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Re Do Black Widow 18

#21
It's kind of tough to get off, especially if the foam is sticky in the gap, but it need to come off straight. You might rotate the magnet gently to break the joint between the basket and the magnet.
 
#22
borgward said:
Tanks for the encouragement guys. I was going to leave it in the cab until I found a replacement or repair. Things seem to get lost after being taken apart if left un assembled. Well here goes...............I removed the speaker from the cab. Looking at the back side I see a wire screen in the hole in the center of the magnet. I can see something loose down in there that looks like old dried out foam.
Any words of wisdom before I disassemble the speaker? There are three bolts back there. Do I need to index anything?
Click to expand...

No words of wisdom, it'll be fine to remove the basket which will be 3 bolts. Pull the magnet off and check the thin gap of the magnet. Even if it looks clear I would clean it. Check the basket for any loose foam or anything. Once that is done, put it back together and install. Back to your cab. I have an 1810 too and have done this same procedure but with the two 10" scorpions on the top. I cleaned them and got rid of the buzz. Good as new for a few years now.
 
#23
Rocker47 said:
No words of wisdom, it'll be fine to remove the basket which will be 3 bolts. Pull the magnet off and check the thin gap of the magnet. Even if it looks clear I would clean it. Check the basket for any loose foam or anything. Once that is done, put it back together and install. Back to your cab. I have an 1810 too and have done this same procedure but with the two 10" scorpions on the top. I cleaned them and got rid of the buzz. Good as new for a few years now.
Click to expand...

I have the speaker apart now. I placed the magnet over clean paper. Lots of dirty particles were left after I picked the magnet up. Under the wire screen there is a dark ring about .25 to .3125 inch wide. I assume that's the aforementioned foam. Should I dig that out. or leave be? See .png I am sending.
 

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#24
borgward said:
I have the speaker apart now. I placed the magnet over clean paper. Lots of dirty particles were left after I picked the magnet up. Under the wire screen there is a dark ring about .25 to .3125 inch wide. I assume that's the aforementioned foam. Should I dig that out. or leave be? See .png I am sending.
Click to expand...


If that's the part of the magnet that the basket sits on definitely clean it out. It's hard to see what you are describing from your picture. Sounds like the foam got old and dry. Clean out all of the junk in the magnet. Also, check YouTube for videos as there must be someone showing how to do it.
 
#25
I blew the image up. Looks like the foam was quite thin and sandwiched between the inner and outer section of the magnet. Looks like the wide dark area is where it melted down the side of that hole. Maybe I should put some foam air cleaner material on the backside (outside) of the magnet when I am done. There is an incredible amount of dust inside the cabinet. I am going to leave it be. A friend left a photo print enlarger with me for a year. Really was dusty, so I cleaned it up. That was a mistake. Found out I should have left it alone. Somehow the dust acted like a dust magnet that kept new dust from getting on my negatives.
 

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#31
More problems. I was running a plastic toothpick inside the annular ring the coil goes into. The pick was loose in some areas and tight in others indicating that the center part of the magnet is off center. Looks like that center part is a separate part either pressed in or held by magnetic force. There are 3 slots in the outer part of the magnet 120 degrees apart. Looks like I could manipulate the inner parts position and check with feeler gauge. Second problem is that I can see tiny metal particles in that annular ring. Probably from me scraping the gunk out of the center hole. I am getting a lot of it out with the sticky side of tape. Is that center part of the magnet removable? Looks like it is. May remove after further consultation so I can be sure there are no more metal particles in there.

I do not see any damage, loss of insulation to the coils on the basket assy.
 
#32
No, it should not be removable. If you do manage to loosen the magnet, it would stick hard and fast to the return plate and you are dead in the water.

Are you sure it's not hardened foam causing the sticking of the pick in the gap? Did you clean the gap carefully with lacquer thinner. Soak business cards or card stock in thinner and work around the gap.
 
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#33
Nothing but shiny metal now. M might reassemble and feel for any binding before applying power. I did index the basket assy to the magnet before taking apart just to be safe. The inner wall of the outer magnet goes straight down. The inner part's wall goes straight down about a 1/4" and then below that is a cavity. I am guessing those slots in the outer part are for aligning the center part. Won't try if the basket assy moves freely.
 
#34
The undercutting of the pole piece is part of the design, it alters the shape of the magnetic field within the gap.

I don't know what the 3 slots are for, I doubt it has anything to do with the centering, but you never know. Other manufacturers have managed to center pole pieces without the slots. JBL used some interesting pole piece geometries over the years, primarily to help vent the gap which can help cooling and reduce turbulence noise or whistling.
 
#35
Success! Finally found double sided tape thin enough to get into the magnets annular ring. I left the ring the way it was. The armature was able to freely move. The speaker functions well. I think it would be prudent to get another 4 ohm speaker while I can for backup. I looked at the youtube videos about rebuilding these speakers. They showed placing the magnet over the basket on reassembly. That magnet felt too heavy for a precision placement. I was afraid I would mis align it and crush the armature. I placed the magnet on the table and it was much easier to align the basket onto it. It would be good to get long bolts and cut the heads off so they could be used as dowels to guide the basket and magnet together. Especially if you have the basket on the table and are placing the magnet down on it.

I then took a look at the two 10's. Sure enough, the foam filter on them had broken loose. I found both of the foam filters in the bottom of that compartment. They did not feel dried out like on the 18. The 10" speakers appear to have replacement baskets. Looks like Peavey construction, but I see no Peavey anywhere on them. The label:

S10825
96000273
REPL BSKT
00013870
STOCK/SALES
00013770
71200630

I think these are 8 ohm speakers paired together so they work together for 4 ohms. Is this the way it should be. They do work well.

I get 5 ohms for the 18, and 11 ohm for the 10's with my cheap Radio Shack VOM. Will see if I can get my hands an a better meter.
 
#36
About the two 10's. They are scorpions? I have a read about people blowing them. Looks like they were blown before I ever got it. I have never bi-amped it, but I have run the Bass 400 really LOUD. I have never had trouble with them. I suppose that head is just not powerful enough to hurt them. If I ever did bi-amp that cab, what is the max power the scorpions will handle? What's the most power the 18" BW can handle?

Like anyone would need to play that loud! We lived in a brand new tight energy efficient house when I got that 1810. I saw the caution "Can damage your hearing" yeah yeah yeah. I plugged into that sucker and cranked it up. After less that a minutes it felt like the atmospheric pressure went up. Felt like a big set of hands were squeezing my head. I became a believer in that warning label!
 

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