# memphis st 3004



## lwrd93 (Apr 6, 2009)

i had this hooked to my front speakers and hooked a set of off brands up to the same ch, drove around to test them and when i was pulling back in the sound went off. checked the amp and it was going from power to protect and kept doing it. unhooked all speakers and still does it, im guessing i ran the ohm load wrong? what would this have messed up? took apart and nothing looks blown or visible...


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## timwebb (Oct 25, 2011)

shorted power supply.


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## lwrd93 (Apr 6, 2009)

is there away to get a replacement?


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## timwebb (Oct 25, 2011)

u got a pic of it?


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## lwrd93 (Apr 6, 2009)

i can get one.. what you wana see?


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## lwrd93 (Apr 6, 2009)




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## xMplar (Feb 18, 2009)

did you check the fuses inside it i havent even heard of this model so im not sure but it could be a faulty output stage or even power supply or straight up fuse if this is the pic of the amp and you bought it neww however then there goes your warrenty

quickest way to loose warrenty on an amp take the back off it

Ren
xMplar


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## lwrd93 (Apr 6, 2009)

yes both fuses are good... it didnt have a warranty so why not open it??


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## timwebb (Oct 25, 2011)

take a look around the transformer for any damage.


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## lwrd93 (Apr 6, 2009)

they all look good..


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## timwebb (Oct 25, 2011)

its a short on one of them.


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## lwrd93 (Apr 6, 2009)

but which?? got a pic of what im sopose to look for?


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## timwebb (Oct 25, 2011)

the ones next to the power supply on the sides.


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## timwebb (Oct 25, 2011)

this are the most common area i seen go out these memphis amps.


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## lwrd93 (Apr 6, 2009)

by looking at them can you tell? or can you use a ohm meter?


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## timwebb (Oct 25, 2011)

u need a ohm meter or dmm. if u read 0 between two legs of any transistor its bad.


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## brunofxsoft (Mar 9, 2011)

Nice amp.


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## lwrd93 (Apr 6, 2009)

Ya if I can fix it ...


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## timwebb (Oct 25, 2011)

u fixed it?


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## lwrd93 (Apr 6, 2009)

I wish..


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## chithead (Mar 19, 2008)

Any luck?


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## lwrd93 (Apr 6, 2009)

no, still trying to figure out where to test on it and what.


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## ATOMICTECH62 (Jan 24, 2009)

Send it to me and I will send it back working.For a fee of course.


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## lwrd93 (Apr 6, 2009)

my friend in the army is coming home for xmas.. and this is pretty much what he does, so maybe i will get lucky and he will know what part is bad and can replace it for me.. where do you order your parts from??


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## ATOMICTECH62 (Jan 24, 2009)

MCM,Mouser,Digikey,Farnell and sometimes Ebay.


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## chithead (Mar 19, 2008)

I'd like to figure out what the part number is for the gain control, and for the RCA inputs. Might just go ahead and replace both gain controls and the crossovers while I'm at it.


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## ATOMICTECH62 (Jan 24, 2009)

That amp needs the whole power supply rebuilt.First thing is you will never be able to get those mosfets off of that strip there soldered to.the chip resistors need replaced and so will the 4 little transistors that drive them.There next to the black 16 pin chip that has tl494 on it.and the 494 chip will need replaced.the mosfet that is burned is most likely an IRF3205 and they all need replaced.


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## lwrd93 (Apr 6, 2009)

How much am I looking at in parts?


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## ATOMICTECH62 (Jan 24, 2009)

The parts arent that much,its the labor thats the problem.the strips those mosfets are soldered to are not available.They have to be reworked and it takes experience.


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## ATOMICTECH62 (Jan 24, 2009)

They have MEHSA written on them


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## lwrd93 (Apr 6, 2009)

that wasnt the memphis amp i sent you pics of just so you know.. im not sure whats wrong with this memphis amp.


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## ATOMICTECH62 (Jan 24, 2009)

Yeah.It was a rockford.


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## lwrd93 (Apr 6, 2009)

what about this memphis?


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## ATOMICTECH62 (Jan 24, 2009)

Hard to say without trouble shooting it but its most likely irf540's and irf9540's in the output section of a channel.


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## lwrd93 (Apr 6, 2009)

how do you test those?


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## Robert_J (Nov 9, 2006)

I don't like thread hijackers but I think I'm in the same boat as the OP except with a mono Memphis amp from the same line.

I watched the 9 part You Tube series on car amp repair. I went over this amp with a bright LED flashlight and saw no issues on the caps, board or transformer. When I started checking the FETs, I noticed the tops of 2 by the big transformer were cracked. Based on Tim's comment below, I seem to have a common problem.



timwebb said:


> this are the most common area i seen go out these memphis amps.


I removed the 3 screws on the side and the holder inside came loose. All of the transistors were blown. They even had burnt markings on that holder. Based on that, I'm going to try my hand at amp repair for the first time. The existing FETs had 3 markings:
FW0132
FQP
50N06

I looked up all 3 on Digi-key but only got hits on the 50N06. I have 37 options to choose from. I eliminated the ones that didn't look like the originals but other than that, what do I need to look for? Digi-Key - FQP50N06L-ND (Manufacturer - FQP50N06L) Does that look like a good replacement? I know to make sure they come from the same lot. 6 replacement parts for $9 plus shipping seems like a great deal. I'm willing to get more expensive parts if that's what I need.

Tim,
We may have a mutual friend in common. Spencer has mentioned an amp repair guy in Memphis and I assume that might be you.


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## timwebb (Oct 25, 2011)

oh yea.thats me... that transistors isnt the stock part for the amp. irf3205 are best. and irfz44 are good to. ive rebuild around 30 of these amps.and those the two fets i always use.


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## chithead (Mar 19, 2008)

Well what pot do they use for the gain control? I am having a heck of a time locating those and the RCA inputs.


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## timwebb (Oct 25, 2011)

might be 20k.


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## Robert_J (Nov 9, 2006)

timwebb said:


> oh yea.thats me... that transistors isnt the stock part for the amp. irf3205 are best. and irfz44 are good to. ive rebuild around 30 of these amps.and those the two fets i always use.


I searched on irf3205 and got 27 hits at Digikey. I sorted to see all of the "through hole" models and that narrows it down to 5 options. What is next? Continuous current or max power?

Did Spencer buy a ST-1000D with missing end-plates from you?


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## timwebb (Oct 25, 2011)

im waiting to get that back lol i wasnt done with it. i let him see two of those amps.

IRF3205PBF for International Rectifier | Arrow Electronics Components


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## Robert_J (Nov 9, 2006)

Thank you so much. That's even a better price than I expected.

Taking the other discussion private.


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