malfunction Respironics M Series External Power Supply

just wondering is there anyone had experienced the Respironics M series external power supply (power adapter) failure? I brought the M machine a couple of months ago and recently the machine did not work, I tried to figure out what's wrong and I used another adaptor(same series) and the machine back to life, therefore, i swapped the malfunction adaptor and connected it to another M machine and found that the machine did not work. So, I wrote to CPAP and they asked me to return the adaptor for checking and I've just received their email saying that after they checked and used it with another M machine for 18 hours and it work ok. They now ask me to pay the shipping cost us$75 and send the adaptor back to me (i'm in HK). but i'm not convinced cause this malfunction adaptor really not stable and if it does not work after they send back to HK, should I send it to CPAP again! I asked them for a replacement but they insist to send me back the malfunction adaptor but I really lost confident in CPAP!!

no, I do not have that experience yet. But $75 for an adapter is way too much when you can buy a second hand M series complete for $220 complete with humidifier.

is there no local respironics office in hongkong? Why do you have to send the power supply to US?

US$75 seems awfully high to mail a power adapter. I have had a similar weight laptop power supply mailed from HK to the US for about US$5.

gary it's not clear to me if you ever checked to make sure the wire that can come loose from the brick was securely pushed in?

To cpapernewbie: to be frank, it's much cheaper to purchase online than purchase in HK. And because i purchased it in cpap website so i need to send it back to the state.
To GumbyCT: yes, checked. My mum and I are using the same M series machine, it's my mum's unit that has problem. So, I checked everything and thought that it's the machine failure but when i swap the power supply with mine and the machine came back to life. And then i tried to use my mum's power supply in my machine and mine's failed. Therefore, I pretty sure it's the power supply problem.