Marantz MA-700...Popping sounds?

Three Legs · 7th March 2009, 03:05 PM

In the last few days I've noticed one of my MA-700 monoblocs has started to make my speakers pop! I've done the eliminatory procedures just to verify that it is the offending mono, which it is.
What I can say is when I received(at the mercy of couriers) the (pair)MA-700 monoblocs with slightly bent speaker inputs. I decided at the time, as long as the amp worked ok I'd not mess with it. I did have slight reservations about one of the boards at the rear appeared to taking a little strain due to the inputs being forced upon it.
Because the pops were now getting more prominent, I decided last night to open the amp up to investigate. I figured if I could release the pressure on the strained board and hence get the speaker terminals straight again, it might decide to work properly again. However, when looking over the rest of the amp, particularly the caps I noticed the cap joint at the base to be flaky....
I'm now wondering if this may be the cause?

Can anyone offer any suggestions or advice for a newbie?

Thanks in advance.

unclejed613 · 7th March 2009, 11:48 PM

replace the electrolytic. the popping could be because of an intermittant connection inside the cap, especially if one of the leads got pulled on by the mechanical damage in the amp. the plates in the caps are pieces of porous aluminum foil, very easily torn or broken by stress on the leads.

Three Legs · 8th March 2009, 09:47 AM

Thanks for the reply unclejed613....Is there anyone I could contact to undertake the repair, hence someone like burnedfingers. I know he has repaired MA-500's, so I'm guess he'd know how to repair the MA-700. I can't contact him, because I'm a newbie with no privileges....

Could anyone do me a favour and contact burnedfingers to let him know about my thread.

Thanks in advance.

Netlist · 8th March 2009, 09:48 AM

Quote:

Originally posted by Three Legs
... I'm a newbie with no privileges....

Not anymore.

/Hugo

Three Legs · 8th March 2009, 12:17 PM

Quote:

Originally posted by Netlist

Not anymore.

/Hugo

Much appreciated Hugo...

Original Burnedfingers · 8th March 2009, 01:25 PM

Quote:

Could anyone do me a favour and contact burnedfingers to let him know about my thread.

You have given me much more credit than I deserve.

I haven't touched a MA700 yet because the shop were I work has probably only sold a dozen or so of them and nothing has come back in for repair yet. Unlike the MA500 I might add.

I will see if I can score a service manual for the MA700 if they are still available.

unclejed613 stated a good point. Replacing the caps is a good place to start on this series of product because as it would seem they have a higher than average failure rate.

Three Legs · 8th March 2009, 08:53 PM

A service manual would be greatly appreciated burnedfingers. I'll start with replacing the caps after I find the parts...
Where would I find such parts for the Marantz?

Thanks in advance.
Bit of a newbie here, but I'm more than willing to give it a go!

7th March 2009, 03:05 PM	#1
Three Legs diyAudio Member Join Date: Nov 2008	Marantz MA-700...Popping sounds? In the last few days I've noticed one of my MA-700 monoblocs has started to make my speakers pop! I've done the eliminatory procedures just to verify that it is the offending mono, which it is. What I can say is when I received(at the mercy of couriers) the (pair)MA-700 monoblocs with slightly bent speaker inputs. I decided at the time, as long as the amp worked ok I'd not mess with it. I did have slight reservations about one of the boards at the rear appeared to taking a little strain due to the inputs being forced upon it. Because the pops were now getting more prominent, I decided last night to open the amp up to investigate. I figured if I could release the pressure on the strained board and hence get the speaker terminals straight again, it might decide to work properly again. However, when looking over the rest of the amp, particularly the caps I noticed the cap joint at the base to be flaky.... I'm now wondering if this may be the cause? Can anyone offer any suggestions or advice for a newbie? Thanks in advance.

7th March 2009, 11:48 PM	#2
unclejed613 diyAudio Member Join Date: Dec 2006	replace the electrolytic. the popping could be because of an intermittant connection inside the cap, especially if one of the leads got pulled on by the mechanical damage in the amp. the plates in the caps are pieces of porous aluminum foil, very easily torn or broken by stress on the leads. __________________ Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net spammer trap: http://www1284177414881.v-dc.net/

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8th March 2009, 09:47 AM	#3
Three Legs diyAudio Member Join Date: Nov 2008	Thanks for the reply unclejed613....Is there anyone I could contact to undertake the repair, hence someone like burnedfingers. I know he has repaired MA-500's, so I'm guess he'd know how to repair the MA-700. I can't contact him, because I'm a newbie with no privileges.... Could anyone do me a favour and contact burnedfingers to let him know about my thread. Thanks in advance.

8th March 2009, 08:53 PM	#7
Three Legs diyAudio Member Join Date: Nov 2008	A service manual would be greatly appreciated burnedfingers. I'll start with replacing the caps after I find the parts... Where would I find such parts for the Marantz? Thanks in advance. Bit of a newbie here, but I'm more than willing to give it a go!

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