Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/27/2018 10:29 PM, allison via cctalk wrote:

FYI all this is covered in the BA123/microVAC manuals.  Seriously, if
your not familiar with Qbus and microVAX boxes
RTFM and as many as you can find.


The 630QB tech manual seems to be pretty comprehensive, and I have digested 
that one now, I think :-)


My RD53 is definitely unwell, though - sometimes the speed fluctuates, and 
other times it sounds like it's stable (and I can hear the heads move) but 
talking to it is a no-go. I've no idea what (if anything) might be on it 
anyway, though - as set up when I got it, it was in the second drive bay 
(and hooked up via some rather flaky non-DEC cables)


I'm not sure at the moment where I want to proceed from here; net-booting 
might be an option, but I'm not sure if I have any transceivers on this 
side of the Atlantic.


cheers

Jules

Re: DEC H7260 PSU fault

[Antonio Carlini via cctalk]

On 27/01/18 23:38, Jules Richardson via cctalk wrote:



With the drive actually hooked up to the controller, I'm getting "?54 
RETRY" messages when it's trying to boot - however, I'm not entirely 
sure what device it's trying to boot from! Maybe it's attempting the 
TK50, or via Ethernet. I still need to read up on that and work out 
how to force it to attempt a disk boot.




B DUA0

should do it (although you may have yours set up for DUA1 or whatever 
depending on the drive jumpers).




One other issue is that the RD53 was in the second bay (and hooked up 
to the associated cables) - it makes me wonder if it was just an 
auxiliary disk, and the system originally had another drive in the 
first bay (containing actual OS) which has been removed.




I think you get a different message if the disk is there but it has no 
valid boot block.


If you had a later CPU (say the KA650) and anything other than the very 
earliest ROM (which may never have made it out to the field) then you
get a bunch of additional commands (like SHOW DEVICE) which would help 
diagnose what's what. You would be able to tell whether the M7555

was visible at the correct address, for example.

The suggestion of booting it as a satellite from a VMS cluster node is a 
good idea (although if you've never set this up before then it may take you

some time to get it set up properly). SIMH makes this quite easy I think.

Antonio


--
Antonio Carlini
arcarl...@iee.org

Re: DEC H7260 PSU fault

[allison via cctalk]

On 01/27/2018 12:04 PM, Jules Richardson via cctalk wrote:
> On 01/26/2018 07:15 PM, Jules Richardson via cctalk wrote:
>> After that... well, I need to work out how to get the entire supply
>> assembly to start up while it's open, so that I can work on it
>> outside the
>> machine - then I can at least start looking for differences between
>> the two
>> supplies (boy, are those things complex, but maybe I'll get lucky and
>> it's
>> a bad solder joint or cap somewhere)
>
> OK, now I feel like an idiot :-)
>
> I started looking into this, and found that neither PSU would do
> anything without being plugged into the (currently unpopulated)
> backplane. My initial assumption was that there was some interaction
> between the backplane and the "other" wires between it and the PSUs
> (i.e. the ones that don't carry +5V or +12V).
>
> However, on a whim (and I really don't know why I did this) I plugged
> the +5V PSU connectors up to the backplane, but left the others
> (carrying +12V and the other signals) unplugged. Doing that, things
> behaved as before - the top PSU started operating normally, and the
> lower PSU started putting out around 2.5V.
>
> It got me wondering though - maybe it was simply a load issue, and
> with my dummy loads I was right at the (lower) limit for the PSU
> regulation to work; perhaps I had just enough for the top PSU to
> operate normally (but only with the backplane hooked up too) and the
> lower PSU (for whatever reason) wanted just that little bit more than
> the top one.
>
> Anyway, I tweaked my loads to draw a little more current - and bingo!
> I'm now getting stable +5V and +12V outputs on both PSUs, a working
> card cage fan, and the DC OK light comes on.
>
> So, in summary... with no load at all, the PSUs do nothing, but with
> *some* load they either work OK, or the regulation is goofy and the
> outputs are low.
>
> Time to add CPU/memory in, wire up a console cable and see what
> happens, I guess.
>
> cheers
>
> Jules
>
The PSUs used are a switching type and do not behave well with out about
a 5-10% load as a minimum.  They must have a load.

