JL Audio 500/1 Rev. 10

[hifonics hugh]

Q600-Q607 were all burnt . R600-R607 were all within tolerance with the exception of 605 being burnt.

Q600-Q607 Are IRFZ44N's. Is there a suitable substitue? After I put new ones in what should be my next step; other that replacing R605?

 

[Perry Babin]

The originals work perfectly fine. I've used Z46s in a lot of them and those seem to work without problems.

You'll need to check the output transistors to see if they're shorted.

When you reinstall it, make sure that you use the proper fuse. JL Recommends a 50 amp.

 

[hifonics hugh]

Perry once I cut all the z44n's away I measured .69V across the middle legs so I think the transistors are fine. It wont hurt to replace them though. The surface mount resistors(r605) maily where can I get them?

Thanks
Hugh

 

[Perry Babin]

With the black probe on ground and the red probe on the gate legs of the FETs, do you read ~5v DC about 15 seconds after the amp is powered up?

 

[hifonics hugh]

yes all are approx 5 volts with the exception of q605 and im sure that coz there is no r 605 green led lights up too. Looks good so far.

 

[Perry Babin]

If it doesn't have any shorted output transistors, all you may need to do is replace the out of tolerance resistor and the power supply FETs.

 

[hifonics hugh]

Sorry its been awhile Perry. Let me ask who is a reputable source for the fet and resistors

Thanks
Hugh

 

[Perry Babin]

See post #2 of your orion 500.4 thread.

 

[hifonics hugh]

Perry what part number did you use to replace the sm resistors why type and tolerance?

Id like to put a bom together for all the parts I need for the several amps so I can pay shipping once.

 

[Perry Babin]

I don't know what distributor you're using so I cannot give a part number. The resistors are 1206 size. Thin and thick film are OK.

Also, I've been using the IRF3205s in these amps for about the last year.

 

[hifonics hugh]

I don't know what distributor you're using so I cannot give a part number. The resistors are 1206 size. Thin and thick film are OK.

Also, I've been using the IRF3205s in these amps for about the last year.

Thank you.

Have you found the 3205 to be better performers than the originals? If there is an opportunity to improve the performance why not.

 

[hifonics hugh]

You can see r605 in the second photo from the top, headed for the hills......

 

[hifonics hugh]

Perry I went back and measured across the resistors again and this is what I got. Used two different meters to make sure.

R600 1.2 mohms
R601 53.6 ohms
R602 1.50 mohms
R603 54.8 ohms
R604 50 ohms
R605 on vacation
R606 55.3 ohms
R607 .525 mohms

 

[Perry Babin]

The 3205s won't make the amp any more powerful but they can withstand more stress. This gives the protection circuit a better chance of shutting the amp down before the power supply fails. A 40-50 amp fuse in the B+ line (after the amp has been tested and reinstalled in the vehicle) will provide further protection.

You need to look at the markings and determine if they're with tolerance.

 

[hifonics hugh]

Thanks

I think their all supposed to be 47 ohms if I'm not mistaken. Looks like a safe bet is to replace them all. Just wondering what I was thinking when I measured initially or why the measured values changed after sitting on the shelf for a few a good while.Go figure....

 

[hifonics hugh]

Can any one else confirm what they should be because I cannot read them. Mine must be charred badly because even after cleaning i cannot read any numbers even under a magnifying glass. There should be a number written on top??? 47R or something similar is what I expected to be able to read but no luck.

 

[hifonics hugh]

http://www.diyaudio.com/forums/car-audio/277002-jl-500-1-repair-2.html#post4387977

Perry I checked back to another thread so they are 47ohm. So only one of them would be within a 5% tolerance R604.

 

[Perry Babin]

Generally, when the PS FETs fail in these amps, it destroys all of the gate resistors so all have to be replaced.

 

[hifonics hugh]

Checked through my supplies and I actually had the 8 z44n's so I wait for the 1206 47 ohm resistors. I need to check Q608,Q609,Q610,Q611. Any idea what number they are?

 

[hifonics hugh]

Looks like what is written is on the transistors is WY 509 and UY 519.