X-PSU V3 Kaput, Dilemma, Pics, Solns &Improvements

[XTRProf]

Hi all,

I'm new here and will like to take this time to say hi to all. I was googling for MF interest forums and happen to find this forum which has a very high understanding and knowledge of all things MF X series and joined.

Recently, about 1.5 months ago, I bought used X-Dac V3, X-10 V3 and X-PSU V3. All were connected, except the X-10, and all was well until about 2 weeks after the purchased the whole system went just kaput with some burning smell. The system was playing for about 2 hours when it just suddenly went off with a noted burning smell and my house trip circuit tripped. Luckily, it did not affect any lighting circuits as it was night time then and the whole house would be plummeted into total darkness if was. So I investigated after resetting the trip circuit after offing the MF system.

In my investigation, I traced the problem to the X-PSU having shorted as I could smell something burning when I sniff the casing. This was confirmed when I opened up the casing and the smell is now heavy. The funny thing is when I looked at the internals, there was not a trace of fuse in the primary and secondary windings. Wow, how can that be and I was told in the manual to leave the whole system on indefinitely for the best sound. If I was to follow that, the house could have been burn down if no one was at home and the trip circuitry didn't trip.

So now my dilemma is how can I get a toroidal the same as the MF with 4 primary windings of 12-0-12 VAC without contacting MF. I wanted to service it myself to save on cost. Anyway, I tried to contact MF thru fax [phone] (ya, stupid as there was no email at their site) without any success. Also, what are the chances that the toriodal short was just caused by a bad transformer and not the X-dac having problem that caused the short? I'm not sure now as I don't have any PS to power up the X-dac now. What are the recommended fuse rating (slow or fast blow) for the secondary and primary windings if I'm to modify the thing for better safety. Safety is utmost than sound for my preference. Or is there any other ways of doing things.

All help in this area will be welcomed. Thanks all for your assistance in this dilemma.

[Deleted]

XTRProf
Why don't you just puchase a cheap 12-0-12 VAC 500mA (or 1 Amp) wallwart to check your X-DAC with ? I doubt very much that you will be able to buy another toroidal transformer with
4 x 12-0-12VAC windings, except through MF.
SandyK

[XTRProf]

sandyk said:

XTRProf
Why don't you just puchase a cheap 12-0-12 VAC 500mA (or 1 Amp) wallwart to check your X-DAC with ? I doubt very much that you will be able to buy another toroidal transformer with
4 x 12-0-12VAC windings, except through MF.
SandyK

Hi Sandyk,

Thanks. I think I will do that and hope for the best or buy maybe a 250 to 300VA toroidal 12-0- 12VAC trans to try thru RS or Farnell. Ya, really overkill here but that will be much much better than the 20VA each from the MF trans secondaries. The sound should be olala, man! For the latter, b4 I can use it I better fuse them. What fuse rating do you recommned for 230VAC primary and 12 VAC secondary for drivng all things X V3?

[Deleted]

XTRProf
I would still try a cheap wallwart first, in case you have a major problem in the X-DAC.
If you are capable of safely wiring in a new ,larger toroidal transformer, are you also able to construct a small +-15VDC power supply board, obtainable in kit form from several sources, and also fit it in the original case ?
If you are able to safely do this, have a lookat page 4 of this area, where I describe a regulated PSU for the X-DAC V3, as well as some extreme modifications to th X-DAC V3.
Sandyk

[XTRProf]

sandyk said:

XTRProf
I would still try a cheap wallwart first, in case you have a major problem in the X-DAC.
If you are capable of safely wiring in a new ,larger toroidal transformer, are you also able to construct a small +-15VDC power supply board, obtainable in kit form from several sources, and also fit it in the original case ?
If you are able to safely do this, have a lookat page 4 of this area, where I describe a regulated PSU for the X-DAC V3, as well as some extreme modifications to th X-DAC V3.
Sandyk

Wow........, you guys are really the Xtremist pros and I love every minute of it, man. Guess I had found the right site to be around for some time. Ya, I will also like to know more on improving the X-PSU, X-10 and X-PSU V3. So shoot me to page 4 and where to get the parts for the xtreme mode later. But now really is to solve the immediate problem and get my X-dac and X-PSU running again after having being out for almost a month now due mostly to no reply from MF site.

