Firmware 2.2.0 will cause digital board fuse to blow on PWD II


#1

I have an original PWD II and decided to try to listen to firmware 2.2.0. I loaded 2.2.0 up and it appeared to be fine. I turned the Unit off, removed the SD card and restarted. Instantly the DAC looked dead. Nothing lit up. I popped the top off and checked continuity of the fuse and the digital board fuse was blown. I replaced the fuse and the same thing happened, it started once but when turned off and restarted it blew the Digital fuse board instantly again.

I replaced the fuse again, inserted a SD card with Firmware 2.4.6 and restarted. It loaded initailized and worked fine. I turned the unit off and restarted, no problem. Did this a third time (cycled off/on) and again no problem.

Known issue?

PWD II (original not upgraded), no bridge, running MacBook Pro into PWD II with USB, PWD II plugged into dedicated Bryston BIT-15 balanced power conditioner.

Glass fuse sounds more extended, crystalline but perhaps a bit more lean and “Hi-fi” sounding when compared to the original fuse that came with the PWD II.


#2

Don’t think I’ve ever heard that one before. Very strange.


#3

My PWD II has been working perfectly again for the last 4-5 hours with firmware 2.4.6. It has been cycled on/off a half dozen times or so and no issues. I agree, this issue with firmware 2.2.0 is very odd. I can only guess that some setting in 2.2.0 was causing start up digital current draw to exceed the fuse’s limits? I am pretty relieved, was not happy when I thought I had a $4k paperweight. I figured I would post this here since someone, somewhere will probably face the same scenario.


#4

I have never heard of that either and am questioning whether it’s even true.


#5

There has got to be something else going on.


#6
Paul McGowan said I have never heard of that either and am questioning whether it's even true.
Wow Paul. Some customer service, yea I just made this up. I guess I should have taken video of the fuses blowing (makes a nice bright flash) when I powered up the PWD II for the second time with 2.2.0 with the cover off. You just lost a customer and I'll make sure to pass on your exact response at my local audio meet to later this afternoon and in the future.

I posted this up because I thought someone else might have a similar issue and it would be helpful to know there is an easy fix. But based on your response, I am sure this thread will conveniently disappear shortly.


#7

Nice overreaction tubedriver! I think Paul’s choice of words may not have been the best but I’m pretty sure he wasn’t saying the fuse blowing was false or made up. What he was saying is it wasn’t the result of the firmware upgrade. The point being with all the variations and loadings of firmware they have never seen it lead to a fuse blowing. While it can’t absolutely be eliminated, it is highly unlikely. Perhaps in the process of putting the card in and out you nudged something? How about disconnecting everything from the DAC and try reloading 2.2.0 and see what happens.


#8

Yes and PSA is one of the best in customer support so I’m sure if you give them a chance they’l help you figure it out.


#9

Correct fuse values? Maybe defective fuses?


#10
tubedriver said
Paul McGowan said I have never heard of that either and am questioning whether it's even true.

Wow Paul. Some customer service, yea I just made this up. I guess I should have taken video of the fuses blowing (makes a nice bright flash) when I powered up the PWD II for the second time with 2.2.0 with the cover off. You just lost a customer and I’ll make sure to pass on your exact response at my local audio meet to later this afternoon and in the future.

I posted this up because I thought someone else might have a similar issue and it would be helpful to know there is an easy fix. But based on your response, I am sure this thread will conveniently disappear shortly.


I am sorry, I didn’t mean to imply you made it up. I am sure the fuse must have blown - and I am sorry if I came across as questioning that. I wasn’t.

I have just never heard of firmware doing something like that and knowing the firmware has nothing to do with controlling the amount of inrush current, I would still suggest it was not the fault of the firmware.

Having said that, there’s obviously something going on and we’d be happy to take a look for you.

But firmware? That’s still a new one on me.


#11
Paul, I apologize for snipping back at you, I had not finished my morning coffee yet and misread your intent. I understand your position that the firmware should have nothing to do with inrush current. It has been over 24 hours since I last reflashed back to 2.4.6 and my PWD is functioning perfectly. I have one possible longshot suggestion. I purchased my PWD new and have used it daily for several years, it is always on. Perhaps the original fuse became compromised over time and it was enough that the inrush current just blew it during that reflash to 2.2.0? Here is where it gets improbable but not impossible, I went down to my work shop and fished around in a misc fuse tray and only had one old fuse (that looked intact). It blew too. Perhaps it was also compromised/used? I then switched the orginal HiFi analogue board fuse over to the digital board side and temporarly place a 5A fuse (smallest value I had left) on the analogue board side. I know, I know...never use a higher value fuse but the analogue board appeared to be operating fine. I reinserted the SD card containing 2.4.6, held my breath and turned on the PWD II. No problem, it reflashed and has been running perfectly. I just got a knock on the door from Amazon (amazing how fast stuff is delivered) and got 10 new 1A, slowblo, 250V fuses so I will just replace both and button everything back up. I should now reflash back to 2.2.0 to confirm if that was just some improbable fuse situation but I am loath to mess around when it appears to be working fine. And in general, I am prety happy with the sound as is.
photo image_zpspzrqf1jt.jpeg
Paul McGowan said
tubedriver said
Paul McGowan said I have never heard of that either and am questioning whether it's even true.
Wow Paul. Some customer service, yea I just made this up. I guess I should have taken video of the fuses blowing (makes a nice bright flash) when I powered up the PWD II for the second time with 2.2.0 with the cover off. You just lost a customer and I'll make sure to pass on your exact response at my local audio meet to later this afternoon and in the future.

