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NEW MFW-15 amps (May 2010) *pics* - Page 81

post #2401 of 2590
[SIZE=4 THANKS FOR THE ADVICE]i WILL GIVE IT A GO LATER TODAY AND LET ALL KNOW HOW I MADE OUT. THIS MFW-15 SUB MATTER HAS TOO MANY FOLKS SCREWED OVER THANKS TO OUR JAIL BIRD FRIEND.

THANKS TO THE GOOD GRACES OF MURRELL AND SEVERAL OTHER TALENTED MEMBERS, SOME OF YOU HAD YOUR ISSUES FIXED.

i HOPE i CAN JOIN THAT LIST ( ECONOMICALLY) [/SIZE]
post #2402 of 2590
There is no glue but there is a foam gasket that after time and heat has sort of stuck everything real good. also the finish may not have been cured completely before they installed the amp

Take a razor blade and go around the edge of the plate
take a short piece of wire connect it to the binding posts to make a pull handle and PULL

Once out you can then see if the caps are bad, directions are posted here in the thread on how to replace them or I can email them
post #2403 of 2590
This will be tomorrows project.....Right now I'm looking at about 10" of snow out my front & back doors.......putting off snow blowing .winds in the 30-40mph range...... hoping they die down....rolleyes.gif
post #2404 of 2590
hOW CAN JUST LOOKING AT THEM INDICATE IF THE caps ARE BAD.......?

i'LL TAKE YOU UP ON YOUR OFFER OF INSTRUCTIONS.....smile.gif
post #2405 of 2590
If the capacitors are bad, you will notice that the tops of them have 'puffed out' and are 'swollen'.

I did the 'hum fix' on 1 amp, replacing the pair of 470uF capacitors that were obviously bad. The other capacitors (the 1000uF and the 22uF) looked 'fine', so I left those alone. Re-installed the amp, and the subwoofer went from dead to working again, but with a very slight audible hum. Despite turning the amp onto 'off' position, I noticed the amp still quite warm despite not using it for hours. I then just unplugged the thing altogether...

On my other MFW-15, I ended up cutting out a section of MDF in the size of the amplifier plate, putting on some binding posts. I also decided to pull the woofer out, and replaced it with a Dayton 15" woofer (decided to take a flyer...)

http://www.parts-express.com/pe/pshowdetl.cfm?&Partnumber=295-514

I wired it in serial to get a 4 ohm load, and hooked it up to an external amp (initiallly an old adcom gfa555 II in mono mode, then switched to a behringer europower epx3000). We'll see how it sounds after it breaks in...

Should have just gotten a SVS subwoofer altogether I think...
Edited by doctor subie - 3/21/13 at 5:40pm
post #2406 of 2590
Quote:
Originally Posted by doctor subie View Post

If the capacitors are bad, you will notice that the tops of them have 'puffed out' and are 'swollen'.

I did the 'hum fix' on 1 amp, replacing the pair of 470uF capacitors that were obviously bad. The other capacitors (the 1000uF and the 22uF) looked 'fine', so I left those alone. Re-installed the amp, and the subwoofer went from dead to working again, but with a very slight audible hum. Despite turning the amp onto 'off' position, I noticed the amp still quite warm despite not using it for hours. I then just unplugged the thing altogether...

Would you say, that you should have replaced the other questionable components and be done with it, thereby providing certainty that your assessment of "IFFY" components were accurate or NOT? How much more time and money would you have invested to be truly certain your assessment was correct ?

Please understand, I am not taking cheap shots....just seeking more info and certainty before I go digging around what may be an easy to fix issue.

There is no doubt, this hum issue has been plaguing we all since it was identified a couple of years ago..... Had these subs been a few Hundred $ instead of several $000 plus delivery then, just right it off to a lousy company...... I hope that Mark Shifter has an ample supply of lubricant for the new few years....smile.gif

I still wish our member Morrell was offering repair services...... His repairs solved the matter under discussion...... ( HEAR THAT MORRELL !!!!!!)
post #2407 of 2590
Quote:
Originally Posted by ginovino View Post

Quote:
Originally Posted by doctor subie View Post

If the capacitors are bad, you will notice that the tops of them have 'puffed out' and are 'swollen'.

