Help with class D repair please - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 22nd October 2004, 03:07 PM   #1
xokia is offline xokia  United States
diyAudio Member
 
Join Date: Oct 2004
Default Help with class D repair please

I have a class D amplifier I am trying to repair. It just keeps blowing fusses. I replaced one of the transistors on the power supply side because it was leaking current when the amp wasn't turned on. The PWM is suppossed to be a fixed frequency varying duty cycle design. I have this this regulated to 12V 1.5 amps. When I turn it on the voltage goes down to 7V because its current limited. I can get it to start switching but at about a 50% duty cycle. I don't have a schematic for this amplifier so I am working in the dark here. Any suggestions.
  Reply With Quote
Old 25th October 2004, 05:31 PM   #2
diyAudio Member
 
Join Date: Apr 2004
Location: BC
hey there..im no expert, but you are right..it is current limiting..try check and see if the reference hiccups..also check the output rectifiers on the PSU...there has to be a leaky/SC semi somewhere...
  Reply With Quote
Old 25th October 2004, 09:45 PM   #3
xokia is offline xokia  United States
diyAudio Member
 
Join Date: Oct 2004
I'll try the output rectifiers. This is really bugging me because I know its something simple. Its like there is a dead short after the switching power supply. With no schematic its a real pain.
  Reply With Quote
Old 26th October 2004, 03:22 PM   #4
diyAudio Member
 
Join Date: Apr 2004
Location: BC
it could be the PSU too...maybe you can try to remove the power amplifier and test the power supply...since its a switcher, it needs a load to start..measure the input resistance of the ampl and use a high power resistor of the same value to load the PSU...then try and see if the psu is limiting...atleast this way you can eliminate one possibility
  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
Help Need To Repair Marantz Pm 94 Class A Amp seafire Solid State 18 23rd November 2009 08:47 AM
At wits end with class D repair! Help! NUTTTR Car Audio 31 22nd September 2007 01:59 PM
How about a round-up of Class A kit power amps, or collectable vintage class A? Brisso57 Solid State 4 14th February 2007 10:30 AM
Class A repair : where to start ? neototem Solid State 5 6th September 2004 10:41 AM


New To Site? Need Help?

All times are GMT. The time now is 10:39 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