no actual schematics.

It claims toward the end that “The MDB PDP-11 Line Printer Controller is 
completely compatible with DEC diagnostic software.  Use that software to 
verify correct operation and for trouble analysis.”

I would be happy to scan this later this evening and send you a copy if that 
would be helpful?

  —FritzM.

Re: Unix or BSD for Dec PDP 11/34 and 11/45

[Fritz Mueller via cctalk]

A fully-populated 18-bit address space on the /34 and /45 is only 128K words, 
which seems like a pretty tight fit for a TCP stack with practically sized 
buffers?

I had always sorta assumed DELUA/DEUNA were only practically useful for TCP on 
extended Unibus machines (/70, /44, /24, etc.) but I could certainly be wrong 
on that assumption!

--FritzM.

DEC BA11-K noisy fans

[Fritz Mueller via cctalk]

Hi all,

I've been working on a BA11-K PDP-11/34 lately, and wow it sure is a noisy 
thing...

On my '11/45, the "Boxer" fans were easily disassembled via a cir-clip, and 
could then have their bearings cleaned/relubed (or worst case replaced).  Fan 
maintenance quieted down the /45 a good bit.  But these larger 6" Amphenol 
units don't look quite as easy to get in to...

Is the plastic rotor on these just a press fit?  Any tricks to getting in there 
for maintenance?  Or are these "you have what you have" and the only option if 
unsatisfied with their current performance to replace them entirely?

   cheers,
 --FritzM.



 

Re: Replacement for Foam Filter for PDP 11/24

[Fritz Mueller via cctalk]

> On Sep 4, 2021, at 10:42 AM, Rob Jarratt via cctalk  
> wrote:
> Another query. The foam filter that sits in the front of my 11/24 CPU is
> clearly badly degraded and needs to be replaced. What do people replace this
> kind of stuff with? I guess it mustn't be too fine, this mesh seems quite
> coarse.

Hi Rob,

FWIW, I've used 3M Filtrete (‎FAPF-UCTF2PAMZ) for this application on an 11/34. 
 It seems I tighter weave than the old foam, but is designed for pretty high 
airflow and seems to work well.

It's about 1/8" thick, slightly compressible, easily cut to size w/ scissors, 
and adheres well to velcro hook tape.

   cheers,
 --FritzM.

Re: Ultrix-11

[Fritz Mueller via cctalk]

> On Aug 25, 2021, at 10:16 AM, Paul Koning via cctalk  
> wrote:
> I have near zero PDP-11 Unix experience, but I remember one flavor (BSD 2.11 
> ?) which set the top bit in its alleged ASCII output, which of course would 
> break any terminal expecting actual 8 bit coding.

I discovered working with Unix V6 on my '11/45 that its tty output driver is 
hard coded to always cook bit 8 as a parity bit, for any character where bit 8 
is not already set (see Lions, line 8522).

  --FritzM.

Re: howto bitsavers BASIC-11 v2 disk image under simh

[Fritz Mueller via cctalk]

> On Aug 12, 2021, at 3:31 PM, Glen Slick  wrote:
> If I translate the logical
> sector order RX-02 disk image back into a physical sector order disk
> image (dealing with track shifting, sector interleaving, and track to
> track sector skewing) then RT-11 on SIMH is happy with the disk image.

Ah, interesting...  Where's the best place to look for more information in the 
RX02 RT-11 logical/physical mapping?

Glen, if you wouldn't mind sending me a copy of your resulting simh-compatible 
image, I'd be happy to post it in an upcoming blog article for others who might 
find it useful as well...

cheers,
  --FritzM.

Re: howto bitsavers BASIC-11 v2 disk image under simh

[Fritz Mueller via cctalk]

> On Wed, Aug 11, 2021 at 8:57 AM Fritz Mueller via cctalk
> Could anybody spare a clue or some suggestions on how to access the contents 
> of:
> http://bitsavers.trailing-edge.com/bits/DEC/pdp11/floppyimages/rx02/BASIC-11_V2.1_RX02.DSK.zip

> On Aug 11, 2021, at 1:12 PM, Glen Slick via cctalk  
> wrote:
> 
> Hmm, maybe that BASIC.DSK image file was created by something that
> only copied the initial allocated logical sectors and ignored unused
> logical sectors at the end of the floppy, and maybe PUTR doesn't
> handle disk image files that are not the expected full size?
> 
> Example of padding the 486,400 byte BASIC.DSK image file to a size of
> 512,512 bytes...[which works]

Ah ha!  Thanks much, Glen!

simh is usually pretty good about padding out attached images, but maybe I'll 
try the same thing there and see if RT-11 can then read the disk directly 
itself.  If not, I can extract/rewrite via PUTR.

howto bitsavers BASIC-11 v2 disk image under simh

[Fritz Mueller via cctalk]

Hi folks,

Could anybody spare a clue or some suggestions on how to access the contents of:

http://bitsavers.trailing-edge.com/bits/DEC/pdp11/floppyimages/rx02/BASIC-11_V2.1_RX02.DSK.zip

under simh?  I haven't had any luck mounting the contained BASIC.DSK e.g. on 
simh RY under RT-11.  Looking through a dump of the image, there seems to be an 
"RT11A" signature.  Tried putr under dosbox as well, but it seems to hang 
mounting the image.

Suggestions appreciated!

  --FritzM.

Re: DEC weights

[Fritz Mueller via cctalk]

> On May 23, 2021, at 9:14 PM, Marc Howard via cctech  
> wrote:
> In my case I'm looking for the weight of an RK05 and full height 19" DEC
> rack.

I have not see these published, but can attest that it is somewhere between 1 
25-yr-old-can-load-in-station-wagon and 1 53-yr-old-can-load-in-station-wagon...

Re: QBUS/UNIBUS card handles

[Fritz Mueller via cctalk]

> On May 10, 2021, at 7:14 AM, Joshua Rice via cctalk  
> wrote:
> I would assume it would be trivial to do an injection-moulded run of these 
> handles...

They might also be ideal for silicone mold / resin cast, for smaller/home 
production runs?

Re: QBUS/UNIBUS card handles

[Fritz Mueller via cctalk]

> On May 9, 2021, at 11:18 PM, Dennis Boone via cctalk  
> wrote:
> Does anyone have a design for printing card handles for QBUS / UNIBUS
> cards?  It seems a natural application.

There is an stl file on this page (4th down on the right):

https://so-much-stuff.com/pdp8/cad/3d.php

I had a few of these printed for a Unibone I put together, and they came out 
well.

   cheers,
 --FritzM.

Re: In search of RK05 rack caddy

[Fritz Mueller via cctalk]

> On May 8, 2021, at 8:19 PM, ste...@malikoff.com wrote:
> The rack for 14 RK05 cartridges was the DEC p/n H980-CC Disk Storage Rack, 
> catalog# A-H980-CC.
> ... There were a number of other shelf and rack options ...

