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

From: Gooijen H <>
Date: Fri Jul 12 01:38:01 2002

I measured the voltages at the connected on the backplane yesterday.
They are all fine, but ... the +5V on P2, pins #5 and #6, is 0.6V.
This +5V powers the slots 2-3-4-5 where the floating point sits.

Since I swapped all boards from my 11/70 with remote console with
the boards from the 11/70 with full console I suspected that the
remote console 1/70 had the FP option and the other did not.
Checking ... yes indeed!
To my shame I see that the H744 in position A is in the "remote-70"
and position A in the "console-70" is empty!
Easy to say that FP would not work!
I moved the H744 from the remote-70 to the console-70 and checked
the voltages again. Now, the pins #5 and #6 on P2 also show 4,98 V.

Unfortunately, this installed PSU does not solve the problem.
I still have the PAUSE led on with any access to 1777756x (read/write).

My new question.
When you have an 11/70 without the floating point boards and you want
to install the FP option, you do the following things.
- carefully slide the 4 FP boards in the correct position,
  in the slots 2-3-4-5.
- install an H744 in the upper power supply, position A
  (nearest to the transformer compartment) and connect it to P9.
- is there something else you shuld do ?

- Henk.

> -----Original Message-----
> From: Gooijen H []
> Sent: donderdag 11 juli 2002 9:31
> To: ''
> Subject: help needed: problem with UNIBUS access on my PDP-11/70
> 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 REGISTER"
> 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 Fri Jul 12 2002 - 01:38:01 BST

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