request: resmed s8 (any version) teardown/disassembly

tungpust · Post by **tungpust** » Wed Apr 02, 2014 4:58 am

Can anyone help with some teardown/disassembly instructions and photos for a resmed s8 (any model, but I have the autosetII)? I'm trying somewhat desperately to repair it, as it is out of warranty and in good condition apart form a recent accident.

Background: I overfilled the humidifier tank, got some water backsplash, presumably during EPR pressrure relief (3cm), and although the machine worked through the night it refused to start again the next evening, and gave me the dreaded "System Err 1019/Call service" message on the LCD.

Actions: I lightly warmed the cpap overnight on top of my desktop pc to get humdity out, but the machine still would not run, except late last night it would run for 3 seconds and then give a "System Err 1015" (different from 1019). I suspect that the flow meter is stuck and the motor/fan/pump control thinks the tube is blocked, hence shuts off. I gleaned this info about error 1015/1019 via google.

Moreover, I acquired a Torx T10 screwdriver and attempted to disassemble the machine with the intent of drying the innards and see if I could locate a stuck flow meter/transducer. Screws did not come all the way out, but they may nevertheless be sufficiently unfastened. However, I am not able to pry the two halves of the cpap clamshell exterior apart. Especially around the air exit tube, the clamshell seems to be stuck very solidly. Other places I can make a small crack but I cannot get the halves apart. I tried to find the location of locking/snap tabs with a thin and dull letter opener (knife). No luck so far.

References: I looked at the very nice s9 teardown post/photos, but the s9 is sufficiently different from the s8 that I was not able to deduce how to crack open the s8.

tungpust · Post by **tungpust** » Wed Apr 02, 2014 12:39 pm

I am having some luck disassembling the machine now. I have found that the airflow sensor is a Honeywell AWM 730B5 (B5 not 85, CORRECTED). It is visible from the underside, next to the the fan motor. It appears that it is part of a side path of the main air path.

I have also found another sensor that is located on the main circuit board and marked GE 1210 CO2020 9197 DJOC. This part number I cannot find on the web. The sensor is connect via a transparent, flexible 4mm (outer diameter) plastic tube that is connected at one end to a small hole through the wall of the main air path output pipe (i.e. where the cpap main hose is attached). At the other end, the tube terminates at the underside of the circuit board and appears to feed into the aforementioned sensor on the PCB. Update: This part appears to be a humidity sensor, it looks like this one, roughly: GE CC2A35 , http://www.mouser.com/search/refine.asp ... =149204143

I will try to post more info and some photos as I make progress.

Right now I am drying the innards of the cpap with a hair dryer set to low heat, and in particular I am drying several wet pieces of gray foam.

prion · Post by **prion** » Wed Apr 02, 2014 12:58 pm

Someone gave me an S8 with exactly the same troubles. He said it sucked up some water from the humidifier. I disassembled and dried it out with a hair dryer
but never got it to work. I too wondered about the two components. The first I could get from Mouser. At the time the other one didn't cross over so I gave up.
You might try Mouser again this was a year ago when I started thinking about CPAP. I never did fix the S8 as I found an S9 cheap on CL

tungpust · Post by **tungpust** » Wed Apr 02, 2014 1:43 pm

Thanks for posting prion. I had also found a GE part that looks like the one in the s8, see the link in update above. Interesting to hear that drying did not help in your case. I wonder if there is a hidden reset button somewhere, or a reset via external cable or an internal JTAG header.

I am done with drying etc and ready to assemble again to see if it will work. Having trouble connecting the PCB to the connector that is in the northwest(*) corner of the PCB, close to airpath exit, the connectorwith 4+5 pins. It is tricky to get the alignment right so that all pins will glide in.

(*) northwest/11am when orienting the machine so that the display is on normal reading position.

prion · Post by **prion** » Wed Apr 02, 2014 4:06 pm

I had that problem as well with the "nested" header. I did get the unit back together after fiddling with it for a couple hours. It threw the same error.
I had fun messing with it but never got it to work. I think I saved it in the garage somewhere but since we had the same error code I doubt any
part I have will do you any good.

prion · Post by **prion** » Wed Apr 02, 2014 4:14 pm

I also couldn't find a reset. I used to jtag sat. IRDs so I have all the stuff, however no software to interface with this device. I agree it's the flow sensor or the other
part. I looked all over for schematic to no avail. Water shorted something. It could be an IC, or something simple. I have desoldering setup so no problem replacing
parts, if only we knew which one is faulty. If you figure it out, I just hope I saved the unit.

echo · Post by **echo** » Wed Apr 02, 2014 5:15 pm

How easy was it to find a Torx screwdriver? I need a small diameter one to take apart my broken 420Es in the hopes I can make 1 good one from the 2 dead ones. I got stuck at unscrewing them open and haven't made it to the hw store yet. My partner said it would be difficult to find.

apw5746 · Post by **apw5746** » Wed Apr 02, 2014 5:40 pm

tungpust wrote:Can anyone help with some teardown/disassembly instructions and photos for a resmed s8 (any model, but I have the autosetII)? I'm trying somewhat desperately to repair it, as it is out of warranty and in good condition apart form a recent accident.

Background: I overfilled the humidifier tank, got some water backsplash, presumably during EPR pressrure relief (3cm), and although the machine worked through the night it refused to start again the next evening, and gave me the dreaded "System Err 1019/Call service" message on the LCD.