Thanks, Steve!  I hadn't heard of the H980-* before.  It looks like an entirely 
dedicated rack media storage system?

The unit I am seeking is smaller, holding just five RK05 cartridges, and is 
commonly seen sharing H960 racks with system units and peripherals.

cheers,
  --FritzM.

In search of RK05 rack caddy

[Fritz Mueller via cctalk]

Okay, now that my 11/45 is up and running well, I could really make good use of 
one of those rack caddiesfor RK05 packs to hold my most commonly used 
system packs for different operating systems.  Anybody have one they'd be 
willing to sell/trade, or at least the DEC part number so I could try to track 
down some drawings?

Looking at pictures on the web, there seem to have been at least two styles: 
one with plated rod wings, and one with sheet metal wings?  I'm supposing I'll 
end up needing to fab something myself unless these are less rare out there 
than I think they are (I've yet to see one go by on ePay, for example.)

cheers,
  --FritzM.

Re: IBM 1410 FPGA Implementation Update - new github repository

[Fritz Mueller via cctalk]

Wow, what a project -- super cool, Jay!

Re: DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

> On May 2, 2021, at 1:25 PM, Josh Dersch  wrote:
> 
> Sorry for the delay, but finally, here's a pile of pictures of the +5V ECO on 
> the backplane.  Let me know if you need more detail on something:
> 
> https://1drv.ms/u/s!Aqb36sqnCIfMpMAqf_6YvmsEEU-T0A?e=Y6WBfV

Oh, this is great, thanks!  It's very interesting to see how this was 
implemented.

I think I will need empty my backplane soon in order to do some lower fan 
maintenance, so I will probably  pull my backplane and implement this at that 
time.

Re: DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

> http://bitsavers.org/pdf/dec/pdp11/1145/KB11-A_revS_Engineering_Drawings_Dec1973.pdf

Thanks very much, Al!

Re: DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

> On Apr 28, 2021, at 9:51 AM, Al Kossow via cctalk  
> wrote:
> 
> I have other 45/70 drawings that i haven't pdf'ed
> I need to see if they are different revs than what I already have

Ohh...  I'd be very, *very* interested to see versions of the /45 drawings 
other than the two sets that are commonly available!

I've been collecting/compiling detailed information about ECOs and board revs 
for the KB11-A (for example, the one that launched this thread!), and looking 
at diffs between the two available drawing sets has been a valuable technique 
for shaking out hints and clues about things otherwise undocumented.  Having 
more to draw from here would be *super* helpful.

A fairly complete summary of things puzzled out so far, for those of you with 
/45s who may be interested, is here: https://fritzm.github.io/ecos.html

cheers,
  --FritzM.

Re: DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

> On Apr 28, 2021, at 9:14 AM, Noel Chiappa via cctalk  
> wrote:
> 
> ISTR a previous, un-fulfilled request for the -11/70 wirelist, so it's been
> missing for a while.
> 
> We _might_ have the -11/45 wirelist:
> 
>  
> http://www.bitsavers.org/pdf/dec/pdp11/1145/1145_System_Engineering_Drawings_Jun74.pdf
> 
> but it's short (pp. 128-132), so maybe it's not complete)? Two other
> print sets seem to have the same list:
> 
>  
> http://www.bitsavers.org/pdf/dec/pdp11/1145/1145_System_Engineering_Drawings_Jun76.pdf
>  http://www.bitsavers.org/pdf/dec/pdp11/1155/MP00039_1155vol1_Mar76.pdf
> 
> (pp. 45-49 and pp 131-135 respectively).

I've been looking for 11/45 backplane wire lists for many years, but have never 
found them.

(Noel: the wire lists in the bitsavers 11/45 drawing sets are actually for the 
power harness, and not for the backplane.)

Re: DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

> On Apr 24, 2021, at 7:02 PM, Josh Dersch  wrote:
> If you have notes on re-creating the harness, let me know.

Hi Josh,

A few pointers -- I think I left some of these in a comment on one of your fb 
posts, but will repeat here in case others may find it useful:

* The wire list in the commonly available Jun74 11/45 engineering drawing set 
is actually for the power harness, and not for the backplane.  It includes wire 
run lengths in inches, which is quite handy.  I believe it is for the newer 
harness, but there is much overlap.

* The old and new harnesses are also schematically illustrated on four pages of 
the drawing set marked "power systems configuration".  These drawings are 
complete and quite good.

* Drawings for the power distribution board for the older wiring style 
(vertical at the back of the cabinet) are hidden in the Jun74 11/*40* 
engineering drawings (upper right of sheet BA11-F0).

* What I did was use the wire list lengths as a guide, cutting each run to 
length plus a little extra.  I then started with the H742s on the bench, at the 
regulator and power monitor mate-n-loks.  Then put the H742s in the rack with 
the CPU cabinet, and worked my up and over the and then down along the along 
the backplane toward the console, bundling and trimming to length as I went.

* A good ratchet lock crimp tool makes a big difference here.  You want one 
with a die that can handle 14 AWG, and on which will crimp both the electrical 
and strain-relief parts of the pins in one go.

* Sticking with the original wire color code also makes it a lot easier not to 
get lost and later to double check and troubleshoot your work.  I used MTW 
("Machine Tool Wire"), which is available from wirebarn.com at 14 and 18 AWG in 
most of the necessary colors and in 25 and 100 foot lengths (I think the 18 AWG 
purple I had to find separately on eBay, but I have lots of leftover of that 
and will gladly send you some.)

* I skipped wiring for most of the regulators in the bottom H742 (I have 
regulator F there, but none of H, J, K, or L are populated) because I don't 
have any core or fastbus memory in my system.  I figure I can add this later if 
I ever do find myself with either of these.

Good luck!

  --FritzM.

Re: DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

Very interesting -- thanks for the info, folks!  My backplane has none of this 
wiring.

I'd really like to see if the traces also look the same, too, though there is 
no real rush.  Hopefully it will be more convenient for Josh to get some 
straight-on pictures, since his backplane is already pulled.

There is also this ECO:

> KB11A-B0008 CODE: DF DD: E WL: E SEP-72 [FCO]
> 
> Problem: Small peripheral controller slots in KB11-A panel, slots 26 thru 28, 
> are not wired to accept some quad module controllers: NPG, PA, PB, LTC, ACLO, 
> DCLO and +15V are missing. Correction: Revise wiring to include signals 
> listed above.

...which I have previously verified is *not* implemented on my backplane.  I 
first noticed this because a DL11 in slots SPC slots 26-28 malfunctioned with 
incorrect signaling levels (because no +15V), but worked just fine if moved 
over to a backplane expansion.  

