Fix: Respironics System One (50 series) Humidifier Problems

I want to start out by saying if you try this fix yourself do it at your own risk and I do not guarantee it will fix your machine or if it is even safe to do. Only try this if you are good with soldering electronics.

I have 2 Respironics System One (50 series) that the Humidifiers quit working the same way. At first they seemed to not use as much water and eventually the humidifier light started flashing and the humidifiers didn't work at all. I took them to my local medical equipment supplier and they tested them and said my humidifiers were just fine and that my CPAP machines were not communicating with the humidifiers and that they could fix them for $360 each. Since my second one quit working the same way the first one did and they are both out of warranty I decided to take my older one apart to see if I could figure out what was wrong. As soon as I opened it up I could see the problem and I was able to successfully fix both of them using the method below (please forgive the fact that I repaired them on my poker table lol).

Here's the machine I have:


Take the cover off by doing the following two steps:

Pull the knob off (just pull strait up and it will come off):


Use a torx 15 screwdriver to take the two screws out of the bottom:


If you have the same problem I did you will see the problem right away. Look for the burn in the white plug red wire:


You will need to pry the white plug off because it is melted onto the prong. Here's what the prong looked like on both of my machines:


My theory is that the connection gets corroded and the less contact area the plug has the hotter it gets until it eventually burns the plug and there is no connection left. So I used sandpaper to clean the prong and I used a pair of wire cutters to cut off the burnt end of the white plug and then I cleaned the end of the red wire and soldered it directly to the prong.

Here's what my machines look like after I was done:


Here are the tools I used (I had the soldering iron set at 3 because I didn't want to get it to hot and burn up anything on the circuit board):



Again if you try this do it at your own risk and don't blame me if anything goes wrong.

How long did you have these machines before the wire burned?

Could you tell how the moisture got in there?

awesome fix for a design flaw!

They each lasted about 2 years and insurance wouldn't buy me a new machine so I paid out of pocket for the second one which was out of warranty when it broke earlier this week. I really do think this is a factory defect and I'm sure they know, but they can get people to pay to fix them without question so why admit the problem.

I'm having the same issue--humidifier isn't working. They gave me a new humidifier and it doesn't work either. I have no patience to work with Crapria on this, but I'm not handy enough to fix my own like that.

Good fix. Some anti oxidation fluid on the connectors at the time of assembly might have prevented the increased resistance, and thus the heat. Sadly, most manufactures don't think past the end of the warranty date, others design the product to fail during a specific time period. After all they do like to sell new machines.

Janknitz wrote:I'm having the same issue--humidifier isn't working. They gave me a new humidifier and it doesn't work either. I have no patience to work with Crapria on this, but I'm not handy enough to fix my own like that.

ask around, some of your friends might be handy with a soldering iron... the PRS1s are really easy to pop open...

I'm totally impressed by your discovery, not to mention the GREAT documentation which is certainly of engineering quality. Many thanks because I'm sure I'll confront this problem on one of my PR machines somewhere down the road. <loud and prolonged clapping> Shame on PR for not envisioning this failure, and double shame for not informing their distributors/DMEs.

That's a great fix you did, the only thing that I could add is to put a piece of shrink tubing over your solider connection.

Thanks so much for your post.
My Respironics 960 just recently developed the same symptoms.
I called Accurate Biomed Services for a possible repair and they are familiar with this problem.
Since my machine is stiil under warranty, they suggested sending it in and they will handle the warranty.
Since the turnaround will be about four weeks, I ordered a new machine.

The DME is shipping next day air at no extra charge, including an Oracle mask, also at no charge and discounting an additional 10%.

Ha ha ha...the secret is out. $360 to fix a bad connection. Gotta love that.

My old Remstar unit was also pretty easy to take apart and fix. These boxes are not exactly nuclear warheads.

Thank you so much for this original post.
As I mentioned before, Accurate Biosystems handles this type of repair.
I sent my Respironics 960 ASV machine to them after experiencing similar symptoms.
They have requested a new replacement from Respironics as mine was still under warranty.

They are great folks. The only cost was my shipping to them and the shipping cost to get it back to me.

I applaud your handyman skills. One tip if I may offer it to future fixers of this problem: That solder joint looks a bit "cold". If you are worried about overheating, try clamping a tiny pair of ViceGrip pliers on just past the solder point. They will stop the heat from going on down that wire so you can heat the joint till the solder flows completely.

Just got notified by Accurate Biomed Services that Respironics is replacing my 960P at no charge.
What a great company!!!

Suenyo wrote:I applaud your handyman skills. One tip if I may offer it to future fixers of this problem: That solder joint looks a bit "cold". If you are worried about overheating, try clamping a tiny pair of ViceGrip pliers on just past the solder point. They will stop the heat from going on down that wire so you can heat the joint till the solder flows completely.

Thanks Suenyo, that's a great tip for dissipating heat during soldering. I learned that trick back in high school but somehow forgot it along the many years since then. I used to use a hemostat, the same kind pot smokers use for roaches. Somewhat easier to fit in tight spaces.