Crown XLS402 amp problems

BrianQ823 · 02:43 AM

Hi all.....I have this amp and it is used for our monitors. It has all the sudden started to act up. When turned on it will come on for about 2 seconds and then turn back off. It cannot be turned back on for around 5 minutes....kinda like there is some sort of circuit breaker that resets in that amount of time. I have disconnected the output connectors from the pcb and the problem persists. Any help is greatly appreciated. BTW...I don't have to push the reset button because it is never tripped.

Zero Cool · 25th June 2010, 03:56 AM

I have repaired several of these amps and they seem to blow easy. Crown buys these from C-Audio.

There is a soft start circuit that will prevent these from turning on if there is a problem. there should be a large white resistor. i bet it gets real hot real fast!

Do you have any DC one the output of the main board to the Relay board? if so you have a blown channel and it takes out all the output devices and most of the small TO-92 devices and then some. I have also seen these melt the speaker relays closed and to ground. so your in for quite a repair. chunk it and spend the money you would have spent fixing it on a QSC with 6 year warranty...

BrianQ823 · 26th June 2010, 05:04 AM

The only component that gets hot....and fast.....is the blue colored component in the PTC1 position. There is nothing in the PTC2 position. I can't seem to find R22. I can plainly see R21 and R23 thought (big resistors). Neither of those are hot either. It seems like Relay1 never closes or engages. The Crown "checkout" manual states this:
"The soft-start components include R22, PTC1, PTC2 and the contacts of RLY1. At switch-on, R22 limits surge current and PTC1, PTC2 protect R22 from overheating. After a few seconds, the protection circuit energizes RLY1 coil, closing RLY1 contacts which short out R22, PTC1, PTC2, allowing full power operation."
Could Relay1 not be working and cause this symptom....and where is that R22 located? Could the protection circuit be bad and how would you check that? I wish I could buy another amp, but, at this point in time...my best and only option is to fix this one. The economy and all.........

25th June 2010, 02:34 AM	#1
BrianQ823 diyAudio Member Join Date: May 2010	Crown XLS402 amp problems Hi all.....I have this amp and it is used for our monitors. It has all the sudden started to act up. When turned on it will come on for about 2 seconds and then turn back off. It cannot be turned back on for around 5 minutes....kinda like there is some sort of circuit breaker that resets in that amount of time. I have disconnected the output connectors from the pcb and the problem persists. Any help is greatly appreciated. BTW...I don't have to push the reset button because it is never tripped. Last edited by BrianQ823; 25th June 2010 at 02:43 AM.

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25th June 2010, 03:56 AM	#2
Zero Cool Audio Junkie diyAudio Member Join Date: Sep 2004 Location: MN	I have repaired several of these amps and they seem to blow easy. Crown buys these from C-Audio. There is a soft start circuit that will prevent these from turning on if there is a problem. there should be a large white resistor. i bet it gets real hot real fast! Do you have any DC one the output of the main board to the Relay board? if so you have a blown channel and it takes out all the output devices and most of the small TO-92 devices and then some. I have also seen these melt the speaker relays closed and to ground. so your in for quite a repair. chunk it and spend the money you would have spent fixing it on a QSC with 6 year warranty...

26th June 2010, 05:04 AM	#3
BrianQ823 diyAudio Member Join Date: May 2010	The only component that gets hot....and fast.....is the blue colored component in the PTC1 position. There is nothing in the PTC2 position. I can't seem to find R22. I can plainly see R21 and R23 thought (big resistors). Neither of those are hot either. It seems like Relay1 never closes or engages. The Crown "checkout" manual states this: "The soft-start components include R22, PTC1, PTC2 and the contacts of RLY1. At switch-on, R22 limits surge current and PTC1, PTC2 protect R22 from overheating. After a few seconds, the protection circuit energizes RLY1 coil, closing RLY1 contacts which short out R22, PTC1, PTC2, allowing full power operation." Could Relay1 not be working and cause this symptom....and where is that R22 located? Could the protection circuit be bad and how would you check that? I wish I could buy another amp, but, at this point in time...my best and only option is to fix this one. The economy and all.........

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