JBL PRX 625 fuse issue

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   Setup is Pair of JBL 618 XLF together with Pair of PRX 625. Last night rented out this speakers to a party. Customer describes the scenario like this:
Playing music middle volume (room is small). I have lower quality mic with a switch on. Mic was used throughout the evening now and then. Later on the night when switch mic on the speakers bumps up and dies.
Today I see that the external fuse on back of the speakers are ok but when opened I can see the internal fuse is blown in both PRX 625 speakers. (618 XLF seems all fine)

I see online this speakers had some overheating issues.

When look at the amp module in 625:s one component seems to be running hot see pic (glue is brown and smells little burnt). But when I replace the fuse everything is working fine again.

What do you guys say can it be safe to use even if the component looks burned?

Would it be wise to get rid of those JBL:s and getting some RCF:s or equvalents?

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serioussound Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 01 December 2013 Status: Offline Points: 443	Post Options Post Reply Quote serioussound Report Post Thanks(0) Quote Reply Topic: JBL PRX 625 fuse issue Posted: 26 January 2020 at 6:53pm
	Setup is Pair of JBL 618 XLF together with Pair of PRX 625. Last night rented out this speakers to a party. Customer describes the scenario like this: Playing music middle volume (room is small). I have lower quality mic with a switch on. Mic was used throughout the evening now and then. Later on the night when switch mic on the speakers bumps up and dies. Today I see that the external fuse on back of the speakers are ok but when opened I can see the internal fuse is blown in both PRX 625 speakers. (618 XLF seems all fine) I see online this speakers had some overheating issues. When look at the amp module in 625:s one component seems to be running hot see pic (glue is brown and smells little burnt). But when I replace the fuse everything is working fine again. What do you guys say can it be safe to use even if the component looks burned? Would it be wise to get rid of those JBL:s and getting some RCF:s or equvalents?

Conanski Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 26 January 2006 Location: Ottawa, Canada Status: Offline Points: 2537	Post Options Post Reply Quote Conanski Report Post Thanks(0) Quote Reply Posted: 26 January 2020 at 10:16pm
	The first thing you got to know is that any story a renter cooks up is total 100% BS. They flogged that gear mercilessly! Class D amps do generate heat though, some components get quite hot but if a bit of glue is all that was "damaged".. the speakers still work even cranked up? Then all is good. It's hard to know what that fuse does without a schematic, blown fuses in the power supply generally means something died and you would know because the speaker would not work anymore, but it could be a driver protection fuse too which did it's job if that is the case.

mk2_ginger_biscuit69 Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 03 November 2008 Location: Brighton Status: Offline Points: 7801	Post Options Post Reply Quote mk2_ginger_biscuit69 Report Post Thanks(0) Quote Reply Posted: 26 January 2020 at 10:56pm
	indeed, JBL like to fuse their drivers to protect them, could have just been super lucky!
	''Remember that the object of a subwoofer is to enhance the output of your main speakers, not overpower it'' ''Dubstep - an elongated electronic fart''

kedwardsleisure Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 4947	Post Options Post Reply Quote kedwardsleisure Report Post Thanks(0) Quote Reply Posted: 26 January 2020 at 11:55pm
	If that's R610 you've circled, they get a bit hot anyway, probably just a red herring. It wouldn't hurt to replace the burned glue as it may turn conductive in the future, if that wasn't what blew the fuses in the first place. I suspect the speakers were subject to a simultaneous transient overload, either mic feedback that made them screech or possibly a power spike (were they on a generator?).
	Kevin North Staffordshire