The fact that my backplane is not wired to support trap to 114 on parity err 
(machine halts instead) has been previously discussed here.  Serial number 152 
on this one -- seems an early bird indeed.

DEC PDP-11/45 backplane +5 ECO

[Fritz Mueller via cctalk]

Hi Josh,

Among the pictures linked from your message about the H742a parts, there is one 
picture of you backplane.   I have been looking for some time for information 
about the following 11/45 ECO:

> KB11-1 CODE: D May-72 [ECO]
> 
> Problem: Etch carrying +5V current from Mate-n-Lock pins to backpanel pins is 
> not heavy enough to carry required current. Correction: Run 24AWG wire in 
> parallel with etch on panels which already have Mat-n-Lock assembly 
> installed. Increase thickness of conductor with solder bead if Mate-n-Lock 
> assembly not installed. PDP-11/45 system serial number 101 and later.

The wiring arrangements at the top of your backplane look to be a bit different 
from mine, and I believe you may have this ECO implemented.  While you have 
your backplane out, could I ask that you take some closeups around the 
Mate-n-Locks along the top?  I'd be very interested to see the board traces and 
the details of the red bus wiring there.

Pictures of the toasted 11/45 suggest that the original machine had the older 
power wiring scheme (distribution panel mounted vertically on back of cabinet 
instead of horizontally at top of cabinet, etc.) although your KB11A serial 
number badge is >2000, which is curious...

Re: DEC H742a Power Supplies, for Parts (Seattle)

[Fritz Mueller via cctalk]

> On Apr 24, 2021, at 11:50 AM, Josh Dersch via cctalk  
> wrote:
> There were two H742a supplies in the rack... I hate to see things go to 
> waste...
> ...the power supply boards look like they might be usable after a good
> cleaning and testing.

Hi Josh,

I have H742a's running in my '11/45, so I'd be happy to give the controller 
boards a good home in my spares cache if nobody else speaks up with a more 
immediate need for them.

   cheers,
 --FritzM.

Re: DEC BA11-K KY11-L mounting brackets -- how?

[Fritz Mueller via cctalk]

> Now that I've thought about it for a bit, I wonder if you can use a
> nut-and-washer in place of the press fit threaded bushing at the bottom (but
> otherwise all the hardware,and insertion directions, will be the same); it
> will be kind of difficult to get the nut in there with the KY11-L pressed up
> to the front of the BA11-K (which is probably why they went to the press fit
> threaded bushing) - maybe hold it with a pair of needle-nose?

Yeah, two solutions come to mind -- the one you mention here with nut and 
washer, or inserting a hex-head machine screw in the other direction.  Either 
the nut or the hex-head screw could then be secured with a small combination 
wrench.

Re: DEC BA11-K KY11-L mounting brackets -- how?

[Fritz Mueller via cctalk]

Thanks for the info, Noel.

There seem to be several small oddities with this cabinet (there was also a 
puzzle I posted about here a while back, related to securing the power monitor 
board; it turned out with that one that this cabinet is missing some internal 
mounting tabs that other folks' cabinets seem to have.)

> On Apr 20, 2021, at 4:14 PM, Noel Chiappa  wrote:
> 
>> Pictures of my brackets should be viewable at
>> https://photos.app.goo.gl/wni3mDAQHozK9Ho27
> 
> I couldn't get them to display on my modern Window laptop, using either the
> Edge or Explorer browsers. I had to get my wife to show them to me on her
> Apple laptop. Not a great site to use for photos.

Wow, sorry about that...  Do folks here have an alternative service they 
like/recommend for sharing linked photos to the list?

cheers,
  --FritzM.

Re: RSX11D disks on EBAY- anyone interested?

[Fritz Mueller via cctalk]

> On Apr 19, 2021, at 8:37 AM, Lee Gleason via cctalk  
> wrote:
> Does anyone have an actual, physical, assembled, currently working  RK05 
> drive that could read it in for me?

Hi Lee -- I have a currently working RK05 attached to an (also currently 
working) 11/45, and would be willing to give this a go for you?  I am in the SF 
Bay Area (Oakland) -- DM me to coordinate details is you wish?

   cheers,
 --FritzM.

Re: DEC BA11-K KY11-L mounting brackets -- how?

[Fritz Mueller via cctalk]

Thanks Paul, Henk!  Yup, it sure looks like there was more than one design for 
this...

Re: DEC BA11-K KY11-L mounting brackets -- how?

[Fritz Mueller via cctalk]

> On Apr 18, 2021, at 7:40 PM, Noel Chiappa  wrote:
> There's an intermediate 10" or so high adapter piece (one either side, of 
> course) mounted to the KY11-L... on the bottom, a single 1" or so machine 
> screw (#8, I think) goes through the vertical tab on the side at the front of 
> the BA11, to a tapped hole in the adapter piece.

Thanks for the details, Noel!

Pictures of my brackets should be viewable at 
https://photos.app.goo.gl/wni3mDAQHozK9Ho27

The interesting/confusing bit for me is the bottom part...  In the second 
picture you can see that my brackets just have a punched oval hole at the 
bottom, and not a "tapped hole" per your description above.  The tabs on the 
chassis to which these brackets mount all have #10 press fit threaded bushings.

The bit at the top, with the plastic pieces (called out on the parts lists as 
"latch, molding") and countersunk #10 screws is clear, and looks like what you 
describe.

> I'll take a look. I'm too burned out (COVID long haul) at the moment to take
> pictures or do a drawing right at the moment; if needed, I can do it tomorrow
> (or so).

Something a lot of us are going to have to face in the upcoming months/years, 
it seems -- wishing you best!

> PS: A while back you were after measurements on the KY11-L power knob;
> did you ever get those: If not, I've got one, and can measure it.

I did not get exact measurements, however, I did find this part:

https://www.millsupply.com/knob-fan-speed-grumman-olson-53777.php?p=324629

...which turns out to be a very suitable replacement: bezel diameter and post 
height are just right, marking lines up nicely with the panel, good feel and 
very sturdy.

cheers,
  --FritzM.

Re: DEC BA11-K KY11-L mounting brackets -- how?

[Fritz Mueller via cctalk]

> On Apr 18, 2021, at 4:57 PM, Mark J. Blair via cctalk  
> wrote:
> I'm not at home with the machine now, but if I remember (or get reminded in 
> the next day or three), I'll try to take some pictures of my PDP-11/34A to 
> help you out.

Thanks, Mark.  I'll get some pictures of the brackets I have, too -- maybe they 
aren't the standard/correct ones for an 11/34...

DEC BA11-K KY11-L mounting brackets -- how?

[Fritz Mueller via cctalk]

Hi all,

I'm reassembling an PDP-11/34 in a BA11-K chassis right now, and am a little 
puzzled by the front mounting brackets (the ones that hold a KY11-L of either 
sort on the bottom, and a half trim-panel on the top).  In particular, on the 
bottom half, the available place for screws to go to attach the bracket to the 
chassis is nearly completely blinded by an overhanging tab.