[Deleted]

XTRProf
Don't also forget the other alternatives such as Mike's "Little Pinkie V3", for supplying individual X components. It is mentioned in another post today. (see below)
SandyK


(Please recommend amp for AKG K701
-Reply 5)

[XTRProf]

sandyk said:

XTRProf
Don't also forget the other alternatives such as Mike's "Little Pinkie V3", for supplying individual X components. It is mentioned in another post today. (see below)
SandyK


(Please recommend amp for AKG K701
-Reply 5)

Oh, is there? Let me have a look at what Pinkie have to offer. Thanks for the reference.

[PinkFloyd]

They're not fused?? so if the X-PSU is presented with a short circuit they go up in a puff of smoke bloody hell I'd always assumed they had an internal thermal trip fitted.... obviously not

[colin1958]

Hi XTRProf
Definetely without doubt go down the pinkie route for all your components.check out the masses of superb feedback for this fantastic piece of equipment.i originally had the MF X10V3 & XPSU,i used pink floyds mods for the x10v3 sold the xpsu & purchased the little pinkie v3i,never looked back.as i say check out the feedback they are amazing.
welcome to the forum.

[benzol]

Thanks for highlightinh the "fuse" problem. I just have got the stuff from M****n and will add it for extra security.

MF you are so ruthless.


Cheers

Benzol

[XTRProf]

benzol said:

Thanks for highlightinh the "fuse" problem. I just have got the stuff from M****n and will add it for extra security.

MF you are so ruthless.


Cheers

Benzol

WARNING: WHOEVER ATTEMPTING TO FOLLOW WHAT ARE PICTURED AND WRITTEN IN THIS THREAD, PLEASE NOTE THAT THERE ARE FATAL VOLTAGES HERE ESPECIALLY THOSE LIVING IN COUNTRIES FOLLOWING UK MAIN STANDARD OF 220 TO 240 VAC. BTW, I'M NOT IMPLYING THOSE IN 100 TO 120 VAC AREAS WOULDN'T BE FATAL. PLEASE ATTEMPT THEM IF ONLY YOU ARE KNOWLEDGEABLE AND CONFIDENT ENOUGH. I'M NOT LIABLE FOR ANY FATALITY IF YOU DO SOMETHING STUPID HERE. ANYWAY, I WANT ALL OF YOU WELL HERE AND NOT SOME DEAD SOULS SO THAT WE CAN HAVE MORE LIVELY AND KNOWLEDGEABLE EXCHANGE OF IDEAS IN THIS FORUM FOREVER.


Ya, they are ruthless in the sense of soundwise and forgotten about the safety side which any common hifi soul will be more happy with for the latter. Just imagine, as recommended by MF, the unit should be left on all the time to sound their best. What happened if you are not around and the trip circuit didn't work? Thank god, if your house is still around.








I'll post some internals of the X-PSU V3 later (Already posted 23rd Nov 2007. As above pictures. As can be seen no normal or any thermal fuses in the X-PSU V3 from all angles seen in pictures. Now MF trans kaput.) to give all here some ideas about what I meant and roughly how I will mode it to work again without using MF 4 12-0-12 VAC primary coils trans. Some rough ideas come to me while thinking are:


1) Use a say 300VA, or the biggest able to squeeze into the X-PSU box, toroidal with capabilities for 12-0-12 VAC to supply all the 4 outputs of the X-PSU in parallel. Since the the X-PSU single 12-0-12 VAC is only for 20VA, total for 4 will be 80VA or 160VA rated as specs for the MF trans. In using the 300VA trans, this will be about double that of the MF unit for even better sound.

2) Go individual trans to supply the 4 output circuits. But then can I squeeze in 4 toroidals rated at say, at least 60VA each, into the MF box to have an advantage over the VA rating of the MF trans?


Thinking about (2), I don't think it's feasible. Option (1), sounds feasible and worthwhile as now the 4 circuits will also be seeing the total of 150VA although being shared.

What do the experts here say? I can be wrong here and need correction from all the experts here.

