The installed, new terminal cup.  (What I affectionately call "The Beovoxian Americanization.")

The phase links don't have a manufacturer or model number on them.  There is some kind of "P in a circle" logo on them.  Peerless?  The serial numbers on them are 760120 and 760324.  They appear to be the same.

Tonight I epoxied the phase links per Martin's direction.  I also tried a mock-up of the crossover network.  I think it'll work.  I'm going to begin giving the crossovers a go tomorrow.

One epoxied phase link:

So Martin (or anyone), what happens again to these phase links?  The magnet "falls into" the spider during shipping?  There were some P45's on Ebay that looked fantastic but I was reluctant to bid based on what I've read on the site.

The pole piece sits inside the coil and is glued to the inside of the end piece (3mm thick rear cover plate).
The end piece is glued to one end of the magnet.
The other end of the magnet is glued to the metal chassis (basket) of the driver.
The glue hardens with age and becomes brittle.
When the speaker is shipped or moved about with less than utmost care, the magnet losens
and due to the magnetic forces the center piece will be sucked to one side (taking the magnet with it),
squeezing the coil between the center piece and the driver chassis.
This will block the coil from moving and the cone will feel like welded in place.
The move is only about a millimeter or so, not enough to really stand out, and many owners believe that the coil
has been cooked by an overload. The magnetic forces are very strong so it is not possible to push the magnet
back to center the pole piece, it will keep snapping to the side.

To prevent the magnet from shifting, I've found that the best thing is to place a bead of epoxy
glue around the magnet where it meets with the chassis.

Note that the magnet in most cases (and indeed on most Peerless drivers like this), sits on
an apprx. 3mm thick extension flange that is welded to the chassis.

From what I can see in the photos, it seems Rich actually glued this flange and chassis rather than the flange and magnet.
Place the driver magnet down. Put a bead of glue around the top of the magnet where it meets with the chassis
or in this case, the flange.

So far, affected drivers include these M70 "phase link"-drivers, P45 and P50 woofers and S45 (type 6302 and 6312) woofers
and speakers in the later Beolit portable models.
I am working on a solution to realign the magnet, hopefully a repair solution can be found.

Martin

Dillen:

From what I can see in the photos, it seems Rich actually glued this flange and chassis rather than the flange and magnet.
Place the driver magnet down. Put a bead of glue around the top of the magnet where it meets with the chassis
or in this case, the flange.

 

Martin

And that is why we post pictures as we go!  Will repair the repair tonight after work and begin working on the crossovers.

Didn't do the repair on the phase links because I was just too interested in starting the crossovers!

But first, quiz time!

What can you make with the following?

Here's a hint:

Is the suspense killing you?

Well, the answer was "a crossover network"!  But of course you knew that.

I used (and reused and reused again) my MAD TETRIS SKILLZ trying to figure out how to layout the crossover network for the M70 with these gigantic Solen capacitors.  The first key was realizing I had to split the crossover into two boards:  one for the phase link and woofer, and one for the two domes.  The second key was having the revelation that I could "stand up" some of the Solen caps so they took up less surface area on the board.

Here's the woofer/phase link board with the Solen capacitors and reused inductors hot-glued to the board.

Here's the top of the fully soldered woofer and phase link board, with resistors added.  If you look closely you'll see two terminals glued to capacitors.  That's where the "hot" leads to the drivers get soldered.

And here's the bottom, where just a bit of soldering was needed for the final connections.  I didn't snip any wires down on any of the pieces in case I made a mistake or wanted to rearrange or whatever.

My first thought was to mount this board on the removable speaker back in the approximate location shown below. But as I was typing this very post, I thought maybe it would be a better idea to mount it on the bottom of the speaker box.  I'll have to think on that a bit.

I anticipate mounting the domes crossover board in the original crossover location (the wooden bar toward the top of the box).

Love those crossovers Rich! I can see why you were so excited!

Evan:

Love those crossovers Rich! I can see why you were so excited!

Thanks, Evan.  Tonight I came home and ate Irish food cooked by my Irish-American wife and then got back to the M70s. 

