JL 500/1 V2 issue - 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 10th December 2012, 09:20 PM   #1
diyAudio Member
 
Join Date: Jun 2002
Location: non
Default JL 500/1 V2 issue

I ran into one of these with a blown up power supply, but the outputs were fine.

Replaced all transistors/resistors in the power supply circuit. Found an open R515 in the output stage for some reason, so i replaced that.

Now it works, plays with sound. But the amp idles at almost 3 amps and the toroid is getting really hot really fast.

Checked the drive signals going to the FETs and they are perfect. Also the outputs/power supply MOSFETS i left unclamped, and they are all getting just luke warm to the touch.

any ideas?
  Reply With Quote
Old 11th December 2012, 12:40 AM   #2
diyAudio Member
 
Join Date: Jun 2002
Location: non
anyone?

I should also note that I removed the toroid and ring tested it. It appears ok.
  Reply With Quote
Old 11th December 2012, 12:50 AM   #3
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
What is the frequency of oscillation on the tabs of the power supply FETs?
  Reply With Quote
Old 11th December 2012, 12:52 AM   #4
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Ring-testing toroids in car amps is VERY unreliable. When removing it, you will move the windings enough to open any shorted windings and it will appear to be OK. It's likely OK if it's not drawing excessive current (30+ amps). Ring testing is really only reliable for transformers that have fixed terminals or those potted in epoxy.
  Reply With Quote
Old 11th December 2012, 02:40 AM   #5
diyAudio Member
 
Join Date: Jun 2002
Location: non
Yea, it runs fine but its pulling about 3 amps idle. and the toroid starts overheating almost instantly, almost like the core is going into saturation. BUT the MOSFETs dont get hot.

Well, Another thing I noticed is even with the low pass filter turned off so the amp is running all-pass, it still sounds like lowpass with almost no highs. just less sharp on the true low pass. Ill check the frequency when I get back to the shop. The person who previously owned this amp, bought it new and purposely blew it up running full volume into 1 ohm load. Did it on purpose to see how long it would take to blow up. Idiots.
  Reply With Quote
Old 11th December 2012, 04:46 AM   #6
kds9591 is offline kds9591  United States
diyAudio Member
 
Join Date: Apr 2008
Location: Bensalem, PA
When ring testing a toroid you should not remove it, always test in circuit. As Perry said you may "correct" the shorted turns and it will test good.

You never stated the frequency you measured.

The outputs may have a marginal problem. There are only 4 of them, replaced them to eliminate them as a possible cause for your high idle current. If you have a good transistor tester compare the current gains (HFE) between the MOSFETS you remove with each other.
  Reply With Quote
Old 12th December 2012, 03:51 AM   #7
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Sometimes, the snubbers across the transformer windings will make a ringer useless. The purpose of the snubber is to damp any ringing on the windings. This will make the ringer see that there are insufficient rings after being pulsed and will indicate that the transformer is defective.
  Reply With Quote
Old 13th December 2012, 12:30 AM   #8
kds9591 is offline kds9591  United States
diyAudio Member
 
Join Date: Apr 2008
Location: Bensalem, PA
I use the blue ring tester made by Ana Tek. It has a wide range testing range for the Q of a coil or transformer. It has a vertical row of 8 LEDS on its side that indicate the level of Q of the coil or xformer has. The more LEDS lit going up the side the higher level Q The top 3 LEDS are green to indicate good, below that are 2 yellow LEDS that indicate questionable, then 2 red LEDS to indicate bad. If no LEDS light then the coil or xformer has a direct short across it ( no rings).

I'm familiar with the snubber on the xformer primary side skewing the readings. My experience so far in using the ringer on the primary side with snubbers has been the yellow LEDS light. If I still really suspect the xformer I could lift a lead on the snubber resistor or cap to get it out of circuit and recheck it. I have yet to do that. Those that test in the yellow range but are good I make a note of it for that make and model of amp for future reference. The ringer does have a limitation in that regard but if you adjust for that it is not a issue.

I will not say with 100% confidence that every coil , inductor or xformer that tests bad ( ex a inductor with only 10 turns) with the ringer truly is bad in all cases but I can say with 100% confidence that every coil or xformer that tests good is. So even if the ringer was only useful in knowing if a coil or xformer was truly good it is well worth the $60.00 investment to have on a tech's bench.

You ought to take a look at it Perry, for $60 (about a tank of gas) it can save a lot of bench time. They also sell it in kit form for less. Link is below.

Ana Tek Corporation
  Reply With Quote
Old 13th December 2012, 03:16 AM   #9
diyAudio Member
 
Join Date: Jun 2002
Location: non
I did swap the toroid yesterday and it worked fine. Grabbed one from a parts V1.
  Reply With Quote
Old 13th December 2012, 05:27 AM   #10
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
#9:
Did the transformer show any signs of overheating?

Could you tell if the core was cracked?

#8:
I don't want people to go out and buy equipment that they don't need. I've been doing this for more than 25 years and I can tell you that I've never found a use for a ringer in car amps except for checking transformers or inductors with fixed terminals or those that were potted. In all that time, I've found only about 10 that were defective. Most showed signs that they overheated so they were obviously defective. When I repaired TVs, the ringers that I have were used regularly. That's simply not the case with car amps. If someone already has a good scope and a good multimeter (or two) and they want a ringer they can buy a ringer but they shouldn't all of a sudden expect it to make their life easier.
  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
burnt JL 500/1 v2 please help CarlosL Car Audio 17 1st April 2012 09:16 PM
JL Audio 500/1 mike49504 Car Audio 59 27th January 2012 03:07 PM
help repairing JL 500/5 splicer13 Car Audio 18 9th August 2010 05:12 AM
JL 500/5 Part identification issue???? Messerschmitt Car Audio 13 5th March 2009 09:28 PM
FS: JL 500/1 ($500 CAD located in GVA) Dynamix Lude Swap Meet 0 27th October 2004 03:21 AM


New To Site? Need Help?

All times are GMT. The time now is 01:07 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