[XTRProf]

sandyk said:

XTRProf
Why don't you just puchase a cheap 12-0-12 VAC 500mA (or 1 Amp) wallwart to check your X-DAC with ? I doubt very much that you will be able to buy another toroidal transformer with
4 x 12-0-12VAC windings, except through MF.
SandyK

Hi Alex,

I now have a MF original wallwart that states primary 230VAC 77mA and secondary 24VAC 500mA. Yes, I did opened up this MF wallwart and again it's unfused (Pictures already uploaded 23rd Nov 2007 and shown below) and I have to fuse it b4 testing my X-Dav with it. What do you recommend for fuse rating? 230VAC 50mA fast blow fuse for Primary and 200mA fast blow for each of the 12VAC secondary hot wires? Thanks.

[XTRProf]

admin said:

They're not fused?? so if the X-PSU is presented with a short circuit they go up in a puff of smoke bloody hell I'd always assumed they had an internal thermal trip fitted.... obviously not

Ya, not fused and that was what happened to my unit.


Wow, you are Pink Floyd. Ha, ha, ha, I'm meeting the great Dave Gilmour or Roger Waters. Salute, man! I love DSOTM and The Wall. The rest like Meddle and Wish You Were Here are also very good sounding. Hey, how you did it ............. He, he, he .........

[XTRProf]

colin1958 said:

Hi XTRProf
Definetely without doubt go down the pinkie route for all your components.check out the masses of superb feedback for this fantastic piece of equipment.i originally had the MF X10V3 & XPSU,i used pink floyds mods for the x10v3 sold the xpsu & purchased the little pinkie v3i,never looked back.as i say check out the feedback they are amazing.
welcome to the forum.

Ya, that could be one of the option opened. But thinking of the 150VA 12-0-12 VAC toroidal route compared to Pinkie 30VA route, hmmm .........., I wonder about the sound. But don't worry that option is not closed yet and I still need to check whether the X-Dac V3 is working first with the MF wallwart moded with fuses.

[Deleted]

XTRProf
Probably not a good idea to pull apart a wallwart for safety reasons. Why not just cut each of the active leads, i.e. not the lead that goes to the centre pin of the 3 pin DIN plug, and insert an inline car radio type fuse holder (3AG) in each leg. Try 250mA fast blow fuses initially to see if there is a major problem. Most fast blow fuses blow very quickly at double their rating.
SandyK

[XTRProf]

sandyk said:

XTRProf
Probably not a good idea to pull apart a wallwart for safety reasons. Why not just cut each of the active leads, i.e. not the lead that goes to the centre pin of the 3 pin DIN plug, and insert an inline car radio type fuse holder (3AG) in each leg. Try 250mA fast blow fuses initially to see if there is a major problem. Most fast blow fuses blow very quickly at double their rating.
SandyK

Hi Alex,

Actually, not much of problem as the MF wallwart is screwed type and can be unscrewed and screwed back on. Thansk I'll try 250mA for the 2 12 VAC hot wires. For primary, 250VAC 77 mA fast blow? Thanks.

[Deleted]

XTRProf
I wouldn't worry about a primary fuse.
TBH, Mike and myself try to discourage people from doing things like that for safety reasons. 240V is VERY unforgiving !! Far better to do it externally on the low voltage secondary side.
YOU may be experienced enough to do it safely, but some less experienced person may try to do likewise, with perhaps fatal results.
Alex

[XTRProf]

sandyk said:

XTRProf
I wouldn't worry about a primary fuse.
TBH, Mike and myself try to discourage people from doing things like that for safety reasons. 240V is VERY unforgiving !! Far better to do it externally on the low voltage secondary side.
YOU may be experienced enough to do it safely, but some less experienced person may try to do likewise, with perhaps fatal results.
Alex

Yes, Alex, you are right. Although I wouldn't claim to be an expert in the electronic field but I should be knowledgeable enough given some good advice. I better put up some warning sign for anyone attempting what I'm doing. So to all, please read WARNING above.

To all, I will post some pictures once taken as I don't have the time to do it now. So far had already bought the fuse holders (250VAC, 6.3A type) and the 250mA 250VAC fast blow fuses.

