Need to recap 20-year-old Monitor Audio 703 PMCs?

[alife]

I am a novice and am looking for advice on whether the caps in my 20-year-old Monitor Audio speakers need to be replaced. The speakers have sat in storage for three 2-year-long stints. My only sense of a change in their sound is that the highs seem to have mellowed, but that could just be my hearing!

I could find no information about the crossovers, other than mention in one review that "the crossover network involves a measure of equalisation to 'peak up' the main driver output just prior to the (highish) 4kHz electrical crossover point."

Examining the crossover (see picture at link below) it looks like there are two (yellow-coloured) caps. Both are Expotus brand, which from browsing this forum I understand are metalized film caps. One is marked "3.3K 100V", the other is marked "6.0K 100V".

Is my understanding correct that metalized films caps are unlikely to deteriorate and would not merit replacing?

The white component in the picture looks like a resistor. I can't make out the full brand name but the name ends in "opride" and the marking says "7W 3.3 ohm J".

Dropbox - MA 703 PMC crossover.jpg

Your advice would be much appreciated. Thank you.

 

[chops]

Really no reason to replace anything in that crossover unless you want to try upgrading caps, inductors and resistors just for the fun of it. If you choose wisely on caps, etc, etc, you can improve the performance of the system. If you don't you can throw things way off.

 

[system7]

I agree. No point in changing anything. Those film caps won't have deteriorated. Maybe the ferrofluid on the tweeter could be replaced. It tends to dry up and reduce output on tweeter.

Best guess on a 3.5khZ crossover, for what appears to be a 8 ohm 6" plus 1" speaker.

 

[nannoo]

100% agree, leave them alone. They're fine and covered in glue. Anything you do is more likely to do damage than good.

 

[alife]

chops, system7, and nannoo, thanks very much for your advice. Glad to hear that I should leave well enough alone. Wasn't really looking forward to fiddling with the crossover, given the risk of messing up the sound that I like.

System7, I have done some reading on replacing ferrofluid. Looks doable but again there is some risk of ruining the tweeters. Any sense of the odds that the ferrofluid has dried out by now, or how to assess whether it has? (I read your thread on restoring MA R300/MDs with interest.)

Thanks again.

 

[system7]

If you wreck the tweeters while inspecting them, you are just plain unsuited to engineering. Though we've all had our disasters with mysteriously constructed components.

These look like the voicecoil lifts off when you undo the 4 inner screws. Lift the coil up vertically. Hopefully the tinsel wires come up at the same time, though some designs need unsoldering first.

Sonitus Audio Ferro Fluid (ferrofluid) for Speakers and Compression Drivers 0.5ml PS4.99 IN STOCK (1 Feb 2018)

The above is the cheaper clip on type. Clean out the old gunge with a blotter and maybe a solvent like WD40 lubricating spray. Add about a 1/5 of the 0.5mL in the syringe. It's not critical. It's like oiling your bike chain.