help needed: problem with UNIBUS access on my PDP-11/70

From: Gooijen H <>
Date: Thu Jul 11 08:48:01 2002

Thanks for the advice, Tom.
I knew I had forgotten a few things.

> Have you tried to read the DL11-W status register?
> Do you only get the PAUSE on a deposit?

Did a reset and then EXAM on 1777560 (CSR) --> PAUSE goes on

> As you indicate, checking the power supply voltages is
> an important first step.

Agreed, but I could not do that yesterday evening when I
thought of it, because the washing machine was also running ...

> It sounds like you might have a bus request/grant jumper problem or
> problem in the CPU hardware. Since you are using slot 40 (the first
> UNIBUS slot) for your DL11-W, it would seem that the problem would
> be either in the MASSBUS jumpers or a CPU hardware problem. Of
> course, it could also be a backplane wire problem.

Looks like it :-(

> Have you tried to execute a very simple program such as jump to
> self (0777) by depositing that value at location 01000 and starting
> there? This is a good basic CPU test.

Yes, that was the other test I forgot to write.
This test is also succesfull.

> Do you have a KM11 diagnostic board? Using the KM11, you can
> cycle through the microcode flows listed in the printset. This will
> help you diagnose the problem at a finer level then just watching
> the pause lamp turn on. Of course, you will likely need a set of
> board extenders and minimally an o-scope as well. If you don't
> have a KM11 and want to build one, check out the one I built here:

Nice pages. Had seen them before, but lost the URL ...
I hope that I do not have to dig in that deep, but I have a quad and
a double sized extender board and a good Tektronix 465.
If building the KM11 was the problem, I did not have a problem.
To build something as simple as that is a "piece of cake".

- Henk.

> At 09:31 AM 7/11/2002 +0200, you wrote:
> >Hi all.
> >
> >I am having trouble with my 11/70 because it works only partial.
> >Since things are quiet on the list, I have something to ask.
> >It is a long story, but as said on the list this week, the more
> >info you give, the less not relevant suggestions are typed.
> >
> >First the description of the machine.
> >The machine has only all CPU boards (with FP), the DL11-W and
> >3 MASSBUSS interfaces. The fourth MASSBUS interface has in the
> >correct slot a G727. All other UNIBUS slots have a G727 in the
> >card position D. The MOS memory box is also connected to the CPU.
> >
> >This is what I have done so far.
> >When I turn on the machine everything "looks" fine. With the switch
> >ENABLE/HALT on HALT and pressing START, the machine sort of resets.
> >With the panel I can dump data in the MOS memory at address 00000000.
> >I did this also at 00001000 and 00010000. It 'works' and when I read
> >the contents back from those addresses, it is the correct data.
> >So, my first conclusion is that (part of) the CPU is OK and that the
> >address and data path to the MOS memory and the MOS memory box itself
> >are all OK as well.
> >
> >Here is the part that worries me.
> >In slot #40 (IIRC) is the DL11-W (M7856) console interface.
> >I am trying to write to the transmit buffer address (XBUF -
> 17777566).
> >I set the knobs on the 11/70 console to "CONS PHY" and "DATA
> >so that the address on the switches is the real physical address and
> >the data on the switches is what I want to store.
> >After the reset of the machine (HALT/START) I set the switches to
> >17777566, and press LOAD ADRS. On the ADDRESS leds appears 17777566.
> >Now, I set the switches to 00000071 (should give a "9" on the VT220).
> >When I toggle the DEP button, the PAUSE led goes on.
> >According to the handbook that means the the CPU tries to finish the
> >instruction as far as possible and then waits for an event to finish.
> >The event could be (I assume) an interrupt or, in this case, access
> >to the UNIBUS section.
> >
> >Next test was checking the DL11-W interface.
> >First I switched on my 11/34C. With address 165020/START, I get the
> >dump of the registers on the VT102. So, I mad sure that the M7856
> >in the 11/34C is OK.
> >Now, I swapped the M7856 of the 11/70 with the M7856 of the 11/34C.
> >First, I started the 11/34C again. I get the register dump on the
> >screen. So, the M7856 from the 11/70 was OK.
> >Just to make sure I tried the 11/70 again (with M7856 of the 34C),
> >but I get the same result: PAUSE led goes on.
> >
> >Yesterday, I had a long conversation on the phone with Edward. We
> >talk about all kind of (PDP-11) things, and also the 11/70 problem.
> >One suggestion was that the UNIBUS map is not yet initialised, and
> >that would cause the UNIBUS accesses to fail. My guess is that when
> >the console panel knob is set to "CONS PHY", I have full access to
> >all addresses without any mapping taking place. Is this correct?
> >
> >Anyway, to test the "UNIBUS map initialisation" theory, I read the
> >M9312 bootstrap manual. The 11/70 (and 11/60) have a different PROM
> >that stores the diagnostics. The 11/04--11/55 PROM also contains a
> >console monitor, but the 60 and 70 PROM only has diagnostics.
> >The manuals says to load address 17765744, then set the switches
> >8-0 to the device code and then press START.
> >I checked the M9312 to look at the diag PROM. According the M9312
> >manual the PROM code must be 248F1 (IIRC) for the 11/04-11/55, and
> >233F1 for the 11/60-11/70. My M9312 has a PROM with code 616F1.
> >Is that a new type for the 11/70? The M9312 is the card that was
> >in the 11/70 when I got it, and another 11/70 (with remote console)
> >that I have has the same PROM. Edward's 11/70's (he has also 2)
> >one has a 233F1, the other has a 616F1.
> >So, I did that test, but the PAUSE led goes on again.
> >
> >Trying to boot from an RX01 should need at least the RX11 card in
> >a UNIBUS slot ... I did that, so I put the M7846 in slot 41 (IIRC),
> >next to the DL11-W. Tried the test again: 17765744 - LOAD ADRS - set
> >the device code on switches 8 to 0 - START. Alas, PAUSE on again.
> >
> >What puzzles me is the "device code" you must set on the 9 least
> >significant switches. I have set that to 170 as that are the LSB's
> >of the start address fro the bootstrap of the RX11. Is that correct?
> >
> >Come to think of the good advice from Tony: I will check the
> >power supply voltages this evening. Especially the one that supplies
> >the cards that deal with the UNIBUS section ...
> >
> >tnx for reading all this,
> >and TIA for all responses,
> >
> >- Henk.
Received on Thu Jul 11 2002 - 08:48:01 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:35:01 BST