The engineering drawings I've seen are unfortunately not very clear on this...  
Anybody have an 11/34 in a BA11-K and care to take a peek and tell me how the 
hardware here is properly configured? (Hex head instead of DEC's ubiquitous 
Phillips truss, to allow tightening from the side?  Machine screw from back, 
and a nut on the front?  Other?)

cheers,
  --FritzM.


   

seeking docs for Monlithic Systems 303-0158 unibus memory

[Fritz Mueller via cctalk]

Subject line says it all -- I'm working on a restoration that includes one of 
these, and it looks as if it needs some troubleshooting/repair.  I didn't see 
docs posted at Bitsavers.  Anybody have a manual squirreled away?

cheers,
  --FritzM.

Re: DEC pin

[Fritz Mueller via cctalk]

> On Mar 24, 2021, at 2:39 PM, Kyle Owen via cctalk  
> wrote:
> Does anyone have a picture of the "I've been VAXinated" pin? I know I've
> seen this pin before, probably at some VCF event.

https://www.computerhistory.org/collections/catalog/102682110

Timely!

  --FritzM.

Re: PDP-11/70 progress (and a cry for help)

[Fritz Mueller via cctalk]

> On Tue, Feb 16, 2021 at 2:36 AM Fritz Mueller via cctalk 
>  wrote:
> So you could set up on t4 or t5 of that microinstruction with the KM11...

> On Feb 16, 2021, at 11:08 AM, Josh Dersch  wrote:
> I can't, though -- all of this stuff works fine when running slowly :)

Oh right -- I keep forgetting that part!  So that really does leave you with 
just the LA to catch things in the act I guess.

> Right now I'm thinking it is most likely the AMX selecting the wrong input 
> (I'm guessing that BMX is correctly selecting KOMX, to get the constant "2" 
> for the add operation).

I agree; seems a good place to look next.

> Have the 11/70 microcode PROMs been dumped?  I had to recreate the 11/05 PROM 
> from the listings in the engineering drawings...

I am not sure?  For the 11/45, I also keyed it in by hand from the engineering 
drawings, but since it is only a 32x8 bit ROM this was pretty easy.

   --FritzM.

Re: PDP-11/70 progress (and a cry for help)

[Fritz Mueller via cctalk]

> On Feb 16, 2021, at 1:13 AM, Josh Dersch  wrote:
> My money's on t5 going wrong -- an ALU input mux or operation being selected 
> incorrectly, possibly.  This also somewhat explains why execution doesn't 
> trap due to executing a HALT from an odd address -- it isn't actually 
> executing from the wrong address, because the bus address is loaded from a 
> still-good PCB in t1.

Yes -- that seems to match the observations.  So you could set up on t4 or t5 
of that microinstruction with the KM11 in single-clock-phase mode, and then 
have at the ALU with a logic probe to check...

There is a small ALU control ROM on the GRA (E74 in the upper left of sheet 
GRAA), which selects the ALU mode and operation based on lines coming over from 
the IRC.  I had a failure of this part on my 11/45, and ended up with incorrect 
ALU setup in some circumstances.  That part is a 256-bit DM8598 tri-state 
bipolar mask ROM, and the truth table is on sheet GRAK.

Looking back at my notes, I think it was Glen who informed me (on this list, in 
2016!) that the Signetics 82S123 PROM could be substituted here.  Programmed 
one up, and it worked, in case you run into the same thing and it is useful 
info.

cheers,
  --FritzM.

Re: PDP-11/70 progress (and a cry for help)

[Fritz Mueller via cctalk]

Hi Josh,

In the situation you describe, I guess I would first chip clip '174s for a 
slice of both PCA and PBC on the LA, run the troublesome instruction sequence, 
and look at the trace.  Check that CLKPCA H and CLKPCB H are happening when and 
only when expected, and that all the timing there looks okay.

You would also be able to see good-data-clocked-in-but-bad-data-presented on 
that trace, indicating more failed '174, or see any bad data arriving from the 
ALU upstream.

I'll take a look through the flows after dinner.  The "0002" might be one 
operand used to increment the PC, but the other operand shows up as all zeros 
because of a bad ALU setup?  I guess I'd trace to definitively rule out PCA and 
PCB first, and then move backward around the chain from there verifying the 
ALU, ALU muxs, mux sources, etc.?

--FritzM.

Re: DEC RK11-C Disk Controller - on ebay...or is it?

[Fritz Mueller via cctalk]

> On Feb 9, 2021, at 5:24 PM, Noel Chiappa via cctalk  
> wrote:
> BTW, your neat hack to do that only works on the RK11-C, and not the RK11-D:
> the latter doesn't implement 'Read/Write-All'.

Yup -- this is one of the lesser-known advantages of the RK11-C over the later 
controllers.  Another being the theoretical ability to hook up a blinkenlights 
panel to slots 31 and 32 rows A and B :-)

Also missing from that eBay listing, BTW: the usually accompanying H720-E to 
power the thing.  I wonder if that will be or has been listed separately?

--FritzM.

Re: DEC RK11-C Disk Controller - on ebay...or is it?

[Fritz Mueller via cctalk]

> On Feb 9, 2021, at 9:27 AM, Noel Chiappa via cctalk  
> wrote:
> ... the Unix V6 RK pack formatter ...
> sets _both_ 'Format' and 'Read/Write-All', and _doesn't_ set up the sector
> header words in the memory buffer, arguing that even with 'Read/Write-All' on,
> the hardware is still generating the sector header word contents.

That's quite interesting!

I have experimented with Read/Write-All, but just for reads.  Basically, you 
set up the read and after the index pulse you get the bitstream from one 
surface of an entire cylinder in memory, repeating, inter-sector gaps, sync 
bits, header bits, etc, until the word counter expires.  Bit alignment of the 
stream wrt. memory buffer is in effect arbitrary.

To use the resulting data, you have to detect the sync bits, align the data, 
parse off the sector headers, etc.  In at least one case of attempting to 
recover a pack, I had some sectors that would consistently return read errors 
and no data; by reading entire cylinders in "all" mode and fiddling with the 
data alignment I was in fact able to recover the greater portion of the data in 
some otherwise inaccessible sectors.

  --FritzM.

Re: DEC RK11-C Disk Controller - on ebay...or is it?

[Fritz Mueller via cctalk]

Yup, RK11-C, and it seems complete (modulo drive cables and terminators.)  I 
have one debugged and running in my '11/45, so I know it well.

> On Feb 8, 2021, at 3:16 PM, Ethan Dicks via cctalk  
> wrote:
> The ribbon cables are a bit out of place... perhaps they were just
> stuffed into empty slots to keep them from being damaged.

