SBB power supplies failing slowly

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Phillip Helbig (undress to reply)

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Mar 28, 2022, 5:24:52 AMMar 28
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I've seen this before, about a year ago, then it happened again in
another BA356: Disks go offline and into mount verification, then come
back after a minute or so. The process repeats every ten minutes. Of
course, being VMS, the cluster continues and practically nothing else is
affected, but it is annoying.

Replacing the power supply solves the problem.

I understand that a power supply can fail, but why is it failing in this
manner? Maybe overheating and shutting off then coming back on?

Being VMS, I dismounted the shadow-set members in the box with the flaky
power supply. Thanks to minicopy, things were quickly back to normal
after replacing the power supply. To do that, I turned off the box,
replaced the power supply, and turned it back on. The node whose
system-disk shadow set was in the box didn't crash.

I like VMS.

Now to find a few more replacement power supplies. When collecting
SBBs, I concentrated on disks, and I think that I have enough of them.
Since the first power-supply failure wasn't until about a year ago, I
hadn't explicitly looked for them, but fortunately got a few with BA356
and other SBBs (mostly disks).

I need the Top Gun Blue (that's really the official colour!) 180W
versions. If anyone has any in Scandinavia, Germany, Benelux, England,
Switzerland, Austria, Slovenia, or northwestern Croatia I could probably
collect them sometime this year, probably before autumn. Rest of the
Balkan: next year.

I also plan to be in the southeast USA soon so would be happy to collect
there as well. (Apparently they run on 50 or 60 Hz and anything between
100 and 240 volts.)

It's mainly the power supplies I need, but I'll take any blue SBBs.

Jan-Erik Söderholm

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Mar 28, 2022, 5:55:24 AMMar 28
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PSUs are aging. The electrolytic capacitators are drying out. This will
make the voltages to become more unstable and causing intermitent
issues before going totaly "off". Quite normal, I'd say.

Some makes a buiness out of replacing old capacitors in power supplies
for TV sets and other home/kitchen appliences. I guess that is equially
possible in these PSUs. They are not too modern and should be fine to
work on without special soldering equipment.

Marc J.

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Mar 28, 2022, 11:04:50 AMMar 28
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Le 28/03/2022 à 11:24, Phillip Helbig (undress to reply) a écrit :
> I need the Top Gun Blue (that's really the official colour!) 180W
> versions. If anyone has any in Scandinavia, Germany, Benelux, England,
> Switzerland, Austria, Slovenia, or northwestern Croatia I could probably
> collect them sometime this year, probably before autumn. Rest of the
> Balkan: next year.

Hi,

You need, you could collect, we understood but could you pay for?

Kind regards,
Marc

Scott Dorsey

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Mar 28, 2022, 2:40:45 PMMar 28
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In article <t1rut2$uku$1...@gioia.aioe.org>,
Phillip Helbig (undress to reply) <hel...@asclothestro.multivax.de> wrote:
>I've seen this before, about a year ago, then it happened again in
>another BA356: Disks go offline and into mount verification, then come
>back after a minute or so. The process repeats every ten minutes. Of
>course, being VMS, the cluster continues and practically nothing else is
>affected, but it is annoying.
>
>Replacing the power supply solves the problem.
>
>I understand that a power supply can fail, but why is it failing in this
>manner? Maybe overheating and shutting off then coming back on?

Yes, the supply is likely crowbarring itself. Replace all of the
electrolytic capacitors on the secondary side of the board. While you
are at it, you might pre-emptively replace the kickstart cap since they
are prone to fail in those cabinets.

>Now to find a few more replacement power supplies. When collecting
>SBBs, I concentrated on disks, and I think that I have enough of them.
>Since the first power-supply failure wasn't until about a year ago, I
>hadn't explicitly looked for them, but fortunately got a few with BA356
>and other SBBs (mostly disks).

Just fix it. No reason to replace the whole thing.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Phillip Helbig (undress to reply)

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Mar 28, 2022, 4:26:57 PMMar 28
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In article <6241ce90$0$8906$426a...@news.free.fr>, "Marc J."
<ma...@retronik.fr> writes:

> Le 28/03/2022 à 11:24, Phillip Helbig (undress to reply) a écrit :
> > I need the Top Gun Blue (that's really the official colour!) 180W
> > versions. If anyone has any in Scandinavia, Germany, Benelux, England,
> > Switzerland, Austria, Slovenia, or northwestern Croatia I could probably
> > collect them sometime this year, probably before autumn. Rest of the
> > Balkan: next year.
>
> Hi,
>
> You need, you could collect, we understood but could you pay for?

Depends on the price.

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