MS Capacitor Replacement

[KUB3]

Yes, I have about four of the cap threads bookmarked.

I am taking my time with the rebuilds, fitting in an hour or two here and there. There is no deadline so it will be done as thoroughly as I can. The individual brass / gold components and all screws have been ultrasonically cleaned so far. Next I was debating using a cloth dampened with turps or lighter fuel to polish the circuit boards when I've finished all the soldering.

[nico boom]

No polishing recommended; I only clean with what we call "spiritus" I believe it's a purified alcohol [not for drinking].
Workes real fine when you got the right way of applying, and removing quick enough; goooold shine again.

[KUB3]

Sorry, I didn't actually mean to say polish. Just a wipe as you say. I guess there are loads of products with alcohol in them that may work fine.

[Txsaxkat]

I have done recaps on my m44 m50 but now Im on the ms250 and its alot more work. I didnt get the main rail caps for any of them but I fell it would be a mistake not to do them also on the ms250 since its so much work to get it apart. The m50 & 44 are easy to take apart so no big deal. So Im making another order from digikey and was wondering are their any smaller caps like the ones mentioned in the m class that need to be replaced like c15 & c16. I also want to say thanks for all the info shared on the board after recapping the m44 I put it in the wifes car it has some diamond audio hex series seperates with silk tweeters and I was running a mb quart pab4100 what a turd that amp was the m44 blows it out of the water with half the claimed wattage.

Jimmie

[Altered States]

Hi,

Nice work everyone. Some of the soldering does need a bit more practice. Then again as part of my job I attended a school for two months to learn nothing but soldering.

Some tips to help with other projects:

- To this day I still have the voices of my instructors saying, "Round, Smooth, Shiny, Concave fillets!" . So the finished work should be shiny, round or square depending on the pad, and smooth. Any pitting means there is contamination or other reasons.

- Tinning prior to installation. Makes for a cleaner job. Can also help remove any contamination.

http://www.mediacollege.com/misc/solder/tinning.html
The site belongs to a college but the photo's are absolute crap. Seeing that quality of work is like having someone pulling their finger nails across a chalk board.

- Never leave the irons tip on the board for to long. It will over heat the board and burn it. This in turn will lift the pads from the board. It will also damage the board leaving what is called measling. It is also progressive so if you have to work on the same site several times it will continue to get worse. Then the board will need to be repaired.

- Clean up with 90-100% ISP. Where I live the local Safeway store carries 99% Isopropyl for a couple bucks. Prefect for projects.
Buy some small acid brushes. Trim them in half and use one time. Then toss away. This will help avoid contamination.
http://www.wassco.com/Products/Acid-Bru ... 31093.aspx
We used special cotton tips to gently polish off and residue.


Usual sales disclaimer: The links I posted are just examples. I don't work for any of these companies, schools, nor have done any business with them.

[Lance_S]

I swapped out caps on a MS275 and two MS2125's today. Just the power caps, not the rail caps. Did the 2125's in about 2 hours per unit, not bad. Followed the tutorial, worked like a charm. Thanks to all that have added to the thread. Amps were BNIB so I actually didn't expect to see any leakage......ummmm, most of them were leaking. If you haven't changed them out yet, do it today. These had 0 time on them and they were still leaking (one white, one gray). And yes, the white one was leaking worse than the gray (and it's newer). The caps on the 275 were leaking as well.

[poljana]

Anyone have a link to buy the sil pads. I have no idea how to navigate that site.

http://search.digikey.com/us/en/cat/fan ... sil%20pads

[JayGold]

Anyone have a link to buy the sil pads. I have no idea how to navigate that site.

http://search.digikey.com/us/en/cat/fan ... sil%20pads

Does anyone have an answer/specs to this for replacing the pads on MS amps?

[nico boom]

I have supplied a number of members with the correct silpads. Seems these are hard to come by, I buy them at a local shop over here where they have them made for me by the 100pcs.
PM me if I can be of assistance.

[jason2323]

Who makes and part# of the power supply that you are using to test your amp with?

[nico boom]

Who makes and part# of the power supply that you are using to test your amp with?

It my be me, but I do not understand your question, nor do I see any relevance to this thread.
Nico

[mhyde71]

hey nico buddy- i could use some sils if you got chance...ill cover whatever expense and stuff...jlmk...
need a bunch for a 2500, and perhaps a 44 and stuff. would like a bunch...so jlmk how much! thx mang!

[nico boom]

SURE THING Matt!
Howmany do you actually need, I order them by the 100 pcs. every time I go over to that shop.
LMK bro and I'll take care of it.
Nico

[JayGold]

Replacing caps on a MS2125, the transistors will not pop from the sink with the OP's technique....any alternative suggestions?

[Mr. Wild]

Remove the screws, then select a drill bit (4mm or so) that fits perfectly into the transistor hole. Push the flat end of the drill bit all the way into the hole (PG p0rn:-)) and use it as a lever to gently bend the transistor off the heatsink.

[nico boom]

Remove the screws, then select a drill bit (4mm or so) that fits perfectly into the transistor hole. Push the flat end of the drill bit all the way into the hole (PG p0rn:-)) and use it as a lever to gently bend the transistor off the heatsink.