The cables are actually in the correct slots -- they connect A30 and B30 to the 
pass-through connectors to support plugging in a pair of KM11s from the outside 
of the rack for debug.

On nice thing about this controller is that it supports "Read/Write All" mode, 
which lets you read or write the raw bitstream including block headers.  This 
can be useful for disk recovery if you have a corrupted block header, or for 
reading/writing "foreign" disks (within limits).  This is controlled by bit 9 
in the CSR, which is unimplemented on the later controllers.

--FritzM.

Re: PDP-11/70 debugging advice

[Fritz Mueller via cctalk]

> On Feb 4, 2021, at 9:45 PM, Josh Dersch  wrote:
> The 11/70 is now somewhat operable.  I can examine and deposit memory, at 
> least for a short while -- after the system warms up for 30 seconds or so the 
> Load Address switch stops functioning.

Nice!!  

One handy test on '45 is to put the data display knob to bus address; if the 
microcode is still running in the control panel idle loop (halt switch down or 
fault) the data lights will follow along with the toggles.  This is a super 
quick way to tell if the microcode is still running or if it is wedged.

(The '45 and '70 microcode seem quite similar, so your '70 might have the same 
feature?  I haven't looked at the flow diagrams yet to know for sure.)

   --FritzM.

Re: PDP-11/70 debugging advice

[Fritz Mueller via cctalk]

> On Feb 4, 2021, at 1:51 PM, Josh Dersch  wrote:
> [RC maintenance clock] Yeah, you'd think... but it doesn't work :).  I 
> mentioned earlier in this thread that it's stuck in single-step mode.  From 
> the schematics it looks like the crystal clock needs to be running to clock 
> some of the flip flops used in the "Source Synchronizer" to select the proper 
> clock source.  My guess is that since the clock isn't running, the flip flops 
> are left in a weird state.

Oh, interesting!  Noted for future reference.  The TIG is not exactly 
straightforward...

Re: PDP-11/70 debugging advice

[Fritz Mueller via cctalk]

> On Feb 3, 2021, at 8:07 PM, Josh Dersch  wrote:
> Sure enough, TIGB XTAL H was a flat line.  Nothing happening at the crystal 
> itself either.  The crystal's casing was fairly corroded (which is 
> interesting, since nothing else on the board is) and after a tiny bit of 
> prodding one of the legs fell off, so I'm hoping that's the culprit.

Ah.  One of the switches on the KM11 should enable the machine to run off the 
separate RC maintenance clock on the TIG, if you want to keep going before your 
new crystal shows up.

Re: PDP-11/70 debugging advice

[Fritz Mueller via cctalk]

> On Jan 31, 2021, at 8:19 PM, Josh Dersch  wrote:
> Well, what's interesting here is that on my system, switch S4 (MAINT STPR) 
> steps the processor with switches S1 and S2 set to *any* configuration.

Hmm, would expect to see S2:1 S1:0 step by microinstruction, and S2:1 S1:1 step 
by clock phase.  The other two settings should free run the microcode.  So 
yeah, sounds like something fishy there...  The TIG card has more than a few 
analog components, and its not too unusual for these to get hung up on the 
adjacent card and have a leg pulled or sheared from the board.

> Ah, and page II-6-20 (p. 178) indicates that when DCLO is asserted, it 
> asserts: "UBCE ROM INIT H - forces the ROM to ZAP.00 (200), and stops and 
> clears the Timing Generator and the Cache timing."

Yup, that's one of the signals coming in to RAC E106.  Probing there should 
indicate which of possible sources for ZAP is actually occurring (UBCE ROM INIT 
H on pins 2 and 3 there).

DCLO is a classic...  Make sure to 'scope it, because it sometimes has 
troublesome spikes that don't show on a multimeter.  If you have H742s, there 
are some wet tantalums on the control board that sometimes leak and cause 
trouble with this.

I'm sure you are raring to go -- hope those fans show up for you tomorrow, and 
will be interested to hear what you find!

  --FritzM.

Re: PDP-11/70 debugging advice

[Fritz Mueller via cctalk]

> Yeah.  I want to get the fans installed and then go triple-check all the 
> power signals and get the voltages dialed in nicely.  But then things come 
> out on extenders :).

Yup -- I'm surprised how picky my '45 is about +5 undervolt; it really seems 
happiest with trimmed up to about 5.1 at the backplane.

Looks like E106 on the RAC (M8123) might be a good place to start (drawing 
RACA, lower left.)

cheers,
  --FritzM.

Re: PDP-11/70 debugging advice

[Fritz Mueller via cctalk]

Hi Josh,

ZAP is effectively reset for the micro-architecture, forcing the ucode address 
to known/initial value.  It has multiple sources throughout the processor, 
including tendrils into some of trap handling hardware. (Caveat: my experience 
is based off extensive work with the '11/45, but the micro-architecture as I 
understand it for the '11/70 is quite similar.)

For the '45, there was a very handy "KB11-A,D Maintenance Manual", which 
explained the logic of such internal signals and the board by board internal 
operation of the CPU to a very useful level of detail; I'm sure similar is 
available for the KB11-B,C?  It's worth a read through if you haven't already, 
though its quite a bit to take in.

I would imagine the next step would be to throw the RAC board out on extenders, 
verify that ZAP is asserted, and if so pursue the driving source.

Do you know if you have a KB11-B or C?

Happy hunting!

   --FritzM.

Re: DEC backplane power connectors

[Fritz Mueller via cctalk]

>>>  There is definitely yet _another_ keying design, with
>>> triangular sawteeth
> 
> Molex

Yup. You'll find them on harnesses in your Atari arcade cabinets :-)

Re: DEC backplane power connectors

[Fritz Mueller via cctalk]

> https://gunkies.org/wiki/DEC_power_distribution_connectors#Connectors

Very useful page; thanks Noel!

> I'm not sure why I bothered to write all this stuff up; it was clearly a waste
> of time.

Arguably (?) not, if you consider cctalk to be the "search engine" that links 
people there :-)

   --FritzM.

Re: securing 15V pwr monitor board in H765 supply

[Fritz Mueller via cctalk]

> On Jan 19, 2021, at 3:11 AM, Paul Birkel  wrote:
> Fritz:  You are referring to the 5411086 board as seen in the lower picture 
> at: http://gunkies.org/wiki/DEC_Power_Line_Monitor ?

Yes, exactly.

> Mine has screws on all four corners to secure it to corresponding tabs in the 
> metal frame for the power control circuitry.

Interesting -- there are no such tabs in metal frame that I have; just a slot 
into which to board slides.

Thanks for taking the time to check, Paul -- I think I might just end up 
drilling some holes and adding a couple bolts to secure board in the frame I 
have.

--FritzM.

