JBL Pro 2120 speaker dilemma

[songseeds]

Hi all,

I'm the original owner of 4-10" JBL Pro speakers, Model 2120. They were purchased around 1971 by our rock band and used as floor monitors for about a year. Since then they have not been used. I've moved them from one storage location to another and I've now decided to look into selling them.

I've checked them out and while 2 of them seem to be working fine, the other 2 have some sort of intermittent problem. I've searched the forums and seen advice about twiddling with the leads to see if you can make them cut in and out at will, but this has not worked on either.

I've also seen that repair kits for this model are no longer available.

I'd be thankful for any advice those of you in the know might be able to help me with.

Specifically:
1) any further troubleshooting I might try,
2) any speculation as to why they cut in and out, and
3) any advice on how I might get them repaired.

Thanks,

Rick Clingman

[speakerdave]

Possibly the input clips are loose or shorting. Try attaching alligator clips to the leads inside the frame. Also, the voice coils might be partially shorted. Are you sure your test amp (solid state?) is not cutting out due to low load impedance in the voice coil?

Unless fiddling or input repair fixes them, I would sell the questionable ones as cores. There may be buyers interested in those Alnico cores because as musical instrument drivers aftermarket recones will meet the requirements of some, but I do not think it would pay to have them put in yourself.

Hi all,

I'm the original owner of 4-10" JBL Pro speakers, Model 2120. They were purchased around 1971 by our rock band and used as floor monitors for about a year. Since then they have not been used. I've moved them from one storage location to another and I've now decided to look into selling them.

I've checked them out and while 2 of them seem to be working fine, the other 2 have some sort of intermittent problem. I've searched the forums and seen advice about twiddling with the leads to see if you can make them cut in and out at will, but this has not worked on either.

I've also seen that repair kits for this model are no longer available.

I'd be thankful for any advice those of you in the know might be able to help me with.

Specifically:
1) any further troubleshooting I might try,
2) any speculation as to why they cut in and out, and
3) any advice on how I might get them repaired.

Thanks,

Rick Clingman

[songseeds]

Hi speakerdave,

RE: the input clips: I did try tweaking them but they seem to be very stable. On the 2120, the lead connectors are mounted on the housing and the input clips are then inside the housing. It all feels very solid. Haven't tried alligator clips to bypass it just in case the problem is not palpable but I'll do that soon. Nonetheless, major manipulation of the whole input hardware stage has not resulted in my ability to make them cut in or out.

RE: my test amp: My test amp is just a solid state Teac receiver (which I used just because it was the easiest thing I have to connect bare speaker wire) and I'm not sure how I'd troubleshoot such a thing. Could you elaborate?

RE: repair: Do you know whether these can be re-coned as K110s? I suppose they'd be useful for guitarists at that point, eh? Don't know how that compares with what I could sell them for as cores. Any idea?

thanks,

rick

Possibly the input clips are loose or shorting. Try attaching alligator clips to the leads inside the frame. Also, the voice coils might be partially shorted. Are you sure your test amp (solid state?) is not cutting out due to low load impedance in the voice coil?

Unless fiddling or input repair fixes them, I would sell the questionable ones as cores. There may be buyers interested in those Alnico cores because as musical instrument drivers aftermarket recones will meet the requirements of some, but I do not think it would pay to have them put in yourself.

[subwoof]

just why does everyone think that intermittent operation ( or none ) is a short???

current flows in a loop and if there is no action, the loop is OPEN...jeez...

anyways the 2120 is a K120 with the pro frame - and the kit is now NLA.

And unfortunately any kit that would make that a functional speaker ( 2202, 2203, 2204, et all ) with the correct gap is also NLA..

feel means nothing. use the clips as mentioned - also connect the receiver and wiggle leads while running to see...corrosion in *forty years* just might have made an issue..

have a competent speaker repair company replace the tinsel wires before making any decision on scrapping / selling as cores. if it moves, it breaks...

sub

[ivica]

j................
anyways the 2120 is a K120 with the pro frame - and the kit is now NLA.

And unfortunately any kit that would make that a functional speaker ( 2202, 2203, 2204, et all ) with the correct gap is also NLA..

................
sub

Hi subwoof,

May be I am wrong, but 2120 is 10-inch speaker (say almost as K110....etc), but mentioned 2202.....are 12-inch.....

Regards
Ivica

[subwoof]

oops....I was thinking of the 2130... when I worked for a JBL dealer in the late 70's we got the model numbers all mixed up sometimes....

the 2120 is a D110 with a pro magnet..it was popular in some OEM church organs and PA's.

[speakerdave]

. . . just why does everyone think that intermittent operation ( or none ) is a short???

current flows in a loop and if there is no action, the loop is OPEN...jeez...

Well, OK--fair enough. I guess in the upstate New York diary farm dialect I learned following my father around in the mud "short" meant 'something wrong' electrically.

. . . have a competent speaker repair company replace the tinsel wires before making any decision on scrapping / selling as cores. if it moves, it breaks...

Of course.

[speakerdave]

. . . Do you know whether these can be re-coned as K110s? I suppose they'd be useful for guitarists at that point, eh? Don't know how that compares with what I could sell them for as cores. Any idea? . . .

I think the motor and frame for the 2120 and the K110 are the same, but again, there are no more factory kits.

[ivica]

Hi speakerdave,

RE: the input clips: I did try tweaking them but they seem to be very stable. On the 2120, the lead connectors are mounted on the housing and the input clips are then inside the housing. It all feels very solid. Haven't tried alligator clips to bypass it just in case the problem is not palpable but I'll do that soon. Nonetheless, major manipulation of the whole input hardware stage has not resulted in my ability to make them cut in or out.

RE: my test amp: My test amp is just a solid state Teac receiver (which I used just because it was the easiest thing I have to connect bare speaker wire) and I'm not sure how I'd troubleshoot such a thing. Could you elaborate?

RE: repair: Do you know whether these can be re-coned as K110s? I suppose they'd be useful for guitarists at that point, eh? Don't know how that compares with what I could sell them for as cores. Any idea?

thanks,

rick

May from the:

https://taweber.powweb.com/weber/neo10.htm

some help can be get.

Regards
Ivica