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Hello all. I am new to the forum, and am seeking advice on how to refurbish my '79-era Altec Lansing Model 19s, one of which is apparently completely dead and the other of which only the woofer is in operation (sounds good).
From what I gather, since the woofer(s?) seem to be okay, it may be that the crossovers are at fault in both cases.
Where do I go from here?
Thank you.
Jack Black
More information would be helpful. Are these speakers new to you? If so, do they look like they've had a hard life? If they've been yours, what is the history of the failures?
Your completely dead cabinet may be the result of a disconnect inside. It's unlikely the crossover is fried. If the woofer and driver are fried it would be a result of abuse, as well as the driver in the other enclosure. I recommend that you pull all of the components and put a VOM on them to check if the voice coils are open.Quote:
Originally Posted by Jack Black
The driver diaphragms can be purchased from Great Plains Audio, as well as having the 416 re-coned if necessary. Do not buy after market diaphragms. I have found that one of the mounting screw holes in the ring on one I replaced recently on a friends system does not line up properly. Plus, they will most likely be made of titanium. Blech!
If one of the crossovers is damaged, you're better off finding a replacement on Ebay and be done with it, unless you're adept at making electronic repairs on your own.
H.F.
Thank you for the replies.
I bought them new in ’79, and used them for many years. Once of my A/V setups had another pair of speakers (center channel) between, so I didn’t notice exactly when the 19s went out, sometime after ’91.
The last time I really heard both speakers, they were performing like new.
They were shipped locally about five years ago, and have been shipped cross-country recently, so were subject to some jostling.
The woofer cones and surrounds look good; they haven’t deteriorated noticeably as I have seen on some other speakers.
I guess it makes sense that the mid- and high- frequency controls are inoperable.
I noticed a post on one of your threads saying that a radio-station tech was able to repair his crossovers.
Question: will measuring the impedance (resistance) across the terminals tell me anything? What should it read?
Question: is there anything I should know about pulling the components; the drivers come out first from the front panel, right? Is there enough slack in the wiring so as not to make things too difficult? Are the connections soldered, screwed, what?
Question: the foam around the horns is crumbling. Any suggestions what to replace it with?
Again, thanks.
Jack
Better to take resistance measurements at the terminals of each driver, with them disconnected
from the crossover. Very roughly, something over 4 ohms and less than 10 ohms would be a normal
range for these drivers... much more (say 20+, or if it is not stable) and there may be problems...
much less, and there could also be problems.
If you take the woofer from the front, the black/red terminals are where the leads from the
crossover go. They are push-to-release type terminals. You should be able to take the woofer
out carefully/partially and then release the wires... but check the slack as the woofer is coming out.
You can hook the woofers up directly to a receiver or amp to test for audio... just don't play them stupid loud.
You can also hook up the compression driver this way, but you'd want to keep the level way down (and
turn the bass down if possible), as they won't take much bass signal before blowing up. Even if it works
it will likely sound like tinny crap without the woofer or horn loading. Just getting audio reproduced
at all is a good start.
If one crossover works, then you might try the compression driver using that crossover before
calling it a blown diaphragm.
The best course of action might be to take the drivers out and have a shop that repairs loudspeakers
give them a quick look-over. Same with the crossover if loose wires or terminals isn't the issue.
It's not super complicated, but it is a somewhat specialized field in that some experience/training
is very helpful.
I believe there are aftermarket sources for the foam around the horn.
http://www.audioheritage.org/photopo...eteens_004.jpg