DEC: securing 15V pwr monitor board in H765 supply

[Fritz Mueller via cctalk]

Hi all,

I’m reassembling an H765 supply after cleaning and repairs.  It has the "newer" 
style 15V and power monitoring board (the one with the edge finger connector, 
same as used in H7420 supplies.)

The board slides into a slot in a sub-chassis that also houses the power 
control circuitry, which small chassis later slides into, and is secured to, 
the larger H7420 chassis.

I cannot for the life of me figure out what, if anything, secures the power 
monitor board to the small chassis! There don’t appear to be any conveniently 
placed fixtures to which to screw down the board, and I haven’t been able to 
inform myself by pondering the various engineering diagrams, IPB’s, nor the 
pile of remaining fastening hardware...

When I test-fit everything in the larger chassis, the unsecured board is held 
captive only by the grace of the surrounding wiring harness and by some small 
clearance issues with the large cap on the board.  This doesn't seem 
satisfactory; as part of something like an 11/34 on tilt slides, it would seem 
to bang around a bit in there if left loose like that.

Am I missing something?  Puzzled...

 --FritzM.

Re: PDP-11/34 /04 power knob anyone?

[Fritz Mueller via cctalk]

This might be a reasonable stand-in for now:

https://www.millsupply.com/knob-fan-speed-grumman-olson-53777.php?p=324629

> On Jan 9, 2021, at 4:25 PM, Fritz Mueller  wrote:
> 
> 
>> On Jan 9, 2021, at 3:54 PM, Bill Degnan  wrote:
>> 3d-printable?
> 
> It would seem so.  I don’t have one to measure, though, and I haven’t seen 
> any 3d models online yet.  I could probably eyeball it, but anybody have one 
> and care to measure?
> 
> Does the original have a brass bushing?
> 
> 

Re: PDP-11/34 /04 power knob anyone?

[Fritz Mueller via cctalk]

> On Jan 9, 2021, at 3:54 PM, Bill Degnan  wrote:
> 3d-printable?

It would seem so.  I don’t have one to measure, though, and I haven’t seen any 
3d models online yet.  I could probably eyeball it, but anybody have one and 
care to measure?

Does the original have a brass bushing?

PDP-11/34 /04 power knob anyone?

[Fritz Mueller via cctalk]

Hi folks,

I’m working on an 11/34 at the moment, with the programmer’s console, and it is 
missing its front panel power control knob.  I think it is the same one used on 
the 11/04?  Anybody have a spare in their parts stock that they’d be willing to 
part with?

(I’m also missing the plastic half-panel for the front, but I do see those go 
by on eBay from time to time.)

cheers,
  —FritzM.

DEC H765 line interference caps

[Fritz Mueller via cctalk]

Hi all,

I’m just starting in on a PDP-11/34 for a friend (happy holidays!)  I currently 
have the H765 power supply torn down for cleaning, inspection, and testing as a 
first step.

While I have the transformer out on the bench, I’m wondering about the line 
interference supression caps on the “CAP MOV” board attached to the 
transformer.  These are CDE 220 VAC .1 MFD, across the line, in parallel with 
some metal oxide varistors.

Drawing on collective experience here: would I be well advised to go ahead and 
swap these out for some modern X2 safety caps while I have the supply apart?  
Or are these in the “oh those are rock solid; I wouldn’t touch em unless they 
were faulted” category?

cheers!
  —FritzM.

Re: Fire-Sale PDP-11 update (and request for parts)

[Fritz Mueller via cctalk]

> On Dec 4, 2020, at 10:41 PM, Josh Dersch via cctalk  
> wrote:
> I realize this is unlikely, but I was curious if anyone has 1) any
> parts of the 11/45 power wiring harness...  I can build my own wiring 
> harness, but if I can save
> myself the trouble, that'd be nice.

Yeah, I had build my own for my /45 restoration.  It wasn't all that bad.  
Throw down for a nice ratcheting single-gesture crimp tool for the job and 
you'll be glad that you did :-)

I found wirebarn.com had a nice selection of wire available in 
less-than-full-spool lengths, and most of the original colors.  I may have had 
to fill in a few things from other suppliers (I found it helpful to stick to 
the original color coding.)

Another tip is that the wire list you see in most of the /45 drawing sets is 
actually for the power harness, and not the backplane.  The wire lengths in 
that list were useful; I cut to those lengths, then started on the regulator 
side of the harness, installed in the machine, and bundled and trimmed to 
length as I worked my way down the backplane.  In the end I had a reasonably 
neat fit and very little wasted wire.

I had the extra wrinkle of having the earlier (serial # <2000) power 
distribution system in my /45 (IIRC the wire list was from the newer system, 
but it wasn't too hard to adapt it.)

Do you have the springy steel strip that supports the harness between the 
moving and stationary parts of the cabinet?  That may require some fab or 
improvisation if not.  I had one left over from an 11/40 that I was able to 
make work well enough with my older style cabinet.

   cheers,
 --FritzM.

Re: RK11-D "diskless" test ZRKJE0???

[Fritz Mueller via cctalk]

> On Jul 9, 2020, at 5:02 PM, Robert Armstrong via cctech 
>  wrote:
> I have an 11/04 with an RK11-D.  I have a couple of RK05s, but I wanted to 
> test the controller before I start working on the drives.  The PDP11 
> Diagnostic Handbook says that ZRKJ?? "checks only the drive-independent logic 
> of the RK11 controller. no drive is needed..."  I assumed that meant it was a 
> diskless test, but now I'm not sure that's true.  Can anyone confirm or deny 
> this?

Hi Robert,

My experience with an RK11-C on a PDP-11/45 is that the drive-independent 
diagnostic does in fact work with no drives attached. For the RK11-C at least, 
it does clever things with maintenance-mode to simulate signaling that would 
source from the drive where necessary.

I know there are some differences between the RK11-C and the RK11-D -- if some 
of these are related to maintenance mode, it could also be that you need to 
verify that the version of the diagnostic you are running is RK11-D (and not 
just RK11-C) aware?

Another possibility is that you should pull the BC11 and add another terminator 
rather than leaving it dangling?

--FritzM.

Re: Who changed the gravitational constant (Dec pdp11 stuff)

[Fritz Mueller via cctalk]

On 11/22/19 11:16 AM, Chris Zach via cctalk wrote:

https://i.imgur.com/7BwIwas.jpg


Ah man, I'm jealous of your VT52 roll-around stand -- wish I could find 
one for my VT52!


   --FritzM.

Re: RX01 wants

[Fritz Mueller via cctalk]

Hi Ethan,

> On Nov 17, 2019, at 11:25 AM, Ethan Dicks  wrote:
> The box is kind of fun, and was standard for word processors and the
> MINC-11 but I can understand wanting a rackable system.

Thanks for the info!

I’m all for keeping things intact when possible, so I’d also be happy to do a 
trade for a rackable RX drive if anybody is interested.  Otherwise, would 
definitely want to pass the box on to any interested collector.

