[robmangler]

one of my speakers started cutting out at any volume and seemingly randomly. I discovered that by tapping the woofer cone it would come back on and work perfectly until it didn’t. I was told that one of the leads to voice coil was detached. I thought I could fix it.

I cut the dust cap off (carefully) and found that, of course I couldn’t even find the wires so I decided to get replacement drivers. Confident I was on the right track.

I replaced the drive and surprise! – same problem.

Can anyone tell me what the heck is going on and how can I fix it?

[Dillen]

If the whole speaker goes silent, failing contact in the safety (thermo-) relay.
Give it a blast of contact cleaner and excersize it a couple dozen times.

Martin

[chartz]

What Martin says 👍🏻

[robmangler]

Do you mean the built-in protection circuit cut off switch on the front of the speaker?  (I was wondering about that…)

Thanks,

Rob

[robmangler]

And yes the whole speaker goes silent.

Thanks,

Rob

[Dillen]

No.
The small thermo relay has a yellow reset button sticking out the front near the “Overload” printing.

Martin

[robmangler]

Sorry for all the questions—-  OK I’ll give it a try. Do you think I need to open the speaker and take the reset button out to work on it or can I just spray into the reset button from the front? Sparingly of course…

Thank you sir!

Rob

[robmangler]

Thanks for the help Martin. I should have jumped on here some time ago. That did the trick! what a relief!

[robmangler]

Well, I did what Martin suggested and it work beautifully. For several days. Now same old problem.

Can I just bypass that?  My days of cranking it up that high are long gone.

[robmangler]

Or perhaps I can find a replacement?

[AdamS]

If the relay is the same as that used in the MS150.2 loudspeakers that I own, then I believe it is no longer available.

However it”s not difficult to pop the case off the relay and clean its contacts with some fine emery paper, which should do the trick.

It would also be worth replacing any electrolytic capacitors in the protection circuit – if they have aged and dried out then they can cause problems with the circuit’s operation.

[robmangler]

Thanks for the feedback. the speaker is now working again – maybe the di-oxit has found its way in. been listening for several days now and still works like a charm. I will attempt the fix you mentioned if problems flair up again. Thanks!

[Author]

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