But before describing that:  Happy St. Patrick's Day for those who celebrate such things (you know, people like my wife)!  I raise my Kentucky bourbon glass in your general direction!

Since it's highly likely I will be listening to the M70s this weekend, I first applied the two-part epoxy to (hopefully) the right place on the phase links.

Then I got out my MAD TETRIS SKILLZ again and laid out the other half of the crossover network (for the two domes).  Here is the end result.

If you look in the lower right of the picture, you may see a lone wire sticking up next to R10.  That's where the hot side of the tweeter gets hooked up.

Though it may not look like it, this half had just as many layout challenges as the other half.  The other half was basically just real estate - too much space needed.  But the circuit itself was relatively uncomplicated with just one major junction of "way-too-many-parts."

This half had a goofier circuit.  I'm still not exactly pleased with the result, but you can only sit around moving stuff around before you have to get down to hot-gluing and soldering.

This half will be installed where the original full crossover network was originally hung.  There's plenty of room on that cross bar.

Tomorrow night's goal will be to get the caps and coils glued down on the circuit boards for both halves of the second speaker.  I must resist the temptation of mounting the crossovers and getting down to some listening of the first speaker - I need to use the completed crossovers as templates for the ones I have to do next.

I don't see any reason why I won't be listening to a stereo pair by Sunday night.  I'll still need more work on the finish, plus there are no grills (frets) as yet, but at least I'll be listening.  Because in the end, it's all about listening.

Nice work with those filters.
I can't help thinking that the large caps on the woofer board will eventually break free from the board or snap their leads
from the unavoidable vibrations in the cabinet, not helped much by their position, sticking out horizontally
with not much support of their quite respectable weight.
If you could find a place for this board at the bottom of the cabinet, I'm sure that would be much better in that the
caps would then stand on their ends.

Martin

I think what I'm going to end up doing is putting the woofer/phase link half on the bottom of the cabinet lying horizontally, and the dome half lying horizontally on the phase link subenclosure.  I'll have to rig something up and play with it a bit for the domes, but Martin's right - don't want to lose any of these huge Solen capacitors.

The woofer/phase link half does fit in the bottom of the cabinet.  I got the second one done tonight so I went ahead and checked fit by remounting one of the woofers.  The board is sitting on 3 blocks of wood about 20 mm x 30 mm x 3 mm.  I'll glue the blocks to the cabinet tonight then mount the board to the block with screws.

I also played with placement of the domes half.  I think I'm going to have to go with my original plan to place them on the cross bar (original crossover location).

Its easy to come with ideas afterwoods, sorry, its very nice work indeed, but making the woofer filter board a little longer you can lay the big caps down and have space to spare under the woofer, and after gluing being shure that they will stay there.

As a mechaniac i admire your work and will try to compete with you in my future objects. 

Looks fine, that's a much better position.

Martin

I agree - puting the board on the wood bracing strut would seem logical. It probably should avoid touching the container for the phase link unit. Lovely job - you have used big capacitors! You almost need an external cross over! Tim replaced the capacitors in my M100s but I think he used smaller ones than those originally fitted!

Hey what's that sitting in the corner?  Why, that's a reassembled M70!

One down, one to go.

Here's the status of the other speaker.  Still have to:

1. Solder some driver wires to the woofer/phase link board then mount the board in the cabinet
   
2. Connect the terminal cup to the boards
3. Regasket the back and the drivers (except the midrange - the midrange mounts from the inside and its gasket was still in fine shape)
4. Mount the back
5. Solder the driver leads
6. Put new damping material in the main cabinet (I'm reusing the phase link subenclosure damping material)
7. Mount the drivers
8. LISTEN!!!

I'm taking a bit of a break.  I was at it pretty much for 5 hours straight from the morning into the afternoon.  The wife and kids are now all out, so it might be quicker going with the second speaker.

There will be listening tonight!  Tomorrow I think I'll bring all 3 of my projects - M70, S45-2, S40 - into the same room and do some comparison listening.

Didn't take many pictures today.  Just pressing through to the finish.  I did, however, pause to take a shot of applying the new gasket material.  Thought there might be some interest in this for possible other applications.