  --FritzM.

Re: RX01 wants

[Fritz Mueller via cctalk]

Hi Ulrich,

> On Nov 17, 2019, at 3:59 AM, Ulrich Tagge via cctalk  
> wrote:
> I'm interested in the RX01 Drive and equipment.
> Where is the stuff located?

Unfortunately, the list in my email was stuff I wish to buy, not sell :-)

Sorry for being unclear!

--FritzM.

Re: RX01 wants

[Fritz Mueller via cctalk]

Hi Paul,

> I think you mean RX11.

Ah, yes — I typo’d that, thanks!

> Isn't the BC05L-15 folded up in the case? Or did they put a short one to the 
> back of the box?  I can't remember now.

I’ll have a look to remind myself when I get downstairs later today.  IIRC, 
everything is brought out to D-shell connectors on the back of the box?

> Which are you on located? I know someone who was looking for a box last year.

I’m in Oakland, CA.  I’d gladly pass the box on to some other collector if I 
can find rails. 

> Are they the old Calcomp cast aluminum, or the newer DEC 70 class drives? The 
> DEC ones 
> can sometimes be converted to RX02s. I think the older (RX01 only) were the 
> M7726 and M7727.

Will check and post back.

   Thanks!
 —FritzM.

RX01 wants

[Fritz Mueller via cctalk]

Hi all,

I recently picked up a “tabletop” RX01 drive for cheaps.  So now I’m in the 
market for:

- RK11 controller
- cables
- rack ears, rails (how was this done?)
- formatted media

If anybody here might have any of this and like to work out a deal, feel free 
to let me know off-list!

   thanks much,
 —FritzM.

Re: Looking for documentation for VAX-11/730 ENKCC Diagnostic

[Fritz Mueller via cctalk]

> On Nov 13, 2019, at 9:21 AM, Jay Jaeger via cctalk  
> wrote:
> Sure.  Works for me.  There are, in all, likely well over 1000 fiche...
> 3)  I have several sets.  Which of them would you want to scan?
> 
> On 11/13/2019 12:02 AM, Josh Dersch wrote:
>> 
>> If you're willing to send them out, the LCM would be happy to scan them
>> and get the scans off to Al, etc.

When I was working through some issues on my 11/45 last year, Jay tracked down 
several DEC-O-LOGs in these fiche that I had not been able to find anywhere 
else.  I would be pretty psyched to see otherwise missing DEC-O-LOGs and 
diagnostic listings scanned!

—FritzM.

Re: UNIBUS FTGH: EMM / CMU MICRORAM memories

[Fritz Mueller via cctalk]

There were only 2 11/45s that I knew of.  The first was the “front end” 
that sat in front of all of the terminals and allowed connection to the 
various 10s (at the time there were 3: 2 KA10s and a KL10), C.MMP and 
CM*.  The other 11/45 ran the XGP...


They had moved on to a Xerox 9700 and DECSYSTEM-20s behind Micom port 
selectors by the time I first rolled up there in 1984.  CS still had a 
cluster of PERQs in Wean Hall.


Not too long after that, the DECSYSTEM-20s were decom'd, and the old 
terminal clusters were converted over to IBM PCs, Macs, and IBM RT 
Andrew workstations.


  --FritzM.

Re: UNIBUS FTGH: EMM / CMU MICRORAM memories

[Fritz Mueller via cctalk]

First off, I've had a couple of follow-ups on these units, so they are 
spoken for at this point.


The member with first dibs has also offered to scan the docs and see 
that they make their way to Al.


I was wondering if these were c.mmp cast-offs?  Guy: I encountered these 
in the CMU computer club hardware room (Doherty Hall basement, I think?) 
circa 1986.  There were a couple of '11/40s adjacent, and those did have 
some sort of custom writable control store cards.


The computer club was cleaning house, so I hauled off an '11/45 with CPU 
spares that looked pretty stock, the aforementioned memory units, and a 
rack mount Tek 'scope (about all I could convince my friends to help me 
haul off campus at the time :-)


Not sure what ever happened to the rest of the equipment that was down 
there.  I know they had a couple of working Altos, on a thick net 
segment with the old vampire transceivers that had the little round 
glass windows in an aluminum box.  And what must have been parts of an 
earlier PDP (I remember a smallish teletype bolted on to a piece of 
white Formica desktop.)


--FritzM.

FTGH: EMM / CMU MICRORAM UNIBUS memories & docs

[Fritz Mueller via cctalk]

Okay, I'm trying to beat back the hoard in my basement before the rainy season 
starts here in CA:

I have a couple of NMOS static RAM UNIBUS address spaces that I picked up from 
CMU sometime back in the mid-'80s once when they were cleaning house.  I've 
been hauling these around for 30+ years, thinking I would use them with the 
'11/45 that I picked up at the same time, but as previously discussed here I 
have a much more practical MS11-L working in that system now.  So, I'd be more 
than happy to pass these one to somebody else who could put them to good use?

There are two; they are 5U 19" rack chassis with integrated power supplies and 
fans.  These are card cages with slots for 5 11"x15" cards plugging, into a PCB 
backplane (big, heavy!)

Each chassis contains four fully-populated MICRORAM 3400N memory cards (at 32K 
words x 18 bits each, each chassis is a full UNIBUS address space); each of the 
memory cards caries 144 x socketed 4402ACC, with 1977 date codes.

Each chassis also has a fifth card, a custom UNIBUS interface card that was 
developed at CMU, which takes the place of the self-test card in the original 
units.

The units are marked S/N 11 and 12, P/N 929331-009A.  They are in good 
shape, but dusty, and with some corrosion evident on the chassis.  Have not 
seen power in several decades, so the power supplies probably need a going 
over...

I also have full documentation (including schematics), and a folder of 
schematics and some hand-drawn notes for the CMU interface cards.  I have dups 
of the EMM documentation, so could send it to Al if he is interested? 

Anybody out there interested?  I am in Oakland, CA.  It would be best to pick 
these up in person, because they'd probably be $$$ to ship.

cheers,
  --FritzM.

Re: multi-section cap for Tek 4006

[Fritz Mueller via cctalk]

> On Aug 18, 2019, at 1:52 PM, Al Kossow via cctalk  
> wrote:
>> Rebuilding cans is a common practice now, since they are LONG out of 
>> production.
> https://www.nmr.mgh.harvard.edu/~reese/electrolytics/

Thanks, Al.  This is definitely plan B, unless somebody here comes through with 
a miracle "oh I have those...", or "there's a pile over at X...", or "they're 
also used in Y so look for one of those."  (Don't know until you ask, 
especially around this crowd :-))

   cheers,
 --FritzM.

multi-section cap for Tek 4006

[Fritz Mueller via cctalk]

I'm working my way through a Tektronix 4006 terminal purchased of eBay right 
now.  First stage is the low voltage power supplies, and I noticed right away 
that one of the multi-stage electrolytic filter caps there was running quite 
hot (this was with downstream electronics isolated, and a 40 ohm dummy load on 
the +20V supply per recommendation in the service manual.)