[XTRProf]

WARNING: WHOEVER ATTEMPTING TO FOLLOW WHAT ARE PICTURED AND WRITTEN IN THIS THREAD, PLEASE NOTE THAT THERE ARE FATAL VOLTAGES HERE ESPECIALLY THOSE LIVING IN COUNTRIES FOLLOWING UK MAIN STANDARD OF 220 TO 240 VAC. BTW, I'M NOT IMPLYING THOSE IN 100 TO 120 VAC AREAS WOULDN'T BE FATAL. PLEASE ATTEMPT THEM IF ONLY YOU ARE KNOWLEDGEABLE AND CONFIDENT ENOUGH. I'M NOT LIABLE FOR ANY FATALITY IF YOU DO SOMETHING STUPID HERE. ANYWAY, I WANT ALL OF YOU WELL HERE AND NOT SOME DEAD SOULS SO THAT WE CAN HAVE MORE LIVELY AND KNOWLEDGEABLE EXCHANGE OF IDEAS IN THIS FORUM FOREVER.



As promised, I had posted some pictures on my solutions to solving the problem. First up, is to get the MF wall wart to test whether the X-Dac V3 is the problem of the short causing my X-PSU to go up in smoke. But more in-depth preliminary diagnosis of the X-PSU V3 is in order to understand the problem better. Invariably, some measurements with a MM or DMM will be in order for that.

1) Measuring all 4 primary coils individually of the kaput MF trans for continuity and all were well. Also, measured whether there was any shorts between primary coils individually and there were none. Lastly, measured any shorts between all 4 primary coils individually and the secondary coils and again negative.

Conclusion: All 4 primary coils are working and still in good health showing that the transfomer short is not from the primary coils or caused by the X-Dac V3. If the X-Dac V3 caused it, one of these coils should have gone first and became open circuit but all was well here. Whew........, now I'm more at ease.

2) Measured the primary coils for continuity and there was continuity in the 115 VAC coil but open circuit in the 230 VAC side.

Conclusion: The MF trans had shorted in the 230 VAC coil causing the the MF trans to go kaput. This showed sign of lamination between coils problem. In other words, quality problem with the MF trans. Since the X-PSU V3 was made in Taiwan, this was most probable but not definite since the batch could have passed the AQL % then and missed this bad one in that batch.

Next coming up is how I modded the MF wall wart to test the X-Dac V3 for any operation faults if have. But the chance is high the X-Dac is all well as well from the conclusion as above. But we can't be certain until we have tested it, isn't it? So follow me ...............

[XTRProf]

WARNING: WHOEVER ATTEMPTING TO FOLLOW WHAT ARE PICTURED AND WRITTEN IN THIS THREAD, PLEASE NOTE THAT THERE ARE FATAL VOLTAGES HERE ESPECIALLY THOSE LIVING IN COUNTRIES FOLLOWING UK MAIN STANDARD OF 220 TO 240 VAC. BTW, I'M NOT IMPLYING THOSE IN 100 TO 120 VAC AREAS WOULDN'T BE FATAL. PLEASE ATTEMPT THEM IF ONLY YOU ARE KNOWLEDGEABLE AND CONFIDENT ENOUGH. I'M NOT LIABLE FOR ANY FATALITY IF YOU DO SOMETHING STUPID HERE. ANYWAY, I WANT ALL OF YOU WELL HERE AND NOT SOME DEAD SOULS SO THAT WE CAN HAVE MORE LIVELY AND KNOWLEDGEABLE EXCHANGE OF IDEAS IN THIS FORUM FOREVER.




As can be seen in Fig 1, the MF wallwart is screwed on cover type. So opening up the wall wart will be easy and straight forward. Well, not those sealed SMPS wallwart to recon with and making the job a piece of cake. But please be warned, there is fatal voltage here, so do so only if you know what you are doing and with confidence. Don't say, I didn't warn you, ok? Sorry for the photos being a bit blur as these were taken with a HP cam with no macro feature for close clear shots.





Fig 1



As can be seen in Fig 2, the internals of the MF wallwart also doesn't have any fuses to protect itself. So we have to deploy some protection "agencies" via fuses before it can do it's job without getting killed when testing the X-Dac V3. The next Fig will exemplify that.