NOTE: the door switch does only one thing and that is to run the fans at
100% when the covers are off.  When they are
on then the switch allows the fan speed to be controlled by temperature.

FYI all this is covered in the BA123/microVAC manuals.  Seriously, if
your not familiar with Qbus and microVAX boxes
RTFM and as many as you can find.

Allison

Re: DEC H7260 PSU fault

[Jon Elson via cctalk]

On 01/27/2018 02:43 PM, Jules Richardson via cctalk wrote:


Well, there's someone's hand-written sticker on the top 
saying it's a lowly RD51 - however the actual p/n sticker 
says it's an RD53-A and the defect table lists it as 
ST506, 85MB.


Of course it probably doesn't work anyway ;-)

The likelihood of a 30+ year old MFM hard drive working is 
pretty small.  If it DOES work, get the data off it as soon 
as possible, the grease in the bearings are likely to have 
turned into gunk and it won't last.
If you start with just the M7606 - CPU and the M7608 - 
4MB ram once
you get a console cable built it shouldn't be too hard to 
get some

basic signs of life.


Yes, that's where I'm at right now...

Console default is 8 data bits, 1 stop bit and no parity 
(at whatever speed the switch is set to), correct?


I'm getting an alternating F and 9 on the hex LED diag 
display on the console panel, no output at all on my 
terminal, and the M7606 starts with 4 solid red LEDs, then 
a solid green, then the middle pair of the red LEDs start 
a simultaneous slow flash on/off (while the outer two plus 
the green remain steady)


MM, that doesn't sound good at all.  The single LED on the 
console panel is supposed to count down from F as it runs 
through the on-board diags.  It is supposed to send a 2-line 
(I think) description of the board rev level and ROM 
firmware level, and then do something like this:


F.E.D.CB.A.9.87  (this is 
the memory test, and can take a LONG time) and then continue,
finally leaving you with a console prompt or a boot or boot 
failure message.


Jon

Re: DEC H7260 PSU fault

[Peter Coghlan via cctalk]

With the drive actually hooked up to the controller, I'm getting "?54
RETRY" messages when it's trying to boot - however, I'm not entirely sure
what device it's trying to boot from! Maybe it's attempting the TK50, or
via Ethernet. I still need to read up on that and work out how to force it
to attempt a disk boot.



On a VAXStation/MicroVAX 2000 (which could behave the same as or completely
differently to an MV-II), "?54 RETRY" is what you get when attempting to boot
from the network when nothing is responding (also, if I recall correctly, so
take this with a giant pinch of salt...)

Regards,
Peter Coghlan.

RE: DEC H7260 PSU fault

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jules
> Richardson via cctalk
> Sent: 27 January 2018 23:39
> To: General Discussion: On-Topic and Off-Topic Posts
<cctalk@classiccmp.org>
> Subject: Re: DEC H7260 PSU fault
> 
> On 01/27/2018 04:02 PM, Ethan Dicks wrote:
> > On Sat, Jan 27, 2018 at 4:34 PM, Jules Richardson via cctalk
> > <cctalk@classiccmp.org> wrote:
> >> Success!
> >
> >
> > Congratulations!
> 
> ish... :-)
> 
> It seems that my DHV11 board is bad - the system stalls on the PSU tests
with it
> plugged in.
> 
> The TK50 drive sits there with a rapidly-flashing light (I saw someone
saying
> that's likely the tape feed band or just dirty heads, so it might be
fixable).
> 
> The RD53 drive... hmm. I tried powering it without it plugged in, just to
see if it
> at least sounded healthy; it spun up to a "sensible-sounding"
> speed for maybe 15 seconds, then spun down again. I tried again, and it
> remained spun-up, but the initial spin-down was hardly encouraging.
> 

Did you hear the heads move? Spinning up and down again likely means it
couldn't find the first track. Very likely to be stiction from the rubber
bumper inside which has turned to goo.

> With the drive actually hooked up to the controller, I'm getting "?54
RETRY"
> messages when it's trying to boot - however, I'm not entirely sure what
device
> it's trying to boot from! Maybe it's attempting the TK50, or via Ethernet.
I still
> need to read up on that and work out how to force it to attempt a disk
boot.
> 
> One other issue is that the RD53 was in the second bay (and hooked up to
the
> associated cables) - it makes me wonder if it was just an auxiliary disk,
and the
> system originally had another drive in the first bay (containing actual
OS) which
> has been removed.

