M-Audio AV40 Dead Monitors Revival (capacitor replacement)

I was recently given a pair of dead M-Audio AV40 near field monitors.  These little speakers are great!  However, I was puzzled as to how exactly they had failed.  After some googling I found that a few of the capacitors used on these have a tendency to go bad and leak.  I decided to open up the case and sure enough: I found the capactior were bulging and had a chemical leak at the top.  I removed the capactitors and ordered them from mouser.com as follows:

EEU-HD1E221
Panasonic Aluminum Electrolytic Capacitors - Leaded
US HTS:8532220040 ECCN:EAR99 COO:JP     2     2
RoHS: Compliant1
667-EEU-HD1V472
MFG Part No:EEU-HD1V472

EEU-HD1V472
Panasonic Aluminum Electrolytic Capacitors - Leaded
US HTS:8532220040 ECCN:EAR99 COO:JP     2     2
RoHS: Compliant1
688-SKHHAK
MFG Part No:SKHHAKA010

The board shows the charges +/- so this helps when installing the replacements.

I used a solder remover and even though the capacitors were glued, I was able to just pull/tilt them off once the solder had been completely removed.

The only problem I encountered with this fix is that a small circuit board that was glued to the inside of the case detached and I wasn't able to reattach it.  Also, the amp heat sink might have been shorting with the speaker when I closed the case and tightened the screws.  The problem became worse when I noticed that even without tightening the screws, the short would happen when I would apply pressure to plug in the power cable. To fix this I applied a small amount of silicon around the case where the screws go so that It would add some space so the the speaker wouldn't short with the heat sink.

Well that was that--now go out and revive some gear by replacing capacitors!

tags: 
audio production, gear

Comments

Submitted by Julio Manzanarez (not verified) on
Comment: 
Hey, can I ask you a question, I'm currently repairing my brother's M-audio AV40, but the transformer died, I haven't been able to know the voltage output from the transformer, If anyone knows the voltage across the red wires, or from GND to a red wire, I would be glad to know.

Submitted by admin on
Comment: 

IDK, sorry!

Submitted by Mark (not verified) on
Comment: 
Late response but for the record...There is a great YouTube video where the guy uses a multimeter to measure the volts across the red wires. Just search YouTube for AV40 repair. He replaced several components including the transformer. Worth watching if you have trouble with the AV40’s.

Submitted by Joe70 (not verified) on
Comment: 
Would these capacitors have any effect on sound quality?

Submitted by Rob Simpson (not verified) on
Comment: 
I had to replace these caps a while back. After about 8 years with the new caps, I notice one of the 4700uF caps was starting to bulge. After some investigation, it appears the back-emf you get when you switch the speakers off is enough to push the voltage over the limit (and also gives a loud 'pop'). It's simple to fix by connecting a supression cap across the transformer input. I used a 0.33uF 275VAC cap (one of the yellow rectangular caps you get in fluorescent lights). No problems since.

Submitted by Axel (not verified) on
Comment: 
I have a set of AV40s and the same capacitor heats up blows whenever they were powered on for too long (12-18h). would it be possible to replace the capacitor with a longer lasting, different capacity/voltage one?

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