# Phoenix Gold XS4600 one channel popping



## computerjlt (Nov 29, 2010)

Alright guys I'm a little out of my league here. I've used this site to troubleshoot some amps and mobile audio stuff and have to say this site is awsome. But I have a problem I need help on!

I have a phoenix gold XS4600 4ch amp that 3 of the four channels work perfectly. On the right rear channel randomly it stops playing music and starts popping loudly like its sending DC/Rail voltage to the speaker. There isn't much pattern to the issue and i've done some poking with my DMM but I don't know what else to check. 

I'm powering the amp off of a 5amp bench power supply so as not to overload anything to the point of smokey failure but I did note that with a speaker hooked up amperage draw jumps significantly when it's "popping" I unhook the speaker and popping stops obviously and amp draw stabilizes. While its popping the other channels keep on playing. This amp does seem to have excessive idle amperage draw; about 2.5A compared to about .5-1A for the memphis and power acoustik amps i have with me to referance (though some of that I attribute to the PG amp being older and better built)

One thing to note this amp used the little DIP IC resistor network to control crossover points and the one for the rear has 2 messed up pins. The only way that amp will play out of the right rear is if they "crossover defeat" button was pressed; and pressing that button while the amp is powered will reward you with a very powerful THUD out of the right rear channel. I dont mind the bulit in crossover not working as I will be using an outboard one but I plan on fixing that issue if i get the right rear channel to work.

Also that channel has an excessive amount of 60HZ hum compared to the other channels (RCA's and speakers swapped around and moved around physically to rule out 120v ac cord interferance or a bad speaker). I dont know if thats relevant but I thought i'd mention it.

My guess is repeated pressings of that button or that IC not being right caused something in the right rear channel to overload partially fry'ing a FET or something. 

I don't have a scope unfortunately but have a few DMM's and good soldering equipment. 

Anyway any input on what I should check or replace? I'm thinking about just ordering some fets and replacing them one by one until it works but thats not the most cost effective means lol


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## computerjlt (Nov 29, 2010)

no one? are there any other forums you guys would know about to ask these sorts of things?


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## lust4sound (Apr 9, 2008)

computerjlt said:


> Alright guys I'm a little out of my league here. I've used this site to troubleshoot some amps and mobile audio stuff and have to say this site is awsome. But I have a problem I need help on!
> 
> I have a phoenix gold XS4600 4ch amp that 3 of the four channels work perfectly. On the right rear channel randomly it stops playing music and starts popping loudly like its sending DC/Rail voltage to the speaker. There isn't much pattern to the issue and i've done some poking with my DMM but I don't know what else to check.
> 
> ...


They will ignore you because you do not have a scope..


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## computerjlt (Nov 29, 2010)

Well i just picked up a 2ch beckman industrial 40mhz scope sunday. Ive been poking around and found the right rear - terminal will go to +30v when the amp starts cracking out (+ term is fine).
Also the same signal ( random +30v) comes in and out of one of the big fets so im guessing its a smaller tra.sistor that triggers the bigger fets thats dying? Or due to the patern thats repeating maybe a cap?

I took the main board out of the amp to get to the bottom of the pcb but now my porob is i cant repeat the issue cus the fets that are now floating w/o a heatsync get too hot too fast b4 the amp glitches


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## bfowler (Nov 25, 2009)

might try asking the phoenixphorum. i know at least 2 ex-pg techs post there


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## jacampb2 (Dec 3, 2010)

computerjlt, it looks like your post you made over at the phoenix phorum got lost when they upgraded the BB software tonight. Might want to repost again for the day crowd tomorrow!

Good Luck,
Jason


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## computerjlt (Nov 29, 2010)

dang lol; reposting now


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