I did the 'hum fix' on 1 amp, replacing the pair of 470uF capacitors that were obviously bad. The other capacitors (the 1000uF and the 22uF) looked 'fine', so I left those alone. Re-installed the amp, and the subwoofer went from dead to working again, but with a very slight audible hum. Despite turning the amp onto 'off' position, I noticed the amp still quite warm despite not using it for hours. I then just unplugged the thing altogether...

Would you say, that you should have replaced the other questionable components and be done with it, thereby providing certainty that your assessment of "IFFY" components were accurate or NOT? How much more time and money would you have invested to be truly certain your assessment was correct ?

Please understand, I am not taking cheap shots....just seeking more info and certainty before I go digging around what may be an easy to fix issue.

There is no doubt, this hum issue has been plaguing we all since it was identified a couple of years ago..... Had these subs been a few Hundred $ instead of several $000 plus delivery then, just right it off to a lousy company...... I hope that Mark Shifter has an ample supply of lubricant for the new few years....smile.gif

I still wish our member Morrell was offering repair services...... His repairs solved the matter under discussion...... ( HEAR THAT MORRELL !!!!!!)
Unfortunately, Mark Schifter got a slap on the wrist and, as far as I know, never did jail time. I had a personal dealing with him a few years back and he never paid me.

I did the amp replacement for the MFW-15 and was quite happy with it. Sorry you are having trouble with it.
post #2408 of 2590
Quote:
Originally Posted by ginovino View Post

Quote:
Originally Posted by doctor subie View Post

If the capacitors are bad, you will notice that the tops of them have 'puffed out' and are 'swollen'.

I did the 'hum fix' on 1 amp, replacing the pair of 470uF capacitors that were obviously bad. The other capacitors (the 1000uF and the 22uF) looked 'fine', so I left those alone. Re-installed the amp, and the subwoofer went from dead to working again, but with a very slight audible hum. Despite turning the amp onto 'off' position, I noticed the amp still quite warm despite not using it for hours. I then just unplugged the thing altogether...

Would you say, that you should have replaced the other questionable components and be done with it, thereby providing certainty that your assessment of "IFFY" components were accurate or NOT? How much more time and money would you have invested to be truly certain your assessment was correct ?

Please understand, I am not taking cheap shots....just seeking more info and certainty before I go digging around what may be an easy to fix issue.

There is no doubt, this hum issue has been plaguing we all since it was identified a couple of years ago..... Had these subs been a few Hundred $ instead of several $000 plus delivery then, just right it off to a lousy company...... I hope that Mark Shifter has an ample supply of lubricant for the new few years....smile.gif

I still wish our member Morrell was offering repair services...... His repairs solved the matter under discussion...... ( HEAR THAT MORRELL !!!!!!)


I'll try to answer your questions Gino:

1) not sure if you've downloaded the "MFW-15 Hum fix" pdf document, you can google it, and look at the picture on there. It will show you what capacitors might need replacing. The red-circles on the picture are just a little bit off, but you will get an idea of where the capacitors are, generally.

2) you should probably only attempt to fix it yourself if you are either handy, or can solder. You will need to de-solder in order to remove the bad capacitors, then re-solder the new ones on. You should be able to buy new capacitors online, or at a local electronics store that sells capacitors (not a Best Buy type store). Again, you can look up on youtube videos of how people de-solder and re-solder. This is what I did, I am not an expert solderer, just a beginner.

3) Even after you manage to do this fix and get your MFW up and running, I would STRONGLY recommend turning your MFW's COMPLETELY OFF, not just by using the on/off/standby switch in the back of the subwofer, but actually powering the whole unit off so the red LED is not lit any more. On mine, even on 'standby' mode and 'off' mode, the amp was warm. Maybe this caused the units to fail in the long run?

