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KDJ11-B: Troubleshooting console SLU

S

subgeniuskitty

Member
Joined
Aug 5, 2015
Messages
15
Location
Tacoma, WA
Hello all,

I've saved my pennies and purchased a KDJ11-B that supposedly worked when put in storage many years ago. Unfortunately, I can't get any output on the console despite correct responses from the diagnostic LEDs. Before I decide it's a problem in the machine, I wanted to run my configuration by the forum to check for user errors and solicit troubleshooting tips.

The serial console, cables and bulkhead panel were all verified with my KDF11-B immediately before I replaced it with the KDJ11-B. All three jumpers (W10, W20 & W40) on the KDJ11-B are in the default/factory positions as shown in the manual. I do not have the proper bulkhead panel for the KDJ11-B so I have configured the onboard switchpack as follows:

Code: 
Switch State Notes
------ ----- ---------------------------------
    1   off  console enabled
    2    on  go directly to ODT mode [1 of 3]
    3    on  go directly to ODT mode [2 of 3]
    4    on  go directly to ODT mode [3 of 3]
    5    on  do not go directly to dialog mode
    6    on  9600 baud SLU [1 of 3]
    7   off  9600 baud SLU [2 of 3]
    8    on  9600 baud SLU [3 of 3]

I am reusing my KDF11-B bulkhead panel for its DB25 port. Comparison of the KDF11-B manual and the PDP-11/84 technical reference seems to indicate that they use a compatible (although not identical) pinout.

On powerup the diagnostic LEDs, when viewed from the back and read left to right (MSB to LSB), are 111011_2 or 73_8 which, according to the manual, means the CPU is powered up and in ODT. That is as I desire, but I am unable to obtain any output on the console.

If I change switches 1-5 to off, then I should be enabling the console and forcing entry to dialog mode. This also results in zero console output and the diagnostic LEDs read 61_8 indicating a line clock problem. I think that's to be expected since I am using an ATX power supply and leaving the BEVNT L line undriven. My intention is to use the LTC on the KDJ11-B once I am able to access the setup menus.

Also, section 2.2.2.4 of the KDJ11-B manual states that if switch 1 is on, then the console is disabled and "any input from the console results in an error message to inform the user that the console is disabled." However, even with switch 1 on there is no output on the console when I type.

=====

Since the diagnostic LEDs seem to give reasonable results for the different configurations, I'm tentatively assuming that the J11 is good and the problem resides in the SLU circuitry.

QUESTION: Can I disable the onboard SLU and use a DLV11-J as the console? If so, how? I have an untested DLV11-J but I could see if it works with my KDF11-B and then transfer to the KDJ11-B. The impression I get from the KDJ11-B manual is that the console disable switch is intended for security purposes and doesn't actually turn off the SLU circuitry.

QUESTION: Where is pin 1 on the J1 connector of the KDJ11-B? The missing/index pin (#6) seems to indicate that pin 1 is toward the same side of the PCB as the CD backplane connectors. However, there is a "1" in the upper copper layer of the PCB that is located on the other side of the J1 connector (toward the AB side of the board) and suggests that the connector is flipped with respect to the KDF11-B and DLV11-J. I decided to trust the missing/index pin when deciphering pinouts, but maybe that was incorrect.

QUESTION: Can I short the TX and RX lines so that my console receives everything it sends? If so, where in the signal path can I safely do this? As long as I can do it on the CPU board I will be able to verify all my wiring from the serial console to the bulkhead panel and then to the KDJ11-B board.

My next plan is to look up the pinout of the UART IC and use an oscilloscope to see if the signals from my console are arriving, if the UART is trying to send anything in response, and if the UART is receiving any instructions from the CPU.

QUESTION: Does anyone have any better suggestions?

QUESTION: Does anyone have schematics for the KDJ11-B?

=====

In case anyone wants to reference the manuals, most switch settings and pinouts for the KDJ11-B came from section 2 of the User's Guide. The pinout for J1 (the SLU) came from the 11/84 technical reference manual on page E-2. KDF11-B pinouts came from table 13-7 on page 13-5 of the KDF11-B User's Guide.

=====

I'm not particularly experienced with the PDP-11 so any suggestions, no matter how obvious they may seem, are welcome.

Aaron
 
subgeniuskitty said:
My next plan is to look up the pinout of the UART IC and use an oscilloscope to see if the signals from my console are arriving, if the UART is trying to send anything in response, and if the UART is receiving any instructions from the CPU.
Click to expand...

This did the trick. The problem turned out to be a DC319 UART (DLART?) that seems to respond to bus inquiries but fails to send or receive anything over the serial line. I borrowed a replacement from another board and, after discovering the Ctrl-o key sequence to unlock the option to bypass clock errors, was able to boot RT-11 and partially boot BSD.

