JL Audio 500/1

[S Merlington]

With no outputs installed in the amp..

Heres what i get on the gate pads for the outputs..

Scope settings are : 5us 2 volts/div

Q505,Q506 is in pic 1


Q504,Q507 scope settings are 5us .5 volts div


Do these drive signals appear correct or do i have a problem somewhere?

 

[Perry Babin]

Do you have the low-side FETs shorted leg 2-3?

If so, the high-side drive is not right.

 

[S Merlington]

No I didn't have them shorted together ..

Which ones are the low side gets

 

[Perry Babin]

See attached.

 

[S Merlington]

With the low side fets shorted 2 to 3 heres what i get


Q504,Q506 is in the first pic

Scope set to 5us .2 volts.div

Q505,Q507

Scope set to 5us .2 volts div in 2nd pic

 

[Perry Babin]

With the same settings, touch your probe to a 12v power source, post an image of the scope's display with that DC displayed and post the measured DC voltage (with a multimeter).

 

[S Merlington]

Voltage is 13.89 volts

Same scope settings heres what i get if i touch the probe to the power wire..

 

[S Merlington]

Do the drive signals look ok or do I have a problem ?

 

[Perry Babin]

The first thing you have to do is get your scope reading correctly. As it is, the displayed waveforms are useless.

Go back through the oscilloscope page of the web site and set everything as suggested there. Also adjust the focus so that the trace is a fine line.

 

[S Merlington]

What controls the drive signal?

I don't get a drive signal on any of the pads for the outputs ..

 

[Perry Babin]

Until you get the scope working correctly, there's no point in going any farther with this.

 

[S Merlington]

I calibrated the scope last night and tested it out on a working amp..

Scope is working correctly now .

I tested the drive signal on this amp and have nothing ..