Good luck. the fix is actually easy. Alternatively, you can probably find a TV-repair or electronics repair shop and have them do the repair for you, showing them the .pdf file of what needs repairing. Shouldn't cost you much in labor, and the parts are literally $3...
post #2409 of 2590
The guidance provided by MTATech through his step by step parts replacement, helped greater than he realizes. His advising the amp still hums to "SOME" degree even after some of the parts were replaced was valuable. Especially to us who are willing to make an attempt ( I do have have very limited soldering skills. I have done work on both a Sansui G901 and a G9700 converting their ancient spring loaded speaker clips to the standard "banana plug / screw down type. I t required taking the covers off and finding the speaker wiring and replacing it, then soldering to the new plugs.

I was able to use the current size and brand of upscale speaker cables ( Kimber, Audioquest, Straightwire etc, to name just a few. Today's more exotic cables greatly improved the sonics of these very fine 70-80's units.

Dr. Subies comments are welcomed and succinct. Should I use a typical "Weller" 140 -100 or a single wattage 30 watt with a wide tip? ( I may be able to buy a narrower tip).

Hints please !!! You mentioned "desolder" how much is needed? What other wiring must I take heed with?

Your comments about shutting (powering) down the subs entirely has merit. As these units are likely to require no more than 15amps each under the FULL load ( which is unlikely to happen). Its note big deal to plug them in before each use. I have several Monster Cable Power managers for my 2 channel Bryston 7b-st amps, preamp, DAC, CD, and my Tuner collection. Plus another pair of Power managers for my home theater amps, subs. etc.

So for the purpose of REAL ON -OFF switching I could use the Monsters.

Dr.Subies, upon completion of your repair... did you encounter "Hum" low level or NONE at all?

Do you use power cables other than what was provided by MFW? When the unit is question was operating, I tried both and a few retail ( mail order) 15amp units... MFW's unit was somewhat thin...vs. the mail order power cord. ( should anyone have an interest, PM me and I'll sent you the links..... The prices are more than right! No $500 cable for ME !

I look forward to any and all comments wink.giftongue.gif Thanks in advance!
post #2410 of 2590
Gino

Do not use a big honking Weller 140W iron just a good old 30W or so from something like radio shack or Parts Express is fine.
Before I got my Vac desloder station, for something like cap replacement you can try a desolder bulb but I never have luck. What I would do is just heat and rock so one leg would pull up, then swap to the other leg. then use the desolder bulb to just blow the hot solder out of the hole. Its crude but does work. Just try not to get to much heat into the board.
post #2411 of 2590
So it looks like you are handy, Gino. You shouldn't have any problem replacing these caps, and once you get the hang of it, you'll look at all your broken electronics differently! Since replacing 2 caps on one MFW15 amp, I plan to fix up my Buttkicker BKA1000 transducer amp (see pics on another thread in this section) that had catastrophic caps failure (at least 2 caps).

My other MFW15 amp has more damage than I realized. In addition to the bulging capacitors, there is 1 ceramic disc capacitor that has burned out also. I plan to try to repair that.

I also have a HSU VTF mk3 sub that has an amp go bad--I pulled the plate amp, but can't find any blown caps--might end up just replacing that amp.

Anyhow, some additional newbie-soldering advice:

1) I would buy a decent temperature-adjustable soldering iron, from a reputable maker. I have a Weller WESD51 station, cost me $150. It should be the last one I need to buy. You could use a soldering pencil, but those do not have adjustable temperature, which might come in handy as you work with more delicate parts... You can probably get a decent solder station for ~$50 or so...

2) Which type of solder tip? Well, I got my advice after scouring the internet, and have found that a small, flat chisel-tip works well. Pencil tip style would take a long time to heat up the joint for de-soldering.

3) Don't use a solder-gun. It's too high power, and can damage the board. Plus, the tips on those are too big for this job.

4) There are different ways to desolder, but I used a desoldering wick. Worked well.