Can't remember exactly, but not necessarily. You need to try commands like
BOOT DUA0/1/2/3, but if the heads are sticking you won't get far. I would
suggest net booting the machine as a satellite and then seeing if the local
disk is visible to the OS.

> 
> > Just be sure to follow the grant chain
> 
> Yup, I *think* I've got my head around how that works! (along with the
special
> slots for CPU/RAM)
> 
> cheers
> 
> Jules

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/27/2018 04:02 PM, Ethan Dicks wrote:

On Sat, Jan 27, 2018 at 4:34 PM, Jules Richardson via cctalk
 wrote:

Success!



Congratulations!


ish... :-)

It seems that my DHV11 board is bad - the system stalls on the PSU tests 
with it plugged in.


The TK50 drive sits there with a rapidly-flashing light (I saw someone 
saying that's likely the tape feed band or just dirty heads, so it might be 
fixable).


The RD53 drive... hmm. I tried powering it without it plugged in, just to 
see if it at least sounded healthy; it spun up to a "sensible-sounding" 
speed for maybe 15 seconds, then spun down again. I tried again, and it 
remained spun-up, but the initial spin-down was hardly encouraging.


With the drive actually hooked up to the controller, I'm getting "?54 
RETRY" messages when it's trying to boot - however, I'm not entirely sure 
what device it's trying to boot from! Maybe it's attempting the TK50, or 
via Ethernet. I still need to read up on that and work out how to force it 
to attempt a disk boot.


One other issue is that the RD53 was in the second bay (and hooked up to 
the associated cables) - it makes me wonder if it was just an auxiliary 
disk, and the system originally had another drive in the first bay 
(containing actual OS) which has been removed.



Just be sure to follow the grant chain


Yup, I *think* I've got my head around how that works! (along with the 
special slots for CPU/RAM)


cheers

Jules

Re: DEC H7260 PSU fault

[Ethan Dicks via cctalk]

On Sat, Jan 27, 2018 at 5:13 PM, Glen Slick  wrote:
>> Just be sure to follow the grant chain - the BA23 and BA123 have a
>> hybrid backplane where the first few slots are CD slots and the rest
>> are serpentine (3 CD slots for BA23, 5 CD slots for BA123).
>
> First 4 slots of a BA123 are Q22/CD, not the first 5. Page 22 of the
> PDF, page 1-11, Figure 1-9 Backplane Grant Continuity of the same
> manual referenced above.

Good catch.  I looked it up because I remembered that it was different
but I misread one of the links that mentioned slot 5... slot 5 is the
_first_ Q22 slot.  1-4 are Q22/CD.

Thanks for spotting this.

-ethan

Re: DEC H7260 PSU fault

[Glen Slick via cctalk]

On Sat, Jan 27, 2018 at 2:02 PM, Ethan Dicks via cctalk
 wrote:
> On Sat, Jan 27, 2018 at 4:34 PM, Jules Richardson via cctalk
>  wrote:
>> Success!
>
> Congratulations!
>
>> I'd left the rear panel console settings how they were when I got the
>> machine, I mean 'T' for terminal, right? Wrong... arrow for terminal, 'T'
>> for "sit there alternating between F and 9, and driving Jules insane" ;)
>
> 'T' is 'Loop Test'...

http://www.bitsavers.org/pdf/dec/vax/630/
AX-GLBAA-MN_MicroVAX_II_630QB_Technical_Manual_Nov85.pdf

Page 37 of the PDF, page 2-6, Figure 2-2, CPU Patch Panel Insert.
Might be helpful to print out a copy of that figure and tape it to the
back of the BA123. I can never remember what the rotary and toggle
switch positions mean.


> Just be sure to follow the grant chain - the BA23 and BA123 have a
> hybrid backplane where the first few slots are CD slots and the rest
> are serpentine (3 CD slots for BA23, 5 CD slots for BA123).

First 4 slots of a BA123 are Q22/CD, not the first 5. Page 22 of the
PDF, page 1-11, Figure 1-9 Backplane Grant Continuity of the same
manual referenced above.