I posted this up because I thought someone else might have a similar issue and it would be helpful to know there is an easy fix. But based on your response, I am sure this thread will conveniently disappear shortly.

I am sorry, I didn't mean to imply you made it up. I am sure the fuse must have blown - and I am sorry if I came across as questioning that. I wasn't.

I have just never heard of firmware doing something like that and knowing the firmware has nothing to do with controlling the amount of inrush current, I would still suggest it was not the fault of the firmware.

Having said that, there’s obviously something going on and we’d be happy to take a look for you.

But firmware? That’s still a new one on me.

I
Paul McGowan said
tubedriver said
Paul McGowan said I have never heard of that either and am questioning whether it's even true.
Wow Paul. Some customer service, yea I just made this up. I guess I should have taken video of the fuses blowing (makes a nice bright flash) when I powered up the PWD II for the second time with 2.2.0 with the cover off. You just lost a customer and I'll make sure to pass on your exact response at my local audio meet to later this afternoon and in the future.

I posted this up because I thought someone else might have a similar issue and it would be helpful to know there is an easy fix. But based on your response, I am sure this thread will conveniently disappear shortly.

I am sorry, I didn't mean to imply you made it up. I am sure the fuse must have blown - and I am sorry if I came across as questioning that. I wasn't.

I have just never heard of firmware doing something like that and knowing the firmware has nothing to do with controlling the amount of inrush current, I would still suggest it was not the fault of the firmware.

Having said that, there’s obviously something going on and we’d be happy to take a look for you.

But firmware? That’s still a new one on me.


#12
tubedriver said

I posted this up because I thought someone else might have a similar issue and it would be helpful to know there is an easy fix. But based on your response, I am sure this thread will conveniently disappear shortly.


Nope. The good, bad and ugly all remain. PS Audio is all about customer service and resolving issues in an open, transparent way.

It appears you have solved the problem by getting fresh fuses. While I never thought of a fuse aging, this is more likely than firmware blowing a fuse. The whole issue remains very weird.


#13

No worries, and after rereading my response I was the one wrong. Sorry. It did sound as if I were questioning your words.

It makes little sense the old fuses had become stressed - especially since you keep the unit turned on from the rear panel all the time. It’s troubling this happened.

Let me know how it goes with the new fuses. We’re happy to have a look for you.


#14

Just popped in two fresh fuses, and restarted. It seemed to hang for longer than usual at startup, I turned it off and restarted and it appears to be working fine. Overall, I have never had any issues with this DAC at all (no noises, dropouts, clicks (other than normal relay stuff) or screen issues etc), it has been problem free. I’ll let you know if it develops any issues but it seems fine as of now. Thanks.


#15

If nothing else, it got me to clean off the dust on the top of my PWD. I don’t want to get hairline scratches in the piano finish of the top plate so it usually gets neglected when I dust the system. But it (and my whole system) was way overdo, I put a bit of wax on the top plate. I forgot how nice it looks when clean.

photo image_zpsl5e8fvus.jpeg


#16

Ok, this will hopefully close this issue. Now that I have 10 new fuses, I reformatted the SD card, downloaded and reloaded FW 2.2.0 for a second time and tried again. It loaded (upper left hand small blue logo blinked for about 45 seconds), then slowly initialized, finished initializing, unit went dark then it initalized again (this time much faster). I played music for 30 minutes or so. Sounded fine. I popped the SD card out. I took a video of the of the next on/off cycle just in case it died again. I turned it off, waited 30 seconds, turned it on and it very quickly initialized and plays fine. I did this a couple times and no issues. So it appears (at least based on couple few observations) that it must have been some weird issue with the fuses and NOT with FW 2.2.0. I originally jumped to the wrong conclussion.

I am listening to 2.2.0 and it sounds subtly different. I have trouble picking out specific differences but my impression is that 2.2.0 is smoother, more “analogue” sounding with an overall presentation that seems to emphasize mids down to bass. I seem to focus more on bass lines and vocals. From memory, 2.4.6 had more overall detail, air, spatial resolution, trailing edge harmonic type stuff but sounds perhaps a bit more Digital? But these differences are slight and this is more an overall impression since effort involved in swapping firmware makes it difficult to do a quick comparison.


#17

Glad it worked out. Sounds like the fuses blowing were just coincidences (two in a row can easily be construed as causation, even when it’s not). Remember to put the card back in if you use the Bridge (1 or 2) and want album art. You can erase it to get rid of the firmware files (or put them in a folder) but they shouldn’t try to load again anyway.