JL Audio 500/1

mike49504 · 2011-09-23 1:23 am

R513 measures 47.3 ohms

R514 measures 10.2 ohms

Pulled the diode and it measures 0.556 with the probes reversed i get OL

SO they all check good.

Dont know if its normal but in the board the diode reads 0.037

Perry Babin · 2011-09-23 1:40 am

If you set the meter to ohms, you should read 57 ohms across the diode pads.

mike49504 · 2011-09-23 2:17 am

57.4 ohms across the pads

Perry Babin · 2011-09-23 2:31 am

Does either inductor show any signs of overheating?

mike49504 · 2011-09-23 2:36 am

Perry Babin · 2011-09-23 2:40 am

Have you confirmed that you have a good drive signal for all of the FETs?

mike49504 · 2011-09-23 4:26 am

what should i set my scope to? i tryed different settings but cant seem to get anything

Perry Babin · 2011-09-23 4:51 am

Read the following thread. It covers this exactly.
http://www.diyaudio.com/forums/car-audio/196735-jl-audio-500-1-v1-rev-10-boards-2-a.html

mike49504 · 2011-09-23 5:28 am

Ok no matter where i set the scope i cannot get a square wave on the outputs of the MIC4427..

Pin 5 of the 4427 has 6.82 volts on it..

Pin 7 has 6.77 volts on it..

Perry Babin · 2011-09-23 5:40 am

What do you have on the input pins of the 4427?

mike49504 · 2011-09-23 5:51 am

PIN 2: 1.11

PIN 4:0.63

Perry Babin · 2011-09-23 5:52 am

You should be using the scope for this since you're looking for a square wave. What do you see there with the scope?

mike49504 · 2011-09-23 5:54 am

Nothing just a straight line on the scope..

Perry Babin · 2011-09-23 5:57 am

Did you short the pins on the op-amp as shown in the other thread?

mike49504 · 2011-09-23 5:59 am

Perry Babin · 2011-09-23 6:26 am

What do you have on the bases of Q4 and Q5?

You'll have to check them from the bottom of the board unless you've made a set of jumpers for the preamp board.

JL Audio 500/1

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