5) When I first tried to do this, I had soldered only a few times. I wasn't having success at desoldering the bad cap, and was wondering why. Turns out I had an old tip on the solder iron that was heavily oxidized. Put a new tip on, tinned it properly, and it now works like a charm.

6) I got the bulk of my advice from this youtube video (and subsequent ones): http://www.youtube.com/watch?v=J5Sb21qbpEQ The guy is very entertaining!

7) As for how to turn on/off these subwoofer amps, I'm possibly looking into a Furman-type unit, as was recommended by someone in the Buttkicker thread...
http://www.furmansound.com/product.php?div=01&id=PS-8R_II

Good luck, let me know how things go
post #2412 of 2590
Quote:
Originally Posted by doctor subie View Post

I'll try to answer your questions Gino:

1) not sure if you've downloaded the "MFW-15 Hum fix" pdf document, you can google it, and look at the picture on there. It will show you what capacitors might need replacing. The red-circles on the picture are just a little bit off, but you will get an idea of where the capacitors are, generally.

2) you should probably only attempt to fix it yourself if you are either handy, or can solder. You will need to de-solder in order to remove the bad capacitors, then re-solder the new ones on. You should be able to buy new capacitors online, or at a local electronics store that sells capacitors (not a Best Buy type store). Again, you can look up on youtube videos of how people de-solder and re-solder. This is what I did, I am not an expert solderer, just a beginner.

3) Even after you manage to do this fix and get your MFW up and running, I would STRONGLY recommend turning your MFW's COMPLETELY OFF, not just by using the on/off/standby switch in the back of the subwofer, but actually powering the whole unit off so the red LED is not lit any more. On mine, even on 'standby' mode and 'off' mode, the amp was warm. Maybe this caused the units to fail in the long run?

Good luck. the fix is actually easy. Alternatively, you can probably find a TV-repair or electronics repair shop and have them do the repair for you, showing them the .pdf file of what needs repairing. Shouldn't cost you much in labor, and the parts are literally $3...

Could you provide me a better picture of the board shown..... mine has been around so long that it grew a beard! The circles around the components to be replaced aren't very succinct.... It looks like only ONE CAP needs to be changed on the left ????? and those on the right side....well, you know.... I am going to order the parts once I have pix.

Next issue.... do you suggest a brand of replacement parts?

I refuse to go to "RAT Shack"..... Those folks have a tough time finding the "john"!

I await your response.....thanks
post #2413 of 2590
I'll try to point them out. BTW, just google "MFW15 hum fix", and i'm sure you'll find the .pdf file. Alternatively, I can email that to you.

Here is a pic of the circuit board you need to remove from the amplifier.

Basically, the capacitors that typically need replacing are the small cylindrical ones (not the 4 big black caps). The 2 to the right of the big black cylinders/caps, and the 2 to the left. Again, the specific resistance/voltages of the caps are listed on the .pdf file.

If the capacitors are 'blown' or bad, they will look like this:



Notice how the tops of them are 'puffed out'?

I got my parts from Partsexpress.com.

Hope this helps!
post #2414 of 2590
Thanks for the pix..... but you reversed them!!!!! and, damn near confused me!!!!!

Do you have a copy of the (Murrell) pix I posted some time back, showing the circles, arrows and sizes of the parts needed ? I cant find mine!!!!!!!
post #2415 of 2590
attached is pix of what I think your talking about.
post #2416 of 2590
Sorry to admit..I don't know a disc cap from an electrolytic..... I can see from the pix on the Parts express page, CAPS come in all shapes and sizes....
of the 4 I need... which is which ??????: :confused:eek:
post #2417 of 2590
Quote:
Originally Posted by ginovino View Post

Thanks for the pix..... but you reversed them!!!!! and, damn near confused me!!!!!

Do you have a copy of the (Murrell) pix I posted some time back, showing the circles, arrows and sizes of the parts needed ? I cant find mine!!!!!!!


