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Replacing Caps????
Posted: Wed Oct 06, 2010 10:30 am
by Blad09
I keep seeing posts about replacing caps in an amp. Why is this done? How do you know when it should be done? I don't plan on trying it, but I'm interested to know how and why. Thanks for any replies!!
Posted: Wed Oct 06, 2010 10:45 am
by marko
because the caps leak fluid and short out then make a big mess of your board.. if your lucky the amp is fixable. the caps in question are the 2200uf 105c 16v items in the power supply, all M,MS,MPS, ZPA and ZX amps will need doing to be on the safe side as some of these amps are knocking on for 20 years old and caps don't last for ever!
there's plenty of tutorials on here about the subject
have a look here as an example..
http://phoenixphorum.com/my-m50-from-cr ... t7156.html
Posted: Wed Oct 06, 2010 2:28 pm
by ttocs
they also have a tendency to explode after they start leaking and you would be suprised what kind of "POP" one of those little buggers can make. When that happens it often takes the board with it.
10 yrs is the general rule when they need to replace them.
Posted: Wed Oct 06, 2010 3:28 pm
by Blad09
Huh, maybe I will be doing some. I posted about an Alpine amp that I got a while ago, anyways I hooked it up and was pretty disappointed with the output (it barely even pushed my subs, but it was workin) so I opened it up to find a blown trace that had been replaced with a piece of copper wire soldered to the breaks. I checked for continuity...nothing, but if I hold down on the piece of wire it is continuous. Will this work as a fix? Also the amp is from '97ish with original caps should I be replacing them? It's an MRV-1000
Posted: Wed Oct 06, 2010 3:37 pm
by tonym
Blad09 wrote:Huh, maybe I will be doing some. I posted about an Alpine amp that I got a while ago, anyways I hooked it up and was pretty disappointed with the output (it barely even pushed my subs, but it was workin) so I opened it up to find a blown trace that had been replaced with a piece of copper wire soldered to the breaks. I checked for continuity...nothing, but if I hold down on the piece of wire it is continuous. Will this work as a fix? Also the amp is from '97ish with original caps should I be replacing them? It's an MRV-1000
easy fix.....
get a PG amp.....
Posted: Wed Oct 06, 2010 3:45 pm
by Blad09
Yea the Phoenix amps look f*%#@ tough as nails inside I just can't afford them I paid $40 for the alpine and it's the biggest amp I have so I would like to use it. It matches my subs good if I can get it running to its full potential. So do you think its worth my while or not?
Posted: Wed Oct 06, 2010 4:01 pm
by THUMP-LUMP
Curious......Would the caps need to be replaced in an old M series amp that has never seen power? I have a new M25 and a M50 that are new in the box.
Posted: Wed Oct 06, 2010 4:07 pm
by ttocs
absolutely any M series still sporting its stock caps is due for a replacement before any serious use....
Like I said after about 10 yrs you need to start planning for and certainly keeping an eye out for it if you can take it apart and check it. I currently have the caps needed to replace the large bank of caps in my octane LE and just need to take the time to pull it out of the install it is currently in use in my truck
Posted: Wed Oct 06, 2010 4:46 pm
by Eric D
ttocs wrote:absolutely any M series still sporting its stock caps is due for a replacement before any serious use....
Like I said after about 10 yrs you need to start planning for and certainly keeping an eye out for it if you can take it apart and check it. I currently have the caps needed to replace the large bank of caps in my octane LE and just need to take the time to pull it out of the install it is currently in use in my truck
Not just serious use, ANY use! I took a nice M series amp out of storage on my shelf, hooked it up on my test bench and it started arcing and began to burn. Luckily for me I pulled the plug before it got out of hand, and I was running it through a current limiter. If I had put it in my car, it would have burned up as soon as I put the fuse in under the hood. Turning the amp on has nothing to do with it, the input caps can burn at any time.

Posted: Wed Oct 06, 2010 6:37 pm
by THUMP-LUMP
So before I use either of those for the first time, they both will need new caps?
Posted: Wed Oct 06, 2010 7:21 pm
by ttocs
they may or may not but it is safer/cheaper to plan ahead and do it. It is one of the few pieces of preventative maint an amp needs.
Posted: Wed Oct 06, 2010 7:37 pm
by THUMP-LUMP
No problem. I'll do it before I do anything else with them. I see an order to Digikey in my future.