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

From: Gooijen H <>
Date: Fri Jul 12 04:39:00 2002

Ok, many tips to check on this weekend.

> Did you catch your washing machine;-) Just curious what the washing
> machine has to do with checking your power supply voltage? The
> voltages you want to check are the DC +5, +15, -15, etc. Also you
> ought to check the ACLO and DCLO signals. I had a case where the
> regulator board in my lower h7420a was asserting ACLO when in fact
> all of the voltages were fine.

I meant the power supply voltages at the secundary side of course.
As Andreas says, when the washing machine runs, turning on any big
PDP-11 blows the fuse. I have to reset all clock radios and the clock
on the microwave oven.

I definitely will check the DCLO and ACLO signals!
I will use the scope also to check the +5V lines for any ripple.

[.. test with diagnostic PROM on M9312 ..]

> It's not clear to me _when_ PAUSE goes on here. Do you mean that when
> you try to run the code from the boot ROM (i.e. when you press START)
> then the PAUSE LED goes on? Or do you mean that the code runs correctly
> but that even after running it you get a PAUSE when trying to access
> the DL11-W?

To clear things on the question from Tony, when I push the START button
the PAUSE led goes on immediately. I will not get that far that I can
try to access to the DL11-W again.
I will swap the M9302 at the end of the backplane (it is there, I just
forgot to mention it) with an M930.

All slots that need a grant card according to the Field Maintenance
Print Set (FMPS) have one installed. The FMPS shows G727 flip chips for
one slot of the 4 slots per MASSBUS interface that not installed, and
all UNIBUS slots at the end of the backplane.
I had the same experience as Ethan did.
When I removed the TU80 interface from my 11/34C the system hung.
I inserted a double grant card G7273 and all was fine again.

Have I nice weekend,
- Henk.
Received on Fri Jul 12 2002 - 04:39:00 BST

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