Post 2361 a couple of pages back you will find the PDF


Murrel
post #2418 of 2590
I'm sure this is answered somewhere in this thread but I need to find a decent replacement amp for my MFW-15... Anyone have links?

Thanks!
post #2419 of 2590
Quote:
Originally Posted by ginovino View Post

attached is pix of what I think your talking about.


you are correct, those 2. Also, some folks need to replace the 2 caps on the far left. Let me know if you can't find Murrel's pdf file, I can email that to you...

Murrel's pdf will spell out exactly the capacitors you need to buy...
post #2420 of 2590
Quote:
Originally Posted by USlivingCanuck View Post

I'm sure this is answered somewhere in this thread but I need to find a decent replacement amp for my MFW-15... Anyone have links?

Thanks!

I think you might be out of luck, unless you go for a turbo kit from Motor City Custom (and I'm not sure what the lead times on those are). If your amp isn't repairable, then your best bet would be to just bypass the amp altogether and hook it up to a external amp...
post #2421 of 2590
Quote:
Originally Posted by doctor subie View Post

Quote:
Originally Posted by USlivingCanuck View Post

I'm sure this is answered somewhere in this thread but I need to find a decent replacement amp for my MFW-15... Anyone have links?

Thanks!

I think you might be out of luck, unless you go for a turbo kit from Motor City Custom (and I'm not sure what the lead times on those are). If your amp isn't repairable, then your best bet would be to just bypass the amp altogether and hook it up to a external amp...

Kevin does the final mods and packing up to order, but the kits are readily available now. You can also watch the Motor City Custom Audio forum for those who upgrade to offer some old amps for sale.
post #2422 of 2590
I wish I had gone with a turbo kit rather than trying to piece together my own components to make something similar...
post #2423 of 2590
Can anyone direct me to member who repaired his own sub and THEN, when about trying out different values of CAPS, all the way up to 4000uf ( I think)..

He was providing an ongoing update as to his success and how the sub sounded as he made each CAP modification..... I would love to read through the write up as I am at the beginning to replace the bad CAPS in my unit.....
post #2424 of 2590
I cant remember who it is but I am almost sure its in THIS thread

Quote:
Originally Posted by ginovino View Post

Can anyone direct me to member who repaired his own sub and THEN, when about trying out different values of CAPS, all the way up to 4000uf ( I think)..

He was providing an ongoing update as to his success and how the sub sounded as he made each CAP modification..... I would love to read through the write up as I am at the beginning to replace the bad CAPS in my unit.....
post #2425 of 2590
Hey all -- Hoping someone here can help me out with this.

Last night I plugged in my MFW-15 and all I'm getting out of it is a loud hum. Happens without the LFE cable inserted. LFE cable doesn't correct it. Multiple outlets, with everything else unplugged, even using the 3 to 2 prong adapter, loud hum. Very loud.

Now the thing I'm concerned about is that this happened out of nowhere. The subwoofer had been unplugged for 3 months, we plugged it back in, and now we get the hum.

So I've come here for research and the following is my understanding:

My options:

1_) Re-solder the caps as mentioned multiple times gifted by Murrel.
2_) Buy the complete upgrade kit sold by Sandbagger
3_) Purchase a new subwoofer system.


Now, I'm looking to get out of this as cheaply as possible. I'm currently financing a new home and a new business simultaneously while getting married. I'm broke. I have some experience soldering electronics. Do you guys experienced with this believe this will work for me? Or is getting the Turbo kit the best way out of this financially? Can I get any single sub setups that'll put me in a better situation than the Turbo will for the money? Using a Marantz SR-7005 with 4x X-Statik + X-Voce.

I appreciate good audio but I will be the first to admit I do not know as much as most of you guys on here. I greatly appreciate any advice I can be given.

Thank you in advance.
post #2426 of 2590
If you can solder then you should have no problem replacing the caps and its only a few dollars in parts.
If its got the hum, good chance the cap fix it, for how long is a whole other question though.

