Reading

[rloggie]

I saw a pr. of 375 drivers that looked nice but when I measured them one was 6.7 and the other read 92.7! Would someone tell me what this likely indicates?
Thanks!

[rloggie]

BTW this driver still has the wax seals.

[johnaec]

Bad internal connection, adding resistance?

John

[rloggie]

The seller said they "sound great". Do you think it would hurt them to try to run them? They were just shipped to my home, maybe that's the conection issue.

Another question, the "good one" has the wax missing and I'd like to open the back and see if its the original diaphram. Will opening it cause any problem?

[edgewound]

The good one missing the wax seals probably has a more recent replacement diaphragm. The one with 92+ ohm dc res probably has corrosion somewhere inside or a fatigued solder joint, etc. It wont hurt to take the back off the good one and have a peek, just be careful to keep your screwdriver away from the diapragm/phase plug lest it succumb to the magnetic pull and damage the dome....ouch....and BTW, the one with the wax seals in place and 92+ ohms dc is basically useless as a transducer....needs to be fixed if you're gonna use it.

[Zilch]

Before opening the sealed one, try cleaning the external binding post contacts. Make sure you have a good connection and test again....

[LE15-Thumper]

Bad internal connection, adding resistance?

John

I found loose screws on the diaphrams where the wire hooks up from the back cover of the driver. I had to crack the wax seals on both my LE85's as well as my LE175's. They kept cutting out on certain bass notes.

[rloggie]

Here's a shot of the diaphram on the "opened" 375. Looks like it's the original wouldn't you say?

[edgewound]

Robin,

That diaphragm looks good, and looks to be genuine JBL...but it could very well be the correct replacement diaphragm installed. No guarantee that it's the original installed on the assembly line. I'd really be more concerned with the one that's not working properly. It's been discussed before here that 40 year old diaphragms can lose sound quality from fatigue. Nice pieces, though.