Travel and dead Resmed power supply. Coincidence?

[JointPain]

I just got back from a week long visit to Amsterdam.

When I first plugged my Resmed S9 Autoset into the hotel power in Amsterdam, the unit came on, then immediately went off, then on again, off again a few times before staying on. But then it would turn off semi-randomly during the night. This repeated every night and appeared to be getting worse. I assumed it was some quirk of the local / hotel power supply. (No other equipment had problems, but it was all relatively low power.)

But I just got back and now it wouldn't turn on at all. (The power light barely flashes green, then it turns off, and the cycle repeats.)

Fortunately, my battery backup and DC power supply appear to have no issues, so I'll be using them for a few days.

I am thinking it's likely the issue is with the power supply brick. (A new brick has been ordered from our sponsors.) I've traveled with it to many countries with no issues before this.

It is just under two years old.

So, a few questions:

Who else has had a Resmed power brick fail? About how long is their expected lifetime?

Is there any reason to believe the brick starting to fail the first night of my vacation was anything other than a coincidence? I'm thinking that it could have been starting to fail and that the extra voltage was enough to accelerate that process a little.

[Drowsy Dancer]

I just got back from a week long visit to Amsterdam.

When I first plugged my Resmed S9 Autoset into the hotel power in Amsterdam, the unit came on, then immediately went off, then on again, off again a few times before staying on. But then it would turn off semi-randomly during the night. This repeated every night and appeared to be getting worse. I assumed it was some quirk of the local / hotel power supply. (No other equipment had problems, but it was all relatively low power.)

But I just got back and now it wouldn't turn on at all. (The power light barely flashes green, then it turns off, and the cycle repeats.)

Fortunately, my battery backup and DC power supply appear to have no issues, so I'll be using them for a few days.

I am thinking it's likely the issue is with the power supply brick. (A new brick has been ordered from our sponsors.) I've traveled with it to many countries with no issues before this.

It is just under two years old.

So, a few questions:

Who else has had a Resmed power brick fail? About how long is their expected lifetime?

Is there any reason to believe the brick starting to fail the first night of my vacation was anything other than a coincidence? I'm thinking that it could have been starting to fail and that the extra voltage was enough to accelerate that process a little.

This power supply stuff is Greek to me. Does this thread have any possible relevance to your problem? It was an airplane power supply, not a hotel, but maybe a similar problem: viewtopic.php?f=1&t=87993&st=0&sk=t&sd=a

[JointPain]

This power supply stuff is Greek to me. Does this thread have any possible relevance to your problem? It was an airplane power supply, not a hotel, but maybe a similar problem: viewtopic.php?f=1&t=87993&st=0&sk=t&sd=a

Thanks a lot for the link, but it's a different issue.

[Drowsy Dancer]

This power supply stuff is Greek to me. Does this thread have any possible relevance to your problem? It was an airplane power supply, not a hotel, but maybe a similar problem: viewtopic.php?f=1&t=87993&st=0&sk=t&sd=a

Thanks a lot for the link, but it's a different issue.

I was afraid of that. I can practically feel my lips moving when I start to read about power issues...fuses...AC, DC....isn't that a rock band?

[billbolton]

When I first plugged my Resmed S9 Autoset into the hotel power in Amsterdam, the unit came on, then immediately went off, then on again, off again a few times before staying on. But then it would turn off semi-randomly during the night. This repeated every night and appeared to be getting worse. I assumed it was some quirk of the local / hotel power supply. (No other equipment had problems, but it was all relatively low power.)

A couple of questions.....

Did you have anything else at all plugged into the same power outlet

What sort of adapter were you using to match a European wall socket to your power plug

Cheers,

Bill

[archangle]

The most likely cause is mechanical problems cause by packing, unpacking, banging, etc. the power supply. Try wiggling all the connectors, flexing the power cord, etc. to see if you can make the problem come and go. Inspect everything by eye, especially the the connectors.

You could also have mechanical damage to the plug on the blower unit as well.

You could have had something like an overvoltage or power surge, but I would expect the power brick to be really tough in that respect.

[JointPain]

A couple of questions.....

Did you have anything else at all plugged into the same power outlet

What sort of adapter were you using to match a European wall socket to your power plug

Cheers,

Bill

Nothing else was plugged into the same power outlet, but there was a desk lamp plugged into another power point immediately above it. I think it's likely that all the outlets in the room were ultimately wired back to one circuit to the room. (All power and lights in the room were controlled from a single insert-your-room-key-here switch next to the door.)

I used a straight-forward mechanical adapter. In fact, I used two different ones on different nights to rule adapter issues out. I've previously used the same arrangement in Australia without problems.