Actions: I lightly warmed the cpap overnight on top of my desktop pc to get humdity out, but the machine still would not run, except late last night it would run for 3 seconds and then give a "System Err 1015" (different from 1019). I suspect that the flow meter is stuck and the motor/fan/pump control thinks the tube is blocked, hence shuts off. I gleaned this info about error 1015/1019 via google.

Moreover, I acquired a Torx T10 screwdriver and attempted to disassemble the machine with the intent of drying the innards and see if I could locate a stuck flow meter/transducer. Screws did not come all the way out, but they may nevertheless be sufficiently unfastened. However, I am not able to pry the two halves of the cpap clamshell exterior apart. Especially around the air exit tube, the clamshell seems to be stuck very solidly. Other places I can make a small crack nut I cannot get the halves apart. I tried to find the location of locking/snap tabs with a thin and dull letter opener (knife). No luck so far.

References: I looked at the very nice s9 teardown post/photos, but the s9 is sufficiently different from the s8 that I was not able to deduce how to crack open the s8.

check this out. especially the post by Jackie999. might mean something to you.

http://s7.zetaboards.com/Apnea_Board/topic/8489216/1/

tungpust · Post by **tungpust** » Thu Apr 03, 2014 10:39 am

echo wrote:How easy was it to find a Torx screwdriver? I need a small diameter one to take apart my broken 420Es in the hopes I can make 1 good one from the 2 dead ones. I got stuck at unscrewing them open and haven't made it to the hw store yet. My partner said it would be difficult to find.

Any halfway decent hardware store should have it. I got my T10 Torx at Sears for $3.99. Good luck with the repair.

tungpust · Post by **tungpust** » Thu Apr 03, 2014 10:41 am

prion wrote:I also couldn't find a reset. I used to jtag sat. IRDs so I have all the stuff, however no software to interface with this device. I agree it's the flow sensor or the other
part. I looked all over for schematic to no avail. Water shorted something. It could be an IC, or something simple. I have desoldering setup so no problem replacing
parts, if only we knew which one is faulty. If you figure it out, I just hope I saved the unit.

Wow prion, you have a schematic for the S8? I would love to see that! Please look at my next post for status update.

tungpust · Post by **tungpust** » Thu Apr 03, 2014 10:57 am

Time for a status update: A friend helped me get the tricky contact seated, and I reassembled the machine enough to test it. I am still getting "System Err 1019", just like Prion was saying happened to him, even after drying all the internals of the machine.

Then we tried to short out the "CMOS battery" (the name is by PC motherboard analogy) to see if that would clear the error. Wall power should be unplugged, of course. The CMOS battery is underneath the LCD display and the terminals can be accessed from the two sides. This "reset" caused a longer boot time, maybe 30sec before the machine would light up the LCD screen. Probably the machine reloaded some firmware from flash, or some such. But I still get "System Err 1019". So I got as far as Prion described in his posting.

At this point it is hard to tell whether the airflow sensor is truly broken, or the problem is just that an error code need to be cleared. Ideas are welcome. One thought I have is to look for a data cable of the type used at the doctor's office, and maybe some diagnostic software. Who knows where I might be able to get that.

By the way, I see on mouser that one can get replacement airflow sensors AWM730B5 for $192.55 in quantities of 1, but that is very expensive and a big gamble since I do not know whether it is really the airflow sensor that is broken. The AWM is located fairly high in the chassis so I don't see why it would get wet, nor why it would be ruined by a splash of water.

http://www.mouser.com/ProductDetail/Honeywell/AWM730B5
http://www.mouser.com/ds/2/187/awm730b5-253376.pdf

Also: I have taken quite a few photos that I will upload or link up later, but right now I have to concentrate on the repair.

prion · Post by **prion** » Thu Apr 03, 2014 12:27 pm

Hey that was a good idea pulling that battery to clear the code. I saw the battery and never even crossed my mind to try that although I do it
on computers all the time. Too bad it didn't work. I don't have a schematic and really tried to find one.

Sir NoddinOff · Post by **Sir NoddinOff** » Thu Apr 03, 2014 12:41 pm

This may or may not be of interest to you, but others may benefit. Check this thread for the teardown of an S9. It's not an S8 but does talk about the clips at the back of the case and some tricks to get that to reassemble correctly.

viewtopic/t96624/Resmed-S9-Elite-Teardo ... tures.html

eillib · Post by **eillib** » Thu Apr 03, 2014 2:30 pm

I would have tried the old cellphone trick of putting it in a bag of rice or in a plastic bag with the a can of moisture remover (used in basements and closets) for a couple of days. Using a hair dryer can force the water deeper into the machine.

tungpust · Post by **tungpust** » Thu Apr 03, 2014 4:33 pm

eillib wrote:I would have tried the old cellphone trick of putting it in a bag of rice or in a plastic bag with the a can of moisture remover (used in basements and closets) for a couple of days. Using a hair dryer can force the water deeper into the machine.

Generally speaking that is a good idea, but in my case I already have the CPAP completely taken apart and each part dried individually. The fact that the error message will not go away is the main mystery.

request: resmed s8 (any version) teardown/disassembly

request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

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Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly

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Re: request: resmed s8 (any version) teardown/disassembly

Re: request: resmed s8 (any version) teardown/disassembly