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Dr Zeus 2nd February 2011 04:52 AM

Rockford T5002 Outputs sub
Ive got this amp here with one of two channels blown. I clipped all FETs which all shorted i nthe bad channel, and the amp powered up and plays out of the good channel.

The output transistors are FQA36P15 and FQA46N15. I tried a few places and it looks like theres a few mis-matched parts available from different resellers. Arrow has the Fairchild FQA46N15 which is fine (and good price). They are out of stock on the FQA36P15 and no place seems to be selling the FQA36P15. Digikey comes close with an IXYS brand, IXTQ36P15P but they are pretty expensive and IXYS does not seem to have their branded counter-part.

Is there some other, better fet or retailer I can get replacement or substitute fets for this and other style, newer RF amps?

Perry Babin 2nd February 2011 04:59 AM

FAIRCHILD FQA36P15 is in stock|BuyFQA36P15|FQA36P15|

mikealanlee 2nd February 2011 05:00 AM

Newark looks like they have "FQA36P15" in stock. 49 pieces. They are a good distributor, I've used them lots. Avnet express has the "FQA46N15", also good distributor.

Also check out "". It's a great resource for finding parts.

Dr Zeus 2nd February 2011 05:06 AM

There you go! Thanks!

Dr Zeus 10th February 2011 07:04 PM

I got the right outputs and installed, "FQA36P15" and "FQA46N15" into Q1024, Q1025, Q1026, and Q1027. now when the amp powers up, it draws my power supply down to protection and the cycles power about every 2 seconds. Previously, I had clipped 3 out of these 4 outputs, and the one which survived was playing 1/2 the waveform on the scope.

Perry Babin 10th February 2011 07:05 PM


Gate resistors?

Dr Zeus 10th February 2011 07:53 PM

OK I did find R1065 which is a 0.10 ohm resistor totally open. I replaced all four in the amp but it still experiences the problem.

I turned the bias pot fully counter clockwise and the problem still happens. While the amp is power cycling, the voltage accross the source resistors is ~0.040 in the bad channel. Too high. 0.001 in the good channel.

Perry Babin 10th February 2011 08:19 PM

Is the voltage across each of the source resistors virtually the same or do you have 1 or more that have significantly higher or lower voltage across them?

Are the 3 legged jumpers properly soldered to the MEHSA insulator?

Is the bias transistor intact/in place?

Dr Zeus 10th February 2011 09:22 PM


Are the 3 legged jumpers properly soldered to the MEHSA insulator?
I think between the open source resistor and the 3 legged jumper, I think that was it.

Testing amp thouroughly now.

mschmitz 9th July 2015 05:47 AM

Rockford 500.2 Amp with same problem
I just replaced the MOSFET for the bad channel and the amp gets hot on that channel fast and draws significant current, but the potentiometer does not change anything. Fosgate is very secretive and will not help with schematic or advise. They only refer to 2 repair guys in hte US and will not even sell parts. How did you solve the problem with the T5002? Mine has the same voltage difference: Good channel 2+ Volt G-S, bad channel 4+ Volt G-S

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