[JointPain]

The most likely cause is mechanical problems cause by packing, unpacking, banging, etc. the power supply. Try wiggling all the connectors, flexing the power cord, etc. to see if you can make the problem come and go. Inspect everything by eye, especially the the connectors.

You could also have mechanical damage to the plug on the blower unit as well.

You could have had something like an overvoltage or power surge, but I would expect the power brick to be really tough in that respect.

Thanks, I'll look at that carefully tonight. The power cord just below where it plugs into the blower unit gets a tight bend in it, and a mechanical failure there is a strong possibility.

I did try unplugging and reconnecting everything a few times to no avail.

[chunkyfrog]

Aha! A de$ign flaw. Just what we can expect from . . (who was that again?)

[billbolton]

Nothing else was plugged into the same power outlet....

It might have just been a faulty connection "behind the wall" to that one socket.

I've previously used the same arrangement in Australia without problems.

If you mean you used the same adapters, does that mean you had the ones a variety of different pins on the plug side that can slide out to match the relevant wall socket? If so, do you know what brand they were?

While the switch mode power supplies that are incorporated in most modern CPAP power bricks are pretty tolerant of a lot of things related to the quality of mains suppled power they receive, it is possible that a large number of small power interruptions, due to a faulty connection on the supply side, could damage one

Cheers,

Bill

[StuUnderPressure]

While the switch mode power supplies that are incorporated in most modern CPAP power bricks are pretty tolerant of a lot of things related to the quality of mains suppled power they receive, it is possible that a large number of small power interruptions, due to a faulty connection on the supply side, could damage one

Cheers,

Bill

So, does the S9 AutoSet power brick act somewhat like a mini UPS?

[khauser]

While the switch mode power supplies that are incorporated in most modern CPAP power bricks are pretty tolerant of a lot of things related to the quality of mains suppled power they receive, it is possible that a large number of small power interruptions, due to a faulty connection on the supply side, could damage one

Cheers,

Bill

So, does the S9 AutoSet power brick act somewhat like a mini UPS?

Nope.

The term "Switched Mode Power Supply" references a technology that allows the power supply to work with a wide range of input voltages and frequencies. A UPS might be able to compensate for voltage brown-outs but in the case of switch mode power supplies that's hardly necessary.

An interesting point about switch mode power supplies is that they HATE stepped-approximation sine waves (how many people just pressed the close button?)

That means that if you DO use a UPS (or generator, whatever) and it doesn't have a true sine wave output, it most certainly CAN damage this kind of power supply. Unfortunately, true sine wave UPS' are more expensive.

[5thumbs]

Try checking the pins in the plug connector that attach the s9. Could be that upon inserting the plug, one of the pins was not aligned and got bent, providing intermittent power. If this is the case, you may be able to realign the pin(s) with a small tweezer. I just so happened to be at Sleepquest picking up supplies when a customer came in with a "broken power supply" and they gave him another one but showed him that the problem was with the plug.

[cosmo]

Does the power brick have a green light when plugged in? I can't look at mine at the moment. The travel S9 brick does have a green indicator if it has power.

[JointPain]

Try checking the pins in the plug connector that attach the s9. Could be that upon inserting the plug, one of the pins was not aligned and got bent, providing intermittent power. If this is the case, you may be able to realign the pin(s) with a small tweezer. I just so happened to be at Sleepquest picking up supplies when a customer came in with a "broken power supply" and they gave him another one but showed him that the problem was with the plug.

They don't appear to be bent.

Does the power brick have a green light when plugged in? I can't look at mine at the moment. The travel S9 brick does have a green indicator if it has power.

In Amsterdam, when the blower was powered up, the green light on the brick was on. When the blower lost power, the green light on the brick was out. The loss of power transition was too fast for me to say which happened first. (I could trigger a power-loss event with a good chance of success by taking a quick breath in.) Back in Houston, the green light comes on, the unit starts to power up, then it loses power and the green light goes out. A moment later the process starts over. If the power brick is not plugged into the blower, the green light stays on.

The most likely cause is mechanical problems cause by packing, unpacking, banging, etc. the power supply. Try wiggling all the connectors, flexing the power cord, etc. to see if you can make the problem come and go. Inspect everything by eye, especially the the connectors.

You could also have mechanical damage to the plug on the blower unit as well.

You could have had something like an overvoltage or power surge, but I would expect the power brick to be really tough in that respect.

Wiggling the power connectors etc. makes no difference that I can see. The unit was packed carefully inside the S9 travel bag with the hose wrapped around the power supply, and the S9 bag was packed inside my backpack, which I hand carried. I did not use the CPAP while travelling.


The new power brick has arrived from the site's sponsor (love that service - living in Houston helps). The new brick appears to be working fine.

Thanks a lot everyone for your comments and assistance.