I guess this means that system tests number 64-66 only test the interface to the UART and not its output, since this system was passing the tests.

subgeniuskitty said:
QUESTION: Where is pin 1 on the J1 connector of the KDJ11-B? The missing/index pin (#6) seems to indicate that pin 1 is toward the same side of the PCB as the CD backplane connectors. However, there is a "1" in the upper copper layer of the PCB that is located on the other side of the J1 connector (toward the AB side of the board) and suggests that the connector is flipped with respect to the KDF11-B and DLV11-J.
Click to expand...

For anyone encountering this in the future, the missing/index pin is pin 6 and the connector has exactly the same orientation as the KDF11-B and DLV11-J. Thus, pin 1 is toward the CD side of the board, not the AB side.

Aaron
 
subgeniuskitty said:
I am reusing my KDF11-B bulkhead panel for its DB25 port. Comparison of the KDF11-B manual and the PDP-11/84 technical reference seems to indicate that they use a compatible (although not identical) pinout.
Click to expand...
Please provide a link to KDJ11-B J1 pinout. My suspicion is that this is the major problem. Do you have an RS-232 line analyzer or an oscilloscope?

Since the diagnostic LEDs seem to give reasonable results for the different configurations, I'm tentatively assuming that the J11 is good and the problem resides in the SLU circuitry.
Click to expand...
Hard to proceed without making the assumption that the CPU is running, etc. I would back up and start with cabling from scratch (either the correct cabinet kit or a homemade cable that plugs in to J1).

QUESTION: Can I disable the onboard SLU and use a DLV11-J as the console?
Click to expand...
No.

QUESTION: Where is pin 1 on the J1 connector of the KDJ11-B? The missing/index pin (#6) seems to indicate that pin 1 is toward the same side of the PCB as the CD backplane connectors. However, there is a "1" in the upper copper layer of the PCB that is located on the other side of the J1 connector (toward the AB side of the board) and suggests that the connector is flipped with respect to the KDF11-B and DLV11-J. I decided to trust the missing/index pin when deciphering pinouts, but maybe that was incorrect.
Click to expand...
Your pinout assumptions about the KDJ11-B and KDF11-B are probably incorrect.

My next plan is to look up the pinout of the UART IC and use an oscilloscope to see if the signals from my console are arriving, if the UART is trying to send anything in response, and if the UART is receiving any instructions from the CPU.
Click to expand...
Not a bad plan, but it would probably be simpler to trace the signals from the UART through the RS-232 line driver and receiver chips to the pins of J1 and hack your own cable.

Another approach might be to make a J1 breakout cable and see which signal lines are being driven to RS-232 mark levels and see if any of them turn out to be the console output line. This might be quicker than anything else if you have a connector and some cable to start with and something to look at the signals with.

In case anyone wants to reference the manuals, most switch settings and pinouts for the KDJ11-B came from section 2 of the User's Guide. The pinout for J1 (the SLU) came from the 11/84 technical reference manual on page E-2. KDF11-B pinouts came from table 13-7 on page 13-5 of the KDF11-B User's Guide.
Click to expand...
I suggest that you provide links when you reference manuals to reduce googling by the people trying to help you. This also ensures we are seeing the same revisions that you are, and could possibly point out an error in your selection (although I doubt there is any error of that type with the boards in question).
 
Last edited:
Thanks for the reply. I solved the problem but my post about it is awaiting approval.

Another approach might be to make a J1 breakout cable and see which signal lines are being driven to RS-232 mark levels and see if any of them turn out to be the console output line. This might be quicker than anything else if you have a connector and some cable to start with and something to look at the signals with.
Click to expand...

That's a good idea. I'll add it to my bag.

I suggest that you provide links when you reference manuals to reduce googling by the people trying to help you. This also ensures we are seeing the same revisions that you are, and could possibly point out an error in your selection (although I doubt there is any error of that type with the boards in question).
Click to expand...

Will do.
 
I have an M8190 KDJ11-B in an 11/84-E chassis. I don't have the proper console bulkhead panel for that. I just built a quick console cable with some 10-pin ribbon cable, a 10-pin IDC connector, and soldered the appropriate wires (GND, RX, TX) to pins on a DB9 connector. I probably also soldered two of the wires together in the usual DEC scheme. I'll have to take a look to check exactly what I did. Simple and works fine.

I also have a couple of BA23 chassis with M8190 KDJ11-B with the proper console bulkhead panels.

If you get really stuck there are a few local people that could help you take a look and maybe try some part swapping if necessary.

What kind of chassis / backplane are you using? If you swapped an M8189 KDF11-B out for the M8190 KDJ11-B I hope you are already aware of all of the C22/CD - PMI bus restrictions when using an M8190 KDJ11-B.
 
KDJ-11B Console Cabinet kit

KDJ-11B Console Cabinet kit

subgeniuskitty said:
Hello all,

I've saved my pennies and purchased a KDJ11-B that supposedly worked when put in storage many years ago. Unfortunately, I can't get any output on the console despite correct responses from the diagnostic LEDs. Before I decide it's a problem in the machine, I wanted to run my configuration by the forum to check for user errors and solicit troubleshooting tips.

