JBL L150A - Crossover mounting board fastener size?

[DerekTheGreat]

Hello everyone,

Quick question, WTF is the fastener size of the black screws which go through the back of the cabinet and hold the crossover to the cabinet? I'm not sure if they're metric or SAE, but I'm trying to replace them with some slightly longer fasteners and also need the size to get the correct T nut to hold the new crossovers in that I ordered from SpeakerChef on eBay. Kind of pissed about the crossovers, didn't realize that I'd need to have a woodshop out in the garage to get them done semi right.. So if anyone knows, that would be awesome, thanks. The original fasteners seem to be about 1.25" in length, have a head that measures ~5/16th an inch with a shaft diameter of about 1/8th of an inch, fine thread. They might be metric..

[JeffW]

I think JBL was pretty fond of 10-32, you might try a 10-32 and see if that's what you have.

[DerekTheGreat]

Thanks Jeff. I can't seem to find any that have the same head diameter as the originals so looks like I have to use them. But, at least now I know what T nuts to buy, thanks to you.

[rdgrimes]

Just to keep you on your toes, they made quite a few variations of that crossover board and attachments over the years for the L96, L112 and L150A. Some plastic, some Masonite, some screws and some machine bolts. But you're looking for a bevel-head that sits flush to the rear baffle surface. I think I've found pretty much all of those bolts and T-nuts at Lowe's. Same as they used on the drivers.

[DerekTheGreat]

Yeah, I think mine are later models. I've never, ever seen a pair of early JBL's with consecutive serial numbers, only close. However, these are consecutive and have "A" at the end of them, whatever that means. Crossover networks have ~1/4 fiberboard with nicely integrated t nuts and plastic widgets which the blue crossover board clips into. Was a piece of rotten foam between them.

Anyhoo, I think I'll just reuse the factory fasteners but like you said, take a trip up to Lowe's tonight and see what I can't find to match up. Going to make my own board and then mount the crossover board I got from SpeakerChef to that. Should be pretty cool when it's done. I bought separate three way toggle switches for the -2|0|+2 positions for the mid and tweeter and it's set up for passive bi-amping. Just got it put it all together.