Re: DEC H7260 PSU fault

[Ethan Dicks via cctalk]

On Sat, Jan 27, 2018 at 4:34 PM, Jules Richardson via cctalk
 wrote:
> Success!


Congratulations!

> I'd left the rear panel console settings how they were when I got the
> machine, I mean 'T' for terminal, right? Wrong... arrow for terminal, 'T'
> for "sit there alternating between F and 9, and driving Jules insane" ;)

'T' is 'Loop Test'...

http://www.mcmanis.com/chuck/computers/vaxen/panels.htm
http://www.vaxination.ca/vms/microvax/uVAXII_HWinfo_Sep87.pdf

> I'm getting console output now, and it's getting down to trying to load
> system software
>
> Will throw boards back in there and see what happens...

Just be sure to follow the grant chain - the BA23 and BA123 have a
hybrid backplane where the first few slots are CD slots and the rest
are serpentine (3 CD slots for BA23, 5 CD slots for BA123).

http://web.frainresearch.org:8080/projects/pdp-11/chassis.php
http://vaxarchive.org/hardware/qbus1.html

-ethan

Re: DEC H7260 PSU fault

[Ethan Dicks via cctalk]

On Sat, Jan 27, 2018 at 4:34 PM, Jules Richardson via cctalk
 wrote:
> Success!

Congratulations!

> I'd left the rear panel console settings how they were when I got the
> machine, I mean 'T' for terminal, right? Wrong... arrow for terminal, 'T'
> for "sit there alternating between F and 9, and driving Jules insane" ;)

'T' is Test...
> I'm getting console output now, and it's getting down to trying to load
> system software before failing (understandably, because I don't have any
> other boards in there right now)
>
> Will throw boards back in there and see what happens...
>
> J.
>
>
>

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/27/2018 03:02 PM, Jules Richardson via cctalk wrote:

OK, looking at the 630QB tech manual now, which seems to be where these
were lifted from... and of course it points out that the LEDs on the M7606
correspond to the hex codes on the panel (i.e. my four red LEDs with the
middle pair flashing on and off equate to the alternating F-9 I'm seeing on
the hex LED)


Success!

I'd left the rear panel console settings how they were when I got the 
machine, I mean 'T' for terminal, right? Wrong... arrow for terminal, 'T' 
for "sit there alternating between F and 9, and driving Jules insane" ;)


I'm getting console output now, and it's getting down to trying to load 
system software before failing (understandably, because I don't have any 
other boards in there right now)


Will throw boards back in there and see what happens...

J.

Re: DEC H7260 PSU fault

[Glen Slick via cctalk]

On Sat, Jan 27, 2018 at 1:02 PM, Jules Richardson via cctalk
 wrote:
>
> OK, looking at the 630QB tech manual now, which seems to be where these were
> lifted from... and of course it points out that the LEDs on the M7606
> correspond to the hex codes on the panel (i.e. my four red LEDs with the
> middle pair flashing on and off equate to the alternating F-9 I'm seeing on
> the hex LED)
>
> The green LED on the CPU board is 'DC OK' and I'm also getting a green 'DC
> OK' on the front of the machine, and it seems odd those would be lit if
> there were a DC fault... but who knows. No explanation of the flashing
> codes, either; the manual seems to imply that it steps through in sequence
> down from 'F' and will stop when there's a fault.

Do you have a scope that you can use to monitor the BDCOK line? If it
is periodically dropping low that would cause a loop of the processor
halting and resetting. That could be happening fast enough that the DC
OK LED appears to stay on continuously.

That would be the same as periodically pressing the Restart button on
the front panel, which works by pulling down the BDCOK line. (See the
BA123-A Front Panel sheet, page 115 of the maintenance print sheet PDF
MP02071_630QB_Mar85.pdf)

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/27/2018 12:51 PM, Adrian Graham via cctalk wrote:

Anyway, I tweaked my loads to draw a little more current - and bingo!
I'm now getting stable +5V and +12V outputs on both PSUs, a working
card cage fan, and the DC OK light comes on.


This is good, particularly since my own BA123 has been sat in 3 garages
then a utility room since 1998, you’re making me think it MIGHT just
power up without any issues.


