how to replace caps on ar3

[canman]

What are best steps to gain access to caps on ar3/

[DavidDru]

The AR3A restoration guide available here in the library has everything you will ever need.

You go in thru the woofer cavity.  Remove screws, remove some of the old sealant putty around the edges of the woofer (seems to help a little), pry it out being careful not to damage the wood around the edge.  A paint can opener is a handy often readily available tool that works well.

[canman]

So the AR3 and AR3a are the same?  I assume you are saying they are inside the box labeled Industrial Condenser Corp?d Industrial Condenser Corp?

[ra.ra]

Hi canman, the AR-3 and the AR-3a are definitely not the same. It appears that your crossover has two pots, two caps and one inductor, which seems to correlate with AR-3 schematic version C (serial nos. C19468 thru C70228), as shown in the AR-3a restoration manual. Your caps would be 24uF for the mid and 6uF for the tweeter, and yes, they are both located in that wax box underneath the coil. You can go to the effort to remove it, or you can simply leave it in place after snipping the green, blue and black wires which would be attached to new caps if you should decide to replace them.

Also, you will want to disassemble and inspect the potentiometers. Most likely they will show evidence of corrosion, and often these can be cleaned and revived, but sometimes they require replacement.  

[DavidDru]

like ra.ra says, they are not the same.  The guide is applicable though and it makes some references to some of the difference as you go.  As far as physical build etc, they are very much alike with the usual changes made over time.  Yes, drivers changed, crossover components sort of changed, but not so much that you can't figure it out.  Plus throw questions out here as you go as you are doing for clarification.

Also, look back at older 3 restoration threads here and you will find identical efforts including mine.   Many of us leave that wax cap box for old time sake.  Plus it holds the coil nicely.  Plenty of room to mount the new caps around it.  Some rather creative dudes have hidden the new caps inside that box which is cool.

Also as ra.ra. indicated, the damn pots are the usual buggers in all this.  Remove them, open them up and show us what they look like.

[canman]

Here are my pots...

[genek]

The wax box is the capacitor (actually, two of them). There are layers of conductive film and wax within it, rather than separate cans. This type of capacitor is no longer manufactured, so you replace it with two separate modern capacitors. Some people save the shell and put the new caps inside, but since you're going to seal the cabinet up there's really no point.

[JKent]

Hi Canman

Your pots definitely need cleaning but they're not too bad so they should be salvageable. See the section in the restoration guide, pp 13-16 re pots. Of course you could replace them with L-pads but the AR-3 has become so collectible (read pricey) it's best, IMHO, to keep them as original as possible.

-Kent

[canman]

Anyone have any photos of the inside of their AR-3 after they have installed replacement caps?  Trying to make sure I am wiring this correctly and completed photo or two would be greatly appreciated.

Thanks everyone!