The cap in question is a multi-section Mallory can, 150@400 / 150@250, used to 
filter the +185 and +320 unregulated supplies.  It is C395 A/B on the 
schematics, Tek part 290-0549-00, Mallory part 68D20193.

This terminal is so beautifully engineered inside that it would be a real shame 
to replace this with some sort of ugly bodge.  Any part-sourcing gurus out 
there able to steer me in a good direction here?  I have found the part listed 
in the various online NSN aerospace cross-referencing sites, but haven't 
bothered to ask for a quote from any -- I'm guessing cynically that "RFQ" + 
"Aero..." = 5 zillion dollars for one piece... :-)  Has anybody here used one 
of these sites successfully?

cheers,
  --FritzM.

Re: XXDP on PDP-11/03

[Fritz Mueller via cctalk]

> I don't know if the front console on the early UNIBUS machines works without
> any memory on the UNIBUS - I'm too lazy to check. I have this vague memory 
> that
> they do, though.

The front console on the '45 indeed does run just fine with no UNIBUS (or 
FASTBUS) memory in the machine.  Its is entirely implemented/mediated by CPU 
microcode and CPU internal state registers.

  --FritzM.

Re: I'm sharing a toy

[Fritz Mueller via cctalk]

> I don't think writing SIMH device emulators for things like the DEC Unibus 
> D/A and A/D devices, or the DR11-A, would be at all hard.

Yes; I have also thought it would be nice to have something like a DR11-C in 
simh, which could be configured to call into a dynamic library containing user 
code to emulate a custom connected device.

   --FritzM.

Re: keycaps / switches for Tek 4006

[Fritz Mueller via cctalk]

After a little more research on the net tonight: it looks like the keyboard in 
the 4006 was pretty much one of Cherry's standard "B70 ASR" models.  The key 
mechs are known as M7 T-mount, and the caps look like the standard double shot 
ones supplied by Cherry in their mid to late 70's catalogs.

A lot of the Tek terminals I've seen for sale seem to be missing a few teeth; I 
guess these caps didn't hold on well enough to weather the decades without a 
few from most keyboards getting lost along the way.  It's probably worth 
working up some 3D models for these caps.

Also, keyboard research turns up some sad, sad, things... B... :-(

--FritzM.

Re: keycaps / switches for Tek 4006

[Fritz Mueller via cctalk]

> Can you take a picture of the switches?
> Cindy

Some pics of they keyboard assembly, key cap underside, key mechs, and also the 
power toggle I'd like to replace, are here:

https://drive.google.com/open?id=1dKBOdhwgpedYpYCKbGxrd3P9jCNwBRs5 

https://drive.google.com/open?id=1U__BCVWJQgP-s0ZrPMBWQ21LWM2jsWjP 

https://drive.google.com/open?id=1hh-SXbyIW_hjeMZnbVZzx56-VRwFBcDM 


https://drive.google.com/open?id=17YNPFk9KUm4mZnjAV3EFCY09JXASNMtI 


thanks,
   --FritzM.

Re: keycaps / switches for Tek 4006

[Fritz Mueller via cctalk]

> On Jul 25, 2019, at 10:29 AM, Fritz Mueller  wrote:
> 
> I recently obtained a Tek 4006 from eBay as a repair/restoration project.  It 
> is missing a few keycaps (both SHIFT keycaps, COPY, LINE FEED, and :/*).  In 
> addition, one of the key mechanisms has a broken plunger.  Last, the little 
> green paddle line power toggle power switch at the back appears to be broken.

After disassembly, I can see the keyboard assembly are marked "Cherry" and part 
number is B76-07AA.  I'm not enough of a keyboard wonk to know if these are 
still-mfg'd cherry key mechanisms?

The keycaps look like glossy dark gray / white double-shot deals...

--FritzM.

keycaps / switches for Tek 4006

[Fritz Mueller via cctalk]

Hi folks,

I recently obtained a Tek 4006 from eBay as a repair/restoration project.  It 
is missing a few keycaps (both SHIFT keycaps, COPY, LINE FEED, and :/*).  In 
addition, one of the key mechanisms has a broken plunger.  Last, the little 
green paddle line power toggle power switch at the back appears to be broken.

Pinging here to see if anybody has spares of these in their collection which 
they'd be willing to part with?  Alternatively, recommendations on compatible 
key mechanisms/caps, or even 3D models to print some temporary replacements 
would be appreciated!

  cheers,
--FritzM.

Re: Kaur Collection Inventory

[Fritz Mueller via cctalk]

Hi Adam,

2307 is an LA30-P (the parallel version of the LA30), like the ones restored by 
Herb, Mattis, and myself:

http://www.retrotechnology.com/herbs_stuff/decwriter.html
http://www.datormuseum.se/computers/digital-equipment-corporation/pdp-11-04 
(scroll down 3/4)
http://fritzm.github.io/la30-4.html

  --FritzM.

Re: PDP-11/40 available, Arizona

[Fritz Mueller via cctalk]

On 5/10/19 6:42 PM, Adam Thornton via cctech wrote:

I have been invited out to the site tomorrow morning to take an inventory of 
what’s there (I live near the machines).
I imagine that I may well have a lot of photos that I bring to the list and say 
“what is this?”


Standing by to help out!  Go get it, Adam -- (come on, you can _make_ 
room! :-))

Re: SIMH question

[Fritz Mueller via cctalk]

> On Apr 23, 2019, at 5:34 PM, Charles via cctalk  wrote:
> 
> This may be a silly question... but how can I transfer a text file from my PC 
> into SIMH for PDP-11?

I've found the most convenient way to do this, for a file or two at a time, is 
to use the paper tape reader/punch devices.  These can be attached directly to 
single files on the SIMH host, then the contents can be copied into or out of a 
simulated OS with PIP, cp, etc.

--FritzM.

atex system in Houston

[Fritz Mueller via cctalk]

Hmmm, are these the atex racks seen lurking in the background of that recent 
storage space trawl down near Houston?

https://www.ebay.com/itm/Vintage-DEC-PDP-11-34-Minicomputer-With-Kennedy-Tape-Drive-J11-CPU-2-Terminals/123688125244

Re: V6 cc needs hash before whitespace before first include?

[Fritz Mueller via cctalk]

> On Feb 28, 2019, at 11:43 AM, Phil Budne  wrote:
> It's an indicator that the pre-processor needs to be run first.

Ah, okay!  So that's a fun bit of V6 apocrypha.  Was this gone by V7?