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I ended up putting the z1 in a vise and gently squeezing the edges. It ended up coming apart on one corner and then i just forced the rest to break apart. I unscrewed 4 more screws inside and then took out the circuit board and saw the BR1225 battery. The battery is spot welded on so i ended up snipping the wire leads which attached to it. I hope to get the battery tomorrow and will try to solder it to the remaining connectors and cross my fingers.

You can do that!
Easy, peasy.

FAIL!! Installed the battery (it isnt as easy as soldering it on, because solder doesnt adhere to batteries)

Powered it up - it booted fine, no errors
Tried to turn it on, then Fault 33 code
Tried multiple times, always Fault 33 after turning it on.

SO unfortunately i still have a doorstop.

I also replaceed old BR1225(3V battery with soldering holder) to new CR2032(3V with replaceable holder).

After I turned it on and set pressure and date/time, It worked at unstable air flow.
Then I turned it off, It displayed FAULT 33 again.

I thought unstable air flow is caused by over pressure detection.
Therefore, I put off transparent thin tube connected to main board.

Finally It works fine with no FALUT code.

This device is controlled by PIC microcontroller.
I think it needs to set some parameter to EEPROM after changing battery.

E-33 ERR_NVDATA_STORAGE_ERROR •Defective EEPROM •Replace Main PCA

I have some error "Fault 33" and seems my battery also have issue. (Every time when I remove the adapter, Z1 reset the date and time.)
I tried to change the battery but I could not open the Z1 case after I removed 5 screws.
So I give up it.
Then I removed plastic pipe in intake port.
It has hole though I don't know the correct position after I remove it.
But I tried to power on Z1 without this pipe.
Then my Z1 work without Fault 33.
I think the pipe position is the one of reason to change the pressure rate and cause Fault 33.

Disassembly.

Observe static discharge precautions.

Remove the five screws. Note lengths and locations. The two short screws go on the narrow end below the manufacturer's label.

Using a spudger, or guitar pic, pry around the seam. Gently get the gap wider and wider. There are no adhesives or tabs that need to be pushed in. Just be patient with slow, steady pressure.

After you get the seam separated, but before the case comes apart, two things have to happen:

1) The silicon collar for the air output needs to be pushed into the body. When reassembling, use a small, dull rod in the smaller hole to force the collar back into the proper location.

2) The tube from the filter assembly through the lower case needs to be pulled out. Note the angle of rotation of the tube before you remove it. Maybe mark it with some tape or a marker. When the case gets reassembled, the tube is inserted through a hole in the outside of the lower case but the inner end goes through a hole in a divider on the upper case. Mostly assemble the two halves of the case then insert the tube through the opening on the lower case. While peaking through the gap between the cases, be sure that the tube goes into the opening in internal divider of the upper case.

All of the rest of the disassembly is self evident.

Hey guys,

thanks for the advice with the battery.

I also replaced the BR1225 with a CR2032. I used a CMOS battery, because it is already wired and a CR2032 has much more capacity so it should work for a couple of years.

However first it seemed that it works but unfortunately it doesn't. Still got Fault 33 a lot of times. If I get it running the turbine is stuttering.
My device is currently half assembled so I took the chance to try serveral things out but that did not lead anywhere.
Seems for me like I also have a doorstop.

Any advice is very welcome if not I may look forward ordering a new one in the future.
Are newer versions any better?

Doorstop here, too. Worked perfectly fine prior to the pandemic, and received the same fault codes during my first overnight travel. Contacted HDM and received a “no longer in warranty, parts unavailable” reply along with an option to buy a refurbished Z2 for $195 w/a 6-month warranty. Purchased mine in 2015 so it seems there is a 5-year shelf life as others have experienced. Won’t buy any HDM products again.

I have made some progress. Because the motor was hunting, I guessed that the pressure switch was faulty. If i removed the tube, the motor could start and run for a time. I opened the machine and found the pressure switch. As the machine didn't work, I had nothing to lose and poked a soft wire in the pressure sensor hole. The machine now runs fine and the Fault 33 error has disappeared. The only problem is that I need to replace the faulty sensor and I can't find one online, though I can see similar ones. Are there any electronic engineers who can tell us where to buy them?
I attach a photo I took of the part. It is part number MPXV5000G. The nearest I can find is part number MPXV5010G. Does anyone know if this will do?

My Z1 just died with a fault 33. Stuck traveling for a week with no cpap. This is not a good way to treat customers who depend on cpap for quality of life. Seems like HDM should be required to let us know the machine has an expiration date!!!!

So I’m in the same boat. First night of a week long trip and just found out my Z1 is bricked. Bought this in 2015 and only used it a handful of times, always without problem. Code 33 from what I read here is not user serviceable. Even though it is 7 years old, based on my use I sure didn’t get my money’s worth out of this unit. I’m loathe to give HDM any move of my money as this seems to be a design issue, possibly built-in obsolescence.

Any recommendations on a replacement travel machine?

AndrewM wrote: ↑

Sun May 01, 2022 12:59 pm

I have made some progress. Because the motor was hunting, I guessed that the pressure switch was faulty. If i removed the tube, the motor could start and run for a time. I opened the machine and found the pressure switch. As the machine didn't work, I had nothing to lose and poked a soft wire in the pressure sensor hole. The machine now runs fine and the Fault 33 error has disappeared. The only problem is that I need to replace the faulty sensor and I can't find one online, though I can see similar ones. Are there any electronic engineers who can tell us where to buy them?
I attach a photo I took of the part. It is part number MPXV5000G. The nearest I can find is part number MPXV5010G. Does anyone know if this will do?

My Z1 was made in 2015 and it has the part number MPXV5004G. The one online place I could find that is selling for quantity of one at more reasonable price is Digi-Key:
https://www.digikey.com/en/products/det ... W_EALw_wcB

I opened my Z1 and replaced the battery, but still getting Fault 33. I may just buying a new unit, probably Airsense Mini instead of attempting to fix my Z1.

I have a similar experience with the Fault 33 on my seldom used Z1 CPAP. Purchased in 2015, I've used it on short trips when I haven't wanted to haul my larger one along, probably two dozen times at most. Given the posts on the CMOS battery, I replaced the board soldered button battery (reading 2.2v when I removed) with a CR2032 battery holder and confirmed 3v to the board power locations where I soldered it in. After powering up and applying a firmware update and updating the date and time, I worked through Fault 21 to set the pressure.

After all this, the fan on the unit spins up for a moment, then reports Fault 33. While a low CMOS battery seems a common culprit on this thread, It seems another failure like the pressure sensor may be the cause, and soldering that one is likely a bit too delicate soldering... so a pretty expensive brick.

If anyone has any other ideas for easier resolution to the Fault 33, I appreciate the input.

I was surprised to see this comment someone made earlier here:
"Contacted HDM and received a “no longer in warranty, parts unavailable” reply along with an option to buy a refurbished Z2 for $195 w/a 6-month warranty. "
When I contacted them today, they quoted a price of $295 for a Z2Auto!!!! Maybe the price difference is for the "auto" function, FWIW.