Kevin
Quote:
Originally Posted by luceri84 View Post

Hey all -- Hoping someone here can help me out with this.

Last night I plugged in my MFW-15 and all I'm getting out of it is a loud hum. Happens without the LFE cable inserted. LFE cable doesn't correct it. Multiple outlets, with everything else unplugged, even using the 3 to 2 prong adapter, loud hum. Very loud.

Now the thing I'm concerned about is that this happened out of nowhere. The subwoofer had been unplugged for 3 months, we plugged it back in, and now we get the hum.

So I've come here for research and the following is my understanding:

My options:

1_) Re-solder the caps as mentioned multiple times gifted by Murrel.
2_) Buy the complete upgrade kit sold by Sandbagger
3_) Purchase a new subwoofer system.


Now, I'm looking to get out of this as cheaply as possible. I'm currently financing a new home and a new business simultaneously while getting married. I'm broke. I have some experience soldering electronics. Do you guys experienced with this believe this will work for me? Or is getting the Turbo kit the best way out of this financially? Can I get any single sub setups that'll put my in a better situation than the Turbo will for the money? Using a Marantz SR-7005 with 4x X-Statik + X-Voce.

I appreciate good audio but I will be the first to admit I do not know as much as most of you guys on here. I greatly appreciate any advice I can be given.

Thank you in advance.
post #2427 of 2590
Quote:
Originally Posted by sandbagger View Post

I cant remember who it is but I am almost sure its in THIS thread

It was in post 2169, link here:

http://www.avsforum.com/t/1250559/new-mfw-15-amps-may-2010-pics/2160#post_21788287

Maybe someone can PM him and ask him how he wired the additional caps in parallel, and how he fit the extra board onto the amp plate...
post #2428 of 2590
Agree with Kevin--replacing the capacitors, esp. if you can solder, is an ultra cheap option. If it works, great, if it doesn't, you're out only a few dollars, literally.

My only other advice, if you go the fix-it route, would be to manually turn off the sub when you are done (don't leave it on standby, or even with the switch turned to 'off'). I noticed that the back of the amp was pretty warm, even when on standby as well as 'off'. I'm guessing the heat from leaving it in constant standby mode contributed to the caps drying out/blowing. I'm going to hook my subs to a simple surge suppressor separate from the rest of my electronics, so that I can manually turn it on/off when I'm done...
post #2429 of 2590
Alright thanks guys. I'm going to give it a shot this week. Broke out the old soldering iron from college days and will let you know how it goes.

I've experienced the same heat issues and know what you're talking about with that. You don't think the initial bursts of electricity to the caps is not going to cause more damage than just leaving it on? Just too hot eh? Maybe a custom cooling solution would be worth it if we can find a 12v/gnd and just put a cheap PC fan on the piece. I've spent time on worse things.

This is a really good resource to have found for my problem. Thanks a lot guys.
post #2430 of 2590
Well, the argument kind of reminds me about whether one should power down their computer, or just leave them constantly on...for these MFW15 amps, they seem to run hot, so I'm betting that powering off will prolong their lifespan.

Plus, I think I read somewhere that on 'standby' mode, it ends up costing about $30/month in electric bills (assuming average price per kilowatt). I have 2 of these damn things, so I'd rather just save some $!

Good luck with the fix--depending on how old your soldering iron is, you may need to at least replace the tip, if not just ponying up for a decent iron. I was having no luck de-soldering until I realized my old tip was super oxidized!


Quote:
Originally Posted by luceri84 View Post

Alright thanks guys. I'm going to give it a shot this week. Broke out the old soldering iron from college days and will let you know how it goes.

I've experienced the same heat issues and know what you're talking about with that. You don't think the initial bursts of electricity to the caps is not going to cause more damage than just leaving it on? Just too hot eh? Maybe a custom cooling solution would be worth it if we can find a 12v/gnd and just put a cheap PC fan on the piece. I've spent time on worse things.

This is a really good resource to have found for my problem. Thanks a lot guys.
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