Hey, my rifa caps haven't exploded yet, either! :-D

See reply to Glen, though - I'm getting an alternating F-9 on the hex 
display / CPU diag LEDs, which the docs don't mention as being a 'thing'; 
they seem to imply that startup codes should decrease from 'F' and stop if 
there's a fault, not go into a condition where they alternate.

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/27/2018 11:44 AM, Glen Slick via cctalk wrote:

On Sat, Jan 27, 2018 at 9:04 AM, Jules Richardson via cctalk
 wrote:


Time to add CPU/memory in, wire up a console cable and see what happens, I
guess.


With the PSU working everything else should be easier to get going after that.

Did you figure out what the hard drive is? A working RD54 would be
nice and probably worth more than any of the boards.


Well, there's someone's hand-written sticker on the top saying it's a lowly 
RD51 - however the actual p/n sticker says it's an RD53-A and the defect 
table lists it as ST506, 85MB.


Of course it probably doesn't work anyway ;-)


If you start with just the M7606 - CPU and the M7608 - 4MB ram once
you get a console cable built it shouldn't be too hard to get some
basic signs of life.


Yes, that's where I'm at right now...

Console default is 8 data bits, 1 stop bit and no parity (at whatever speed 
the switch is set to), correct?


I'm getting an alternating F and 9 on the hex LED diag display on the 
console panel, no output at all on my terminal, and the M7606 starts with 4 
solid red LEDs, then a solid green, then the middle pair of the red LEDs 
start a simultaneous slow flash on/off (while the outer two plus the green 
remain steady)


This is just with the M7606 CPU and M7808 memory plugged in, nothing else 
(apart from the half-height board at the end of the backplane which 
distributes signals to the RD53) - oh and the LEDs were observed with the 
card cage cover switch held down, so 'under normal operating conditions'.


For console cable wiring I'm using the following ref:

  http://www.mcmanis.com/chuck/computers/vaxen/panels.htm

There's a ref here for the status codes:

https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c01608433

.. however, I'm not sure what the alternating codes mean; 'F' seems to be 
power-related, but I don't know why the CPU would proceed if it thought 
there was a power fault, and '9' is related to terminal ID, but it seems to 
suggest it should automatically continue after 6 seconds.


cheers

Jules

Re: DEC H7260 PSU fault

[Adrian Graham via cctalk]

> On 27 Jan 2018, at 17:04, Jules Richardson via cctalk  
> wrote:
> 
> On 01/26/2018 07:15 PM, Jules Richardson via cctalk wrote:
>> After that... well, I need to work out how to get the entire supply
>> assembly to start up while it's open, so that I can work on it outside the
>> machine - then I can at least start looking for differences between the two
>> supplies (boy, are those things complex, but maybe I'll get lucky and it's
>> a bad solder joint or cap somewhere)
> 
> OK, now I feel like an idiot :-)

We’ve all been there including me earlier! When you have two PSUs in a machine 
but only one is connected to the mains make sure you don’t connect a flying 
lead from the OTHER one and spend 2 hours wondering why the bloody thing 
doesn’t work.

> Anyway, I tweaked my loads to draw a little more current - and bingo! I'm now 
> getting stable +5V and +12V outputs on both PSUs, a working card cage fan, 
> and the DC OK light comes on.

This is good, particularly since my own BA123 has been sat in 3 garages then a 
utility room since 1998, you’re making me think it MIGHT just power up without 
any issues. 

And THEN I can tackle the RL02 that’s sat on top of it… being able to read my 
own source code from the 80s would be a special thing indeed.

—
Adrian/Witchy
Binary Dinosaurs - Celebrating Computing History from 1972 onwards
w: binarydinosaurs.co.uk t: @binarydinosaurs
f: facebook.com/binarydinosaurs

Re: DEC H7260 PSU fault

[Glen Slick via cctalk]

On Sat, Jan 27, 2018 at 9:04 AM, Jules Richardson via cctalk
 wrote:
>
> Time to add CPU/memory in, wire up a console cable and see what happens, I
> guess.

With the PSU working everything else should be easier to get going after that.

Did you figure out what the hard drive is? A working RD54 would be
nice and probably worth more than any of the boards.