QUESTION: Does anyone have any better suggestions?

QUESTION: Does anyone have schematics for the KDJ11-B?

I'm not particularly experienced with the PDP-11 so any suggestions, no matter how obvious they may seem, are welcome.

Aaron
Click to expand...

Aaron,
I have not seen schematics for the KDJ-11B or for the console cabinet kit SLU PC board. However, if you have some pennies left, I think you can buy just the console cab kit from Keyways in Ohio. I bought one from Mitch about a year ago for $75. You get the two ribbon cables and the panel which fits into either a BA23 or BA123. The panel has a two digit LED for diagnostics and the RS232 connector as well as a dial switch to change baud rates. I do have a KDF-11B and console kit also, and although I've not compared them closely I think they are pretty different.

The two digit (octal) LED display can also be written to by user programs at 177524 (when the I/O page is mapped) and I've used it to debug code in interrupt routines when it is not easy to know what's happening. So I found it useful for that capability as well.

Best Regards,
Mark
 
Matlock & gslick,

I'm only installing the KDJ11 in my 11/23+ chassis to test functionality and get the right software loaded on the drives. After that it's going in a homemade case where I do plan to make my own headers, as you suggest.

I didn't know you could write to the LED display. That's neat!

I am aware of the different QBus backplane configurations, including PMI. This backplane is a three slot AB/CD and then AB/AB the rest of the way down. For now I have a single MSV11-P underneath the KDJ11-B followed by a dual-width SCSI controller. I just purchased more RAM to get me to 1 Mb so I can run 2.11BSD, but still non-PMI due to budget, so it will sit in slot three (the last AB/CD slot) and the SCSI card will get bumped down to the first half of slot 4.
 
When I built my 11/83 I made my own cab kit, SLU control diagnostic panel, and serial port bulk heads. You can see pictures here:

http://chronworks.com/PDP11/

I believe the displays are TIL311. I have the FPE and ExpressPCB design files if anyone is interested. It's not the lowest cost route, but the look good and you can do a lot of customization.

len
 
8008guy,

That looks lovely. Very nice work.

What chassis is that? It looks similar in size and arrangement to my BA23 but is clearly different based on the hinge along the bottom and 8 vs 4 mounting screws per bulkhead section. Since it appears you cut out strips of metal to turn four small slots into one large slot, I'm assuming it's re-purposed from something else?

I too use PCB material for prototyping and it's fantastic stuff. Cheap on eBay, no sparking when used with the table saw, easy to join with a soldering iron, etc. I use it for everything from panels to complete enclosures.

Aaron
 
I bought it as an 11/23. I think it was some sort of industrial controller. The back extended cover with the fold down panel makes it nice to work on. She's a fine machine.!
 
8008guy said:
When I built my 11/83 I made my own cab kit, SLU control diagnostic panel, and serial port bulk heads. You can see pictures here:

http://chronworks.com/PDP11/

I believe the displays are TIL311. I have the FPE and ExpressPCB design files if anyone is interested. It's not the lowest cost route, but the look good and you can do a lot of customization.

len
Click to expand...
Hi, I want to build diagnostic pcb for 11/83. Can you share the schematics in pdf ? I have no way to open your *.sch. Thank you in advance.
 
Theoretically, the .sch files can be opened in either Eagle or KiCad. Also the .pcb files too. The .fpd files are possible from Front Panel Designer but I can't tell. Just did a quick Google of the name to find this out.
 
reinhardtjh said:
Theoretically, the .sch files can be opened in either Eagle or KiCad. Also the .pcb files too. The .fpd files are possible from Front Panel Designer but I can't tell. Just did a quick Google of the name to find this out.
Click to expand...
I have tried both KiCad and Eagle but none of them can open the *.sch file. I don't have OrCAD to try so I am not able to see the *.sch file. How was the original *.sch file created ?
 
cmao said:
I have tried both KiCad and Eagle but none of them can open the *.sch file. I don't have OrCAD to try so I am not able to see the *.sch file. How was the original *.sch file created ?
Click to expand...
Looking at his profile, 8008guy hasn't been active here since Feb 10, 2022 so a private message to him might be required, if he's even still around.
 
8008guy wrote above ... "I have the FPE and ExpressPCB design files if anyone is interested."

The .fpd files look to be FrontPanelDesigner design files; their software opens the .fpd files and they seem to be appropriate.

www.expresspcb.com has their own software for PCB design (it may be a customized version of something) so you may need to go to their site, register, download the tools, and then get to open and look at the .sch and .pcb files. Their prices for small proto are way out of wack compared to even OSHpark much less JLCPCB.
 
Some of his other schematics on the website appear to have been generated with ExpressSCH.

Maybe this thing?
expresssch.apponic.com

ExpressSCH Free Download

ExpressSCH Free Download - Free and easy to use software for Schematic Design tasks.
expresssch.apponic.com expresssch.apponic.com
 
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