ALTEC 19 Crossover problems (Could this be the Rivets?) FIXED!!

[daveyh]

I have set of original ALTEC 19 crossovers that I have rebuilt. By rebuilt I mean new L-Pads, ceramic resistors and new Solen capacitors. I have also hammered the rivets and star soldered the ground connections. I have had the woofers professionally re-coned and installed a new diaphragm in the driver.

Here is the problem:

The speaker plays fine with the crossover out and unsecured from the wood case. When I try to screw it in place using one of the four attaching screws to the wood case I get no sound or distorted sound. A little pressure on the plate will cause the speaker sound the come back?? I have checked the other crossover and all the connections are the same.

Does this sound like a ground rivet not secured?

Should I use a drill and use sheet metal screws to secure it and get better contact?

Anyone have any suggestions? This is making be CRAZY!!

 

[bowtie427ss]

If you have done the ground by-pass mod, the rivets don't matter, they're by-passed.

 

[turboyam]

You should post pictures of those.

 

[toddalin]

I have set of original ALTEC 19 crossovers that I have rebuilt. By rebuilt I mean new L-Pads, ceramic resistors and new Solen capacitors. I have also hammered the rivets and star soldered the ground connections. I have had the woofers professionally re-coned and installed a new diaphragm in the driver.

Here is the problem:

The speaker plays fine with the crossover out and unsecured from the wood case. When I try to screw it in place using one of the four attaching screws to the wood case I get no sound or distorted sound. A little pressure on the plate will cause the speaker sound the come back?? I have checked the other crossover and all the connections are the same.

Does this sound like a ground rivet not secured?

Should I use a drill and use sheet metal screws to secure it and get better contact?

Anyone have any suggestions? This is making be CRAZY!!

If there is a circuit board, check for cracks in the traces and (even if not), check for poor solder joints at all points, including input terminals. It could be that you broke a trace or "fractured" a solder joint with your hammering and when you press on it, you push it back together momentarily.

 

[daveyh]

Before the ground bypass

 

[turboyam]

I would re-flow all solder joints (some are not so great). Also check for a capacitor broken lead wire.

 

[EarlK]

Hey Dave,

I was looking at your ( before ground bypass ) pics and think you might want to ( double check + ) compare all your wiring changes to someone who's done it all successfully.

There are a bunch of pics ( over at LHF ) where Altec Best walks a poster through the bypass wiring protocol ( among other things ) .




AB ( John ) over at LHF ( in M19 talk )

 

[toddalin]

Personally, I would not trust the rivets and would solder jumper wires between all riveted ground connections.

 

[daveyh]

UPDATE: I found the problem. These woofers both were professionally re-coned and had been done for about a week. One of the woofers went bad. I only found it using a 1950 tube HP CD 2000 signal generator in very low, I mean low volume. You could then hear it. I tried other signal generators and I could not hear it, Had it re-coned and all is good!