If you start with just the M7606 - CPU and the M7608 - 4MB ram once
you get a console cable built it shouldn't be too hard to get some
basic signs of life. The M7606 KA630 CPU console firmware is fairly
limited compared to the subsequent M7620 KA650 and M7625 KA655. It
doesn't have a SHOW command to show memory and device details, and
doesn't even have a HELP command to list available commands.

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/26/2018 07:15 PM, Jules Richardson via cctalk wrote:

After that... well, I need to work out how to get the entire supply
assembly to start up while it's open, so that I can work on it outside the
machine - then I can at least start looking for differences between the two
supplies (boy, are those things complex, but maybe I'll get lucky and it's
a bad solder joint or cap somewhere)


OK, now I feel like an idiot :-)

I started looking into this, and found that neither PSU would do anything 
without being plugged into the (currently unpopulated) backplane. My 
initial assumption was that there was some interaction between the 
backplane and the "other" wires between it and the PSUs (i.e. the ones that 
don't carry +5V or +12V).


However, on a whim (and I really don't know why I did this) I plugged the 
+5V PSU connectors up to the backplane, but left the others (carrying +12V 
and the other signals) unplugged. Doing that, things behaved as before - 
the top PSU started operating normally, and the lower PSU started putting 
out around 2.5V.


It got me wondering though - maybe it was simply a load issue, and with my 
dummy loads I was right at the (lower) limit for the PSU regulation to 
work; perhaps I had just enough for the top PSU to operate normally (but 
only with the backplane hooked up too) and the lower PSU (for whatever 
reason) wanted just that little bit more than the top one.


Anyway, I tweaked my loads to draw a little more current - and bingo! I'm 
now getting stable +5V and +12V outputs on both PSUs, a working card cage 
fan, and the DC OK light comes on.


So, in summary... with no load at all, the PSUs do nothing, but with *some* 
load they either work OK, or the regulation is goofy and the outputs are low.


Time to add CPU/memory in, wire up a console cable and see what happens, I 
guess.


cheers

Jules

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/25/2018 09:29 PM, Jules Richardson via cctalk wrote:

On 01/25/2018 07:16 PM, Glen Slick via cctalk wrote:

On Thu, Jan 25, 2018 at 3:06 PM, Jules Richardson via cctalk

OK, the top PSU of the pair in this machine appears to be healthy. The
bottom one, however, sits at around 2.5V on both the +5V and +12V outputs.
That's without any cards, and the card-cage fan / temperature sensor
unplugged, i.e. just with my dummy loads in place, so it looks like that
PSU
has issues (oh, and I tried decoupling the PSU from the backplane and
loading it via the drive connector, so it doesn't appear to be a backplane
issue).



Looking here at page 107 of the maintenance print set, BA123-A Basic
Enclosure Power Harness Wiring Diagram
http://www.bitsavers.org/pdf/dec/vax/630/MP02071_630QB_Mar85.pdf

Did you disconnect the wiring harness from J10 completely? If you
disconnected the temperature sensor module or the card-cage door
interlock switch I would expect that the power supply might not
operate normally.


I believe that I tried it both connected and disconnected, with no change
in behavior, but I'll double-check (not until tomorrow evening now, though).


OK, I just verified that - it doesn't matter whether the J10 harness is 
connected or not, same behavior.


The outputs of the main relay/regulator board which feeds both supplies 
appear to be the same, so I don't think that's at fault. I think my next 
step is to trace out the wiring for the temp sensor, along with that fourth 
"fan control" PCB within the PSU module so that I can better understand 
what it's trying to do.


After that... well, I need to work out how to get the entire supply 
assembly to start up while it's open, so that I can work on it outside the 
machine - then I can at least start looking for differences between the two 
supplies (boy, are those things complex, but maybe I'll get lucky and it's 
a bad solder joint or cap somewhere)


cheers

Jules

Re: DEC H7260 PSU fault

[Antonio Carlini via cctalk]

On 25/01/18 23:47, Rob Jarratt via cctalk wrote:



I doubt it. For the H7864 from the BA23 MicroVax II Enclosure I couldn't
find anything and in the end made my own schematic.



If it was externally sourced then DEC probably didn't have a schematic.

That was the case with the DEMSA (iirc) and also with various PSUs from

another company I worked for.


