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Electronics => Repair => Topic started by: Perrin21 on March 09, 2020, 01:29:56 am

Title: Myryad MA240 power amp pops when shutting down.
Post by: Perrin21 on March 09, 2020, 01:29:56 am
hi, I have 4x myryad MA240 Amplifiers (running bridged as monoblocs) and one has started to pop when the relay shuts off as its powered down. the other 3 amps don't and this is a new issue for the one that does. Any ideas what is causing it? could it be the relay is worn and needs replacing? or could it be something else? otherwise it works fine.  I've checked for DC on the terminals and there's nothing.
Title: Re: Myryad MA240 power amp pops when shutting down.
Post by: David Hess on March 09, 2020, 02:15:15 am
If it has a relay in series with the output, then that could mean that a DC offset has developed for whatever reason.
Title: Re: Myryad MA240 power amp pops when shutting down.
Post by: Renate on March 12, 2020, 03:40:31 pm
I would suspect that the DC is crashing too quickly for the protect circuit to kick in.
Since you have a bunch of these things, it should be easy to compare.
Put your scope on single sweep and watch the collapse of the DC power supplies when you shut it off.
If the supplies are bipolar a big difference between plus and minus could certainly cause problems.
I would suspect that the electrolytics on the bad unit are low in value.