Diaphragm Replacement Instructions

[Russellc]

Hello

Could someone tell me or direct me to instructions for replacing/inspecting the diapram? The model in question is a 902 8b.

I assume there is more to it than just removing the three screws, it appears that the black rubber-looking cap must also be removed?

Thanks in advance,
Russellc

<font color="#FFFFFF" size="1">[ April 05, 2003 11:01 AM: Message edited by: Todd W. White ]</font>

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http://nleinternet.net/alteclansingu...909-8AData.pdf

[Todd W. White]

Hi Russell!

Coincidentally, I just finished a new instruction sheet on this very subject for Bill at Great Plains Audio. It is similar, but more informative than the old one that the pre-1998 Altec distributed, and includes instructions for the old 800-series drivers as well.

I will be putting it on Bill's website this weekend, but can e-mail it to you when I get to the office this afternoon.

E-mail me privately and I will send it to you.

[email protected]

[Russellc]

Thanks for the answers all. Wunhuanglo, thanks for the diagrams. They show the black rubber deal on when they are showing where the cover screws are, but appears to be gone in the illustration showing the exposed dome. I undid my three screws, but the cap was still stuck on. I didn't want to force it untill I had more info, but it appeared that the black rubber looking thing was on top of it, possibly requireing its removal? Or do I need to just gently apply a little more force? The file you provided sounds like the three screws come out and the cap is off?

Thanks for the help
Russellc

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DON"T HATE ME IF THIS GOES SOUR!!!

On my 808's there is a loading cap that appears to be identical to the ones shown in the data sheet in the link. In the 808's it's much more like bakelite than rubber. Once the three screws holding the loading cap are removed, the cap itself just lifts off. On my 808's it was a bit sticky (dirt, age, whatever) but it came off with a just bit of a tug. In my experience I've found that it takes a little gentle rocking/alternating stress to remove the diaphragms from their voice coil gaps. They never seem to lift right out, though maybe it's the bakelite support ring that's sticking to the body of the driver after being screwed down for years and not the voice coil itself that puts up the resistance to removal (seems more likely).

What bothered me, and why I put the disclaimer upfront, is that the shellac or whatever it is that they used to cover the diaphragm leads was stuck to the inside of the loading cap. The loading cap has a channel milled into it to clear the arching lead, but in my 808's it was contacting the cap. I know from sad personal experience that these leads have the tensile strength of, oh, say, overcooked ramen noodles. I was amazed that the bit of "sticking" of the diaphragm lead to the loading cap didn't pull the lead right off, but it didn't.

I'm not sure why you're disassembling the drivers. If it's to replace the diaphragm, then it's of no concern.

[Russellc]

Hello,
I recently obtained a set of 908-8b, which originally should have had a symbiotic diaphram.
I just wanted to have a look and see what is in there, as when I hooked them up to my A-7s, I hardly noticed little if any difference in sound. It was however, a short listen. It just got me wondering what type of dia. was in my various drivers, I really have no idea! I assume part number or structural appearance would reveal what was in there.

Regards,
Russellc