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[How to] Fix Your Own Noisy CPAP - Don't discard old CPAP with worn bearings
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SuperSleeper Offline


Posts: 9,885
Joined: Feb 2012

Machine: PR System One REMstar Auto (DS560)
Mask Type: Nasal pillows
Mask Make & Model: ResMed Mirage Swift II
Humidifier: none
CPAP Pressure: 12.5 - 18.5 cmH20 (auto range)
CPAP Software: SleepyHead

Other Comments: Have diabetes Type II

Sex: Male
Location: Illinois, USA

Post: #1
Fix Your Own Noisy CPAP - Don't discard old CPAP with worn bearings
[copied from old forum]

RonInRochester Wrote:I retrieved this aged CPAP from my father in law who has insurance and replaced it because it had become excessively loud. My son had a sleep study and Rx when he was employed. Layed off and uninsured he could not afford to buy a CPAP. I would have ponied up the $$ as he really does need the machine however this "rebuilt" one has done the trick.

Hope you can find some incentive to repair rather than replace if you need to. CPAPs are similar to computers in that it's often not their electronics that fail, it's the mechanical parts in their hard drive or fan in the case of the CPAP.

1st and foremost I assume no responsibility for any damage to yourself or your equipment, I am not a professional repair person. My only interest is sharing what follows is to possibly help you repair your own CPAP(s) for your personal use -- RonInRochester.

In about 1 hour successfully replaced the 2 fan motor bearing in an aged, ready for discard, "ResMed CPAP S6 Lightweight" branded as manufacturer = Sullivan. It was unacceptably noisy but the fan motor had not seized. No specialized tools were required and the bearings needed appear to be a commonly available standard size. The specific process may or may not apply to other ResMed or other manufacturers' CPAPs. Use this a a general guideline for others, it is specific to the "ResMed CPAP S6 Lightweight".

1. Using a standard US allen wrench remove the machine screws located on the underside of the unit. The top cover lifts off easily.

2. Lift out the simple circuit board unplugging the ribbon cable that goes to the LED display, the 2 pin connector and the 6 or 8 pin connector. This board is primitive by 2011 standards and therefore easy to work with but handle gently to avoid dislodging and of the soldered on components.

3. Remove the hard plastic fan box cover and other obvious parts.

4. Remove the fan housing which is contained in a rubber vibration dampening mount. You will be left with a small squirrel cage fan enclosed in a clear plastic clam shell housing which has to be opened to gain access to the fan and motor proper.

The clear plastic enclosure is in two clam shell like halves. The task is to open the enclosure and in order to remove the fan motor with attached impeller. The halves twist together and are secured with about 6 integrel molded in "clicker teeth" best described as similar to the mechanism used to snap shut common nylon wire ties, a "one way" insertion and clicking against a row of teeth from the bar. "Authorized" service centers no doubt have a special tool to open the enclosure --- not needed.

My solution: using a tiny rotary rasp bit in a Dremel Tool, I simply milled away the "teeth". Afterward the enclosure twisted open easily. Aware that the closure mechanism was irrevocably altered the plan was to glue the halves back together.

Pleasantly, no glue was required when reassembled as the altered halves stayed securely locked together.

6. Next task was to press the fan motor shaft out of the motor housing. With little effort if made a puller plate from a 2: OD, 7/8" ID flat washer (see photo). Drilled 4 small holes in the washer and screwed the washer to the motor housing using the screws that had held the housing to the plastic clam shell. Next I used a "garden variety" 2 arm puller with the arms on the perimeter of the flat washer and the center bolt on the motor shaft. Pleasantly with minimal screw force on the center bolt, the motor housing parted from the armature exposing the two small sealed ball bearings that were worn. Gently tapping with a soft wooden chop stick both bearings came free from the housing and were in my hand.

7. Next part is true however it's unlikely that you will be this fortunate. <-- very very dumb lucky --> I had ~ 15 of exactly the correct size replacement bearing in my workshop. I don't have even a small collection of other bearings. These were retrieved from "throwout" bin where I had worked about 20 years ago. These exact fit bearing are in the photo, markings are "CANADA FAG R3Z" and are nominally 13 mm OD and 6 mm ID. They slip precisely into the fan motor housing, no need for a "press fit". Check online or local bearing distributors and buy the ones you need for your specific CPAP.

8. Reassemble and plug it in.

[Image: Bearings_and_Flat.jpg]
02-28-2012 04:56 PM
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