So doing rolling your own (if you indeed do need one) may be the only way.


Antonio

--
Antonio Carlini
arcarl...@iee.org

RE: DEC H7260 PSU fault

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Glen Slick
> via cctalk
> Sent: 26 January 2018 01:17
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
> Subject: Re: DEC H7260 PSU fault
> 
> On Thu, Jan 25, 2018 at 3:06 PM, Jules Richardson via cctalk
> <cctalk@classiccmp.org> wrote:
> > Hi all,
> >
> > I mentioned this in the thread where I'd asked about basic Microvax II
> > info, but it may have got lost in traffic...
> >
> > The machine's H7260 PSU is somewhat unwell - one of the internal
> > +5/12V supplies appears to be healthy, but the other has outputs which
> > are sitting at around 2.5V (both on the 5V and 12V rails) under a test load.
> >
> 
> Previously you also said:
> 
> > OK, the top PSU of the pair in this machine appears to be healthy. The
> > bottom one, however, sits at around 2.5V on both the +5V and +12V outputs.
> > That's without any cards, and the card-cage fan / temperature sensor
> > unplugged, i.e. just with my dummy loads in place, so it looks like
> > that PSU has issues (oh, and I tried decoupling the PSU from the
> > backplane and loading it via the drive connector, so it doesn't appear
> > to be a backplane issue).
> >
> 
> Looking here at page 107 of the maintenance print set, BA123-A Basic
> Enclosure Power Harness Wiring Diagram
> http://www.bitsavers.org/pdf/dec/vax/630/MP02071_630QB_Mar85.pdf
> 
> Did you disconnect the wiring harness from J10 completely? If you disconnected
> the temperature sensor module or the card-cage door interlock switch I would
> expect that the power supply might not operate normally.
> 
> I forget what the card-cage door interlock switch does, whether it prevents 
> the
> power supply from fully powering up, or if the power supply does fully power
> up but also turns the fans on full blast if the card-cage door is open which
> disrupts the normal cooling airflow.

If the door is open the fans run full blast.

> I would check what my BA123 does, but that would require too much moving of
> stuff about at the moment to get working space around it.

Re: DEC H7260 PSU fault

[Jules Richardson via cctalk]

On 01/25/2018 07:16 PM, Glen Slick via cctalk wrote:

On Thu, Jan 25, 2018 at 3:06 PM, Jules Richardson via cctalk

OK, the top PSU of the pair in this machine appears to be healthy. The
bottom one, however, sits at around 2.5V on both the +5V and +12V outputs.
That's without any cards, and the card-cage fan / temperature sensor
unplugged, i.e. just with my dummy loads in place, so it looks like that PSU
has issues (oh, and I tried decoupling the PSU from the backplane and
loading it via the drive connector, so it doesn't appear to be a backplane
issue).



Looking here at page 107 of the maintenance print set, BA123-A Basic
Enclosure Power Harness Wiring Diagram
http://www.bitsavers.org/pdf/dec/vax/630/MP02071_630QB_Mar85.pdf

Did you disconnect the wiring harness from J10 completely? If you
disconnected the temperature sensor module or the card-cage door
interlock switch I would expect that the power supply might not
operate normally.


I believe that I tried it both connected and disconnected, with no change 
in behavior, but I'll double-check (not until tomorrow evening now, though).


I need to look at how the signals on J10 interact with the entire PSU 
internals - it certainly seems to get a -15V feed from the lower PSU of the 
pair (the one that's causing me issues), but many of the wires run to the 
fourth, small PCB that's in the entire PSU assembly; I assume that one 
handles fan control as it also connects the the PSU fan and to J7 (which 
supplies the fan in the mass storage area)


It seems strange to me that one PSU of the pair would sit in an 
under-voltage condition due to a sensor issue while the other one would 
continue to operate normally, though; at this stage I think it's more 
likely that I've got a PSU fault (or a fault with the rectifier/relay board 
which supplies it - I'm most of the way through tracing a schematic for 
that board, so I can test some voltages sensibly tomorrow)


Will let you know how it goes...