And prior to that, heat the sink with a hair-dryer to a normal operating temperature. This will soften the silpads a bit so they will come off more easily.
Be sure to use both hands when applying pressure to the drill, resting your palms on the sink. You don't want to bend the leads more than needed, otherwise you're likely to do so when the transistor comes loose all of a sudden. [and they do].
Also use; PATIENCE as sometimes you'll have to apply pressure for more than a few minutes before one comes loose.
Good luck.
Nico

[JayGold]

Remove the screws, then select a drill bit (4mm or so) that fits perfectly into the transistor hole. Push the flat end of the drill bit all the way into the hole (PG p0rn:-)) and use it as a lever to gently bend the transistor off the heatsink.

And prior to that, heat the sink with a hair-dryer to a normal operating temperature. This will soften the silpads a bit so they will come off more easily.
Be sure to use both hands when applying pressure to the drill, resting your palms on the sink. You don't want to bend the leads more than needed, otherwise you're likely to do so when the transistor comes loose all of a sudden. [and they do].
Also use; PATIENCE as sometimes you'll have to apply pressure for more than a few minutes before one comes loose.
Good luck.
Nico

Nico, thanks for the input...this is what it took to release them from the sink. Soon I'll be using the sil-pads you sent me, just have to take care of some other tid-bits first on the board (posted that in a new thread).

[zeropoint0.5]

@ Nico, you've got pm about the silpads.....thank you....

[luigi66]

I don't use paste with sil-pads. The pads are designed to make full contact on their own with sufficient pressure. Besides, paste can be messy (I have had it all over me and amps I have worked on before). Pads alone may not conduct heat as well as pads with paste, but the MS amps which use pads are not all that demanding on the parts anyway. If you look at the MS2250 though, things are different. This amp uses no pads and has the devices mounded directly to the heatsink with paste, for the best possible heat transfer. The whole heatsink is anodized to keep the parts isolated.

The pad you removed on your MS275 is not a big deal. However the via next to it is. That looks damaged to me. If you don't make 100% certain the top and bottom are electrically connected when you solder the cap in, your amp will likely fry when you turn it on. When I replace these caps I make note of an area near the cap I can probe with my DMM once the cap is in place and I check conductivity from the bottom of the cap to the board top side. In your photo you can probe the screw to the bottom of the cap.

Also for anyone else reading, if your rail caps (the big ones) don't look physically bad, don't replace them. I have yet to find one leaking. The smaller 2,200uF caps are the problem. I have seen many thermally damaged rail caps though, and in this case it looks better if you replace them.

I have a question then the problems are always on the capacitors small and not big ones that cannot be replaced right?

[nico boom]

The lifespan of a chemical product like a capacitor is limited.
That is why I choose to also replace the railcaps [big ones] when recapping; taking a MS amp apart is not something you want to do more often than needed and if you love that amp, you want to service it thoroughly.
Replacing the railcaps and silpads along with the inputcaps does just that. You also don't mount the board back in the sink with stains on it, do you?
Although the railcaps can look physically O.K , you don't know how the inside has changed over the years.
If you look at what most manufacturers say about the lifespan of their capacitors [between 6- 8 years], you might agree with me.
I have seen caps fail on motherboards inside computers that were only 6-7 years old..... making a mess of the whole interior.
My opinion; DON'T BE SORRY, BE SAFE.
Nico

[luigi66]

The lifespan of a chemical product like a capacitor is limited.
That is why I choose to also replace the railcaps [big ones] when recapping; taking a MS amp apart is not something you want to do more often than needed and if you love that amp, you want to service it thoroughly.
Replacing the railcaps and silpads along with the inputcaps does just that. You also don't mount the board back in the sink with stains on it, do you?
Although the railcaps can look physically O.K , you don't know how the inside has changed over the years.
If you look at what most manufacturers say about the lifespan of their capacitors [between 6- 8 years], you might agree with me.
I have seen caps fail on motherboards inside computers that were only 6-7 years old..... making a mess of the whole interior.
My opinion; DON'T BE SORRY, BE SAFE.
Nico

Thanks for the help I realized then that to do a great job you have to replace all the capacitors and those small ones that just great?
question:
I saw on the site of the capacitors Digikey USA precisely this series:

Nichicon UHE1C562MHD6

but all they are blacks for those wanting to take a series of big blue like the original where can I see?
Thanks to everyone for the help
Louis

[luigi66]

Question:
I saw the Nichicon capacitors but they are all blacks, I do not mind the small ones are fine, but wanting to find the biggest blue capacitors where can I see?
Thank you for your invaluable help
Louis

[nico boom]

JOERG; you searched for the blue caps a while back, did you find a source for them?
The ones I always used are black, you will loose the "original look" but gain reliability.

[luigi66]

JOERG; you searched for the blue caps a while back, did you find a source for them?
The ones I always used are black, you will loose the "original look" but gain reliability.

In fact, losing the original look me a little annoyance that's true.
I saw that Philips was producing capacitors blue and Bc components made ​​of blue but I do not know if back in the parameters, but I have yet to see, however, here is the address if you want to watch:
http://www.vishay.com/company/brands/bccomponents/

Question : whether to use a capacitor with a larger output volt what happens? 63volt vs 50 volt
Greetings Luigi

[luigi66]

Here is the search engine if you want to watch:

http://www.vishay.com/capacitors/selection-tool/

Greetings Luigi