Faulty C-Audio Pulse 4x300 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 2nd September 2009, 01:11 AM   #1
diyAudio Member
 
Join Date: Apr 2006
Location: Oxfordshire
Default Faulty C-Audio Pulse 4x300

I have a C-audio (now crown audio) Pulse 4x300 PA amplifier that has one channel faulty (channel 3)
Having spent probably 10 hours attempting to find the fault, I am stuck for what to do next.

The schematic for the amp is here on the 6th page down (sheet 3)

Now for what faults I have. firstly and I have no output on channel 3, all other channels work.

The clip light for channel 3 lights up at very low volume setting despite no output.

There is signal at the base of TR28, there is no signal at either the collector or emitter of TR28.

DC voltage on TR28: Base = 0, emitter = -4, collector = -73
Other channels DC voltage: Base = 0, emitter = +2, collector = -73

Collector of TR22 has DC voltage of +73 - other channels have +17

Measuring the DC on TR22's collector with circuit board earthed to plug causes the amp to shut down. If earth disconnected then noise can be heard from the speaker but does not shut down amp.

DC voltage on TR33 is 0.4 on every pin with earth disconnected. with earth connected then it shuts the amp down.
DC voltage on other channels equivalent to TR33 there is Base = 0.6, Collector = -1, emitter = +1.1

I have replaced TR52, TR42, TR41, TR26, TR28, TR40, TR39, TR22, TR21, TR12 and TR47
I have exchanged TR33 for another channel and problem stayed with channel 3.

I am now completely stuck so any help is greatly appreciated

Thanks,
Ollie
  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
Need advice on a faulty c audio ra3001!! dean ