JL Audio 500/1 v1 Rev. 10 Boards #2 - diyAudio
Go Back   Home > Forums > General Interest > Car Audio

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th September 2011, 12:14 AM   #1
RiLoWa is offline RiLoWa  United States
diyAudio Member
 
RiLoWa's Avatar
 
Join Date: Aug 2010
Location: Illinois
Default JL Audio 500/1 v1 Rev. 10 Boards #2

I am working on another 500/1 seperate from the one I posted about a few weeks earlier.

I replaced the IRFZ44's and their gate resistors and the IRF540's.

When I powered it up, it cycles on and off. Green LED will also shut off during the cycling. I am using a 5A fuse and 3 Ohm resistor in line with the B+. I know sometimes these amps are sensitive to having the resistor in line, so I removed it and it pops the 5A fuse right away. I checked for solder bridges and there are none. While checking resistances on the outputs, I find that the two inner pair of 540's seemed a little low compared to another amp (K Ohms instead of M Ohms) so I back tracked to U500 which looks like it has over heated and two resistors that don't measure right. R669 should be 10 Ohms but measures inconsistantly ~50K and the resistor next to it should be 100 Ohms and measures ~2.5K.

If I replace those parts, are they the only ones that are suspect considering the symptoms, or are there more areas I need to check?
Attached Images
File Type: jpg U500.JPG (733.7 KB, 185 views)
__________________
Tools - 1. TPI Scope Plus 440 2. B&K 2125 20MHz Dual Trace 3. Sorensen DCR20-50B 4. B&K 4011 5MHz Function Generator 5. Weller WESD51 6. A big hammer
  Reply With Quote
Old 17th September 2011, 12:53 AM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Remove the outputs and short the pins indicated in the attached photo. That should give you a clean square wave on the input to the MIC4427. Yo can then check the output signals.

If you have to replace it, removing the two adjacent capacitors makes it much easier.
Attached Images
File Type: jpg IMG_6951x.jpg (446.7 KB, 171 views)
  Reply With Quote
Old 17th September 2011, 01:35 AM   #3
RiLoWa is offline RiLoWa  United States
diyAudio Member
 
RiLoWa's Avatar
 
Join Date: Aug 2010
Location: Illinois
With the scope set to 5V div and 5mS div, I get two solid traces at 0 and +5VDC on both inputs and one solid trace at +5VDC on the outputs of the 4427.

The amp continues to cycle on and off, but after several cycles it quits and apears to remain on. I haven't measured the current draw at this point, but the power supply's analog panel meter indicates ~2A. The inline resistor is hot to touch.
__________________
Tools - 1. TPI Scope Plus 440 2. B&K 2125 20MHz Dual Trace 3. Sorensen DCR20-50B 4. B&K 4011 5MHz Function Generator 5. Weller WESD51 6. A big hammer
  Reply With Quote
Old 17th September 2011, 02:15 AM   #4
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Are you saying you get two lines using a single input on the scope?

If so, set the time base to ~10us and adjust the trigger level to see if you can get a lock.
  Reply With Quote
Old 17th September 2011, 02:31 AM   #5
RiLoWa is offline RiLoWa  United States
diyAudio Member
 
RiLoWa's Avatar
 
Join Date: Aug 2010
Location: Illinois
OK, scope set to 5us div. AND AC coupling, I have a nice square wave on both inputs.
On Output A (Pin7) I have a sawtooth waveform.
On Output B (Pin5) I have +5VDC
__________________
Tools - 1. TPI Scope Plus 440 2. B&K 2125 20MHz Dual Trace 3. Sorensen DCR20-50B 4. B&K 4011 5MHz Function Generator 5. Weller WESD51 6. A big hammer
  Reply With Quote
Old 17th September 2011, 02:35 AM   #6
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
It appears to be defective , assuming that you have supply voltage on the IC.

Use this to continue troubleshooting until you get a clean signal all of the way to the outputs. For the high-side FETs, you'll have to connect the source legs to ground to see the square wave. This is ONLY to be done with no outputs in the circuit.
  Reply With Quote
Old 17th September 2011, 02:47 AM   #7
RiLoWa is offline RiLoWa  United States
diyAudio Member
 
RiLoWa's Avatar
 
Join Date: Aug 2010
Location: Illinois
I do have +15V on Pin6 of the 4427.

So, replace the 4427 and the two resistors for sure.

When I look up the data sheet for this MIC4427BM I see it shows a delay time of 40ns. There are several varieties of this chip with different delay timings, does it matter with how it used here?

I have to order the 4427, are there other things that I need to verify now so I can put in one order?
__________________
Tools - 1. TPI Scope Plus 440 2. B&K 2125 20MHz Dual Trace 3. Sorensen DCR20-50B 4. B&K 4011 5MHz Function Generator 5. Weller WESD51 6. A big hammer
  Reply With Quote
Old 17th September 2011, 02:55 AM   #8
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
You can check the high-side drivers by confirming that you have a good signal to the gates of the high-side FETs.

Order the 4427 that has the same part number.
  Reply With Quote
Old 17th September 2011, 03:35 AM   #9
RiLoWa is offline RiLoWa  United States
diyAudio Member
 
RiLoWa's Avatar
 
Join Date: Aug 2010
Location: Illinois
Here is what I have on the high side gates:
5V Div. Probe x10, 5us Div.
Attached Images
File Type: jpg High Side Output Gate #1.JPG (697.3 KB, 153 views)
File Type: jpg High Side Output Gate #2.JPG (789.6 KB, 126 views)
__________________
Tools - 1. TPI Scope Plus 440 2. B&K 2125 20MHz Dual Trace 3. Sorensen DCR20-50B 4. B&K 4011 5MHz Function Generator 5. Weller WESD51 6. A big hammer
  Reply With Quote
Old 17th September 2011, 03:39 AM   #10
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Did you ground the 3rd leg of the high-side FETs?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
JL Audio 500/1 v1 Rev. 10 Board RiLoWa Car Audio 40 11th October 2011 02:19 AM
JL Audio 500/1 mike49504 Car Audio 55 23rd September 2011 05:26 AM
Can I run a 10 inch JL audio and a 12 inch JL audio off same amp ash4kel Car Audio 2 8th April 2011 02:12 AM
JL Audio 500/1 mike49504 Car Audio 1 15th August 2010 09:02 PM
jl audio 500/1 megael9 Car Audio 12 28th May 2010 11:01 PM


New To Site? Need Help?

All times are GMT. The time now is 03:55 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2