is this 2440 corroded or in good condition?

[frank23]

hi,

I wondered if anyone could tell me whether the small bolts inside this 2440 are corroded and if this is normal for their age, or that they should be in better condition.

It is said to have a new titanium diaphragm, I have no comparison at home {I only have 2420's]. Does this look like an original JBL diaphragm?

Thanks, Frank

[norealtalent]

Diaphragm definitely looks like titanium and could very well be an authentic JBL. I would guess by looking that it is but I am sure someone here will be able to give you a definitive answer. The corrosion on the screw heads doesn't bother me in the least. All drivers have a way of building heat in the acoustic chamber which creates environmental changes beyond control. Even in the best of atomospheres screw heads will show signs of age. From what I see, that driver looks pretty good for 20+ years.:bouncy:

[edgewound]

I'll stick my neck out and confirm that is JBL D16R2445 diaphragm. Looks to be missing a 6-32 mounting screw just above the positive (non-red marked) terminal. The red signifies 16 ohm...a green mark would signify 8 ohms. Corrosion on screw heads is not unusual.

[scott fitlin]

Looks OK, all metals show some discoloration over time, but i dont see any rust or corrosion!

Looks like an authentic JBL Ti phragm to me, too!

[John W]

What does the writing in felt tip marker signify inside of these drivers? All of the ones I have seen have some sort of numbers or markings inside. I this quality control?

[edgewound]

What does the writing in felt tip marker signify inside of these drivers? All of the ones I have seen have some sort of numbers or markings inside. I this quality control?

Yes...I believe it has to with the tolerance of the top plate/gap alignment.

[scott fitlin]

What does the writing in felt tip marker signify inside of these drivers? All of the ones I have seen have some sort of numbers or markings inside. I this quality control?Could also be the driver was sent back to JBL to be recharged! I have 2441,s that I have since we bought em new, and the top plates are clean, no markings!

1 year, about 3 years ago, I sent two back to JBL to be remagged, and they came back with magic marker on the top plate, on one it says +2.

Its identifying something that was done!

[frank23]

Hi, I have just bought these drivers for 225 euro. A good price I think. I will pick them up in the next few days.

Maybe the numbers mean the "out of centerness" of the magenetic gap in tenths or hundreds of millimeters?

frank

[Steve Schell]

Hi Frank, guys,

The titanium diaphragm looks identical to the ones in my 2445Js, so I believe it is a JBL replacement unit.

The top plate is highly oxidized; it was shiny bright when new. Considering this and the rust on the diaphragm mounting screws, it appears that this driver may have seen severe duty in an outdoor installation. It may function perfectly fine despite this, but it would be worth your trouble to remove the diaphragm and clean the gap. Drivers like these often have dirty gaps.

The markings on the top plate indicate relative height spacing of the top plate and phasing plug relative to JBL's spec, to the best of my knowledge. This was measured in four positions when the driver was first assembled, to ensure that diaphragm to phasing plug spacing is within tolerance. The crude El Marko graffitti seems out of place on a precision product, but they all seem to have it.