Jules

Re: DEC H7260 PSU fault

[Glen Slick via cctalk]

On Thu, Jan 25, 2018 at 3:06 PM, Jules Richardson via cctalk
 wrote:
> Hi all,
>
> I mentioned this in the thread where I'd asked about basic Microvax II info,
> but it may have got lost in traffic...
>
> The machine's H7260 PSU is somewhat unwell - one of the internal +5/12V
> supplies appears to be healthy, but the other has outputs which are sitting
> at around 2.5V (both on the 5V and 12V rails) under a test load.
>

Previously you also said:

> OK, the top PSU of the pair in this machine appears to be healthy. The
> bottom one, however, sits at around 2.5V on both the +5V and +12V outputs.
> That's without any cards, and the card-cage fan / temperature sensor
> unplugged, i.e. just with my dummy loads in place, so it looks like that PSU
> has issues (oh, and I tried decoupling the PSU from the backplane and
> loading it via the drive connector, so it doesn't appear to be a backplane
> issue).
>

Looking here at page 107 of the maintenance print set, BA123-A Basic
Enclosure Power Harness Wiring Diagram
http://www.bitsavers.org/pdf/dec/vax/630/MP02071_630QB_Mar85.pdf

Did you disconnect the wiring harness from J10 completely? If you
disconnected the temperature sensor module or the card-cage door
interlock switch I would expect that the power supply might not
operate normally.

I forget what the card-cage door interlock switch does, whether it
prevents the power supply from fully powering up, or if the power
supply does fully power up but also turns the fans on full blast if
the card-cage door is open which disrupts the normal cooling airflow.
I would check what my BA123 does, but that would require too much
moving of stuff about at the moment to get working space around it.

RE: DEC H7260 PSU fault

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Jules
> Richardson via cctalk
> Sent: 25 January 2018 23:07
> To: xx Classiccmp mailing list <cctalk@classiccmp.org>
> Subject: DEC H7260 PSU fault
> 
> Hi all,
> 
> I mentioned this in the thread where I'd asked about basic Microvax II
info, but
> it may have got lost in traffic...
> 
> The machine's H7260 PSU is somewhat unwell - one of the internal +5/12V
> supplies appears to be healthy, but the other has outputs which are
sitting at
> around 2.5V (both on the 5V and 12V rails) under a test load.
> 
> Initial questions...
> 
> 1) Are schematics are available online? I couldn't find them (either under
the
> DEC p/n or the Astec AA13010 one), but perhaps they're buried in
schematics
> for a specific DEC machine somewhere.
> 


I doubt it. For the H7864 from the BA23 MicroVax II Enclosure I couldn't
find anything and in the end made my own schematic.


> 2) Upon initial glance, the 'first' board of the three in the PSU module
appears
> to be a pair of control relays, bridge rectifiers and capacitors,
supplying +/- DC
> voltages to the two individual PSU boards. Does anyone know if I can
disconnect
> these from the PSU boards safely* and measure their outputs, and if so
what
> voltages I should expect to see? That might be a good initial test before
> pointing a finger at the PSU board associated with the low outputs.
> 
> * I mean without component damage - I expect they might be sitting at a
> significant DC voltage, so there's an obvious personal safety aspect too
;-)
> 
> cheers
> 
> Jules

DEC H7260 PSU fault

[Jules Richardson via cctalk]

Hi all,

I mentioned this in the thread where I'd asked about basic Microvax II 
info, but it may have got lost in traffic...


The machine's H7260 PSU is somewhat unwell - one of the internal +5/12V 
supplies appears to be healthy, but the other has outputs which are sitting 
at around 2.5V (both on the 5V and 12V rails) under a test load.


Initial questions...

1) Are schematics are available online? I couldn't find them (either under 
the DEC p/n or the Astec AA13010 one), but perhaps they're buried in 
schematics for a specific DEC machine somewhere.


2) Upon initial glance, the 'first' board of the three in the PSU module 
appears to be a pair of control relays, bridge rectifiers and capacitors, 
supplying +/- DC voltages to the two individual PSU boards. Does anyone 
know if I can disconnect these from the PSU boards safely* and measure 
their outputs, and if so what voltages I should expect to see? That might 
be a good initial test before pointing a finger at the PSU board associated 
with the low outputs.


* I mean without component damage - I expect they might be sitting at a 
significant DC voltage, so there's an obvious personal safety aspect too ;-)


cheers

Jules