Crossfire amp help please cfa-602 - 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 April 2011, 03:23 PM   #1
diyAudio Member
 
Join Date: Jan 2011
Default Crossfire amp help please cfa-602

I have been working on this amp forever it is very simple class ab I can't believe I am having so much trouble with it. The amp goes on and off with only 11 volts 2 amps applied to it using a linear power supply to power it, that supply does not go over three amps, I have checked everything, with my scope, I have replaced all the pnp transistors out of tolerance, none of the zeneers show any leakage or any signs of getting hot, the amp looks brand new, I know the guy had to of crossed the positive and negative because of the transistors I replaced, I pulled the main zeneer the runs from positive and negative terminals on the amp it's fine shows no backwards continuity meaning using fluke meter with the leads crossed on the zenner, I have replaced a op amp that was out of tolerance but still should have been good, I have pulled every fet n as well as p channel and checked all the transistors running those fets the pnp ones. All the caps are good any ideas because I feel like a idiot lol. I have never had a amp give me this much trouble, that includes jl amps I can fix those np at all lol
  Reply With Quote
Old 17th April 2011, 10:53 PM   #2
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
What do you mean 'it goes on and off'?
  Reply With Quote
Old 17th April 2011, 11:13 PM   #3
diyAudio Member
 
Join Date: Jan 2011
I mean it pulls excessive current and the power supply shuts down at 3 amps then turns back on keeps doing the same thing
  Reply With Quote
Old 17th April 2011, 11:18 PM   #4
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Measure the DC voltage across each of the emitter resistors. Does one resistor or a group of resistors read greater than 0.000v DC.
  Reply With Quote
Old 18th April 2011, 03:43 AM   #5
diyAudio Member
 
Join Date: Jan 2011
I already checked all 0v. I have voltage at the rcas and voltage on the speaker outputs all -10v
  Reply With Quote
Old 18th April 2011, 04:14 AM   #6
diyAudio Member
 
Join Date: Jan 2011
Here are a couple pics of the amp
DSCN8365resize - My Photo Gallery

DSCN8364resize - My Photo Gallery
  Reply With Quote
Old 18th April 2011, 06:33 AM   #7
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
With the amp disconnected from everything, what's the resistance from the B+ terminal to the RCA shields?

From the non-bridging speaker terminals to the RCAs shields?
  Reply With Quote
Old 18th April 2011, 01:48 PM   #8
diyAudio Member
 
Join Date: Jan 2011
.2 ohms
  Reply With Quote
Old 18th April 2011, 01:53 PM   #9
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
If you have 0.2 ohms from the B+ terminal to the RCA shields, the transformer is likely shorted. With the meter on those two points, twist the transformer to see if the resistance goes up significantly.
  Reply With Quote
Old 18th April 2011, 02:02 PM   #10
diyAudio Member
 
Join Date: Jan 2011
from the rca to the b+ is O/L from the non bridging speaker to rca is .2ohms
  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
crossfire cfa-602, car audio amp problem tuneman Car Audio 29 23rd September 2010 05:08 AM
crossfire cfa-602, car audio amp problem tuneman Solid State 1 11th September 2010 01:51 PM
crossfire amp mike49504 Car Audio 4 12th January 2010 07:49 AM
Crossfire vr1000D sub amp no1stunna Swap Meet 0 21st February 2009 08:59 PM
Mirand A1 CFA-Amp (Pictures) welcome comments ! pixworld Solid State 23 11th January 2005 11:22 AM


New To Site? Need Help?

All times are GMT. The time now is 12:18 PM.


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