Fig 2


In Fig 3, I had soldered the fuses to the secondary coils as arrowed. After, this I had to test whether there was any continuity between the 3 pins of the DIN plug output and the secondary coils thru the soldered fuse holders using a MM. Here, some shrink insulation tubing (Pinky shrink tubes in my case. Hmmm, sorry no relation with Pinkie here. ) were used to cover the soldered terminals at the fuse holders end if permissible. Then visual inspections were made to ensure no short circuits between the coils before closing up the MF wallwart.





Fig 3



Testing coming up .............., sir! Yes, sireeeeeeeeeee....................

[XTRProf]

WARNING: WHOEVER ATTEMPTING TO FOLLOW WHAT ARE PICTURED AND WRITTEN IN THIS THREAD, PLEASE NOTE THAT THERE ARE FATAL VOLTAGES HERE ESPECIALLY THOSE LIVING IN COUNTRIES FOLLOWING UK MAIN STANDARD OF 220 TO 240 VAC. BTW, I'M NOT IMPLYING THOSE IN 100 TO 120 VAC AREAS WOULDN'T BE FATAL. PLEASE ATTEMPT THEM IF ONLY YOU ARE KNOWLEDGEABLE AND CONFIDENT ENOUGH. I'M NOT LIABLE FOR ANY FATALITY IF YOU DO SOMETHING STUPID HERE. ANYWAY, I WANT ALL OF YOU WELL HERE AND NOT SOME DEAD SOULS SO THAT WE CAN HAVE MORE LIVELY AND KNOWLEDGEABLE EXCHANGE OF IDEAS IN THIS FORUM FOREVER.




It's time to face the music and here goes. Hmmm, I wish that was the case and how nice literally. No, no, it's time to face the "electric chair" .............

The first candidates (Yes, ma....ma...., fuses only and not for real) for the "electric chair' were the bought F250mA 250 VAC fuses pair. With the MF wallwart and 230 VAC switched on unloaded, there was no sudden death yet. Thank God! Measuring the secondary coils with a DMM gave a 14.3 VAC at both. So still very much alive! To test it further, it was time to subject them with some load and what better candidate than the X-10 V3 to stretch them. The X-10 V3 was a known working unit and so should work with the moded MF Wallwart. He, he......, time to give the candidate the killer punch and if they ever survived, they would be pardoned from the "electric chair" to go scot free, immuned from any further sentences. So what was the story. Well, read on ..............., dude

Sorry, to say the candidates had RIP in a buff of smoke! OMG. , Maybe time to play some rock music form the rock group Smokie. Then I didn't have any other fuses to test it. So F250 mA was not to be for loaded application althought the bloody specs on the MF wallwart cover stated that. Hmmm, what then?? Aha, I still had another 2 candidates in my box. F1.5A 250 VAC "bouncer" type fuses for secondary protection. So back to the drawing board it seemed .............

With the F1.5A fuses in, the result was as Fig 4.




Fig 4



So Now morale, all of a sudden, cloud 9 ................


Next, the mother of all test I had been waiting for months while wasting time with MF. And this went like Fig 5.





Fig 5



Having gone cold turkey for about 2 months without the X-Dac V3 operational, I just have to go now to have back music from this creature. So chapter temporary close now as I just have to have the "shots" from this creature again to let go internal steam like a man!

Coming will be what I will settle for the fuse rating. This I have to buy the various fuses first for the "electric chair" again when weekend comes. THE END.

[mrarroyo]

I thought the wallwart can only produce 500 mA? If so, wouldn't a 1.5 A be way to high?

[PinkFloyd]

For the fuses on the secondaries you are looking at something like T63mA or thereabouts (time delay). I use T160mA (time delay) on the secondaries of a 30VA transformer (approx 2500mA) 1.5amp is WAY overrated. A T1.25mA (time delay) on the primary of a 30VA transformer is about right. Remember also to increase the fuse rating if you are using 115V.

[mrarroyo]

Mike, you are supposed to be on a sabbatical! Go and rest.

[XTRProf]

mrarroyo said:

I thought the wallwart can only produce 500 mA? If so, wouldn't a 1.5 A be way to high?

Hiya mrarroyo,

Yes, that's way too high. That's why I wrote "bouncer" type fuses for only secondary protection. I'm only using them as I didn't have anymore fuses then on hand and used those meant for poweramps that I recalled I had some in a box. I had already got some more fast blow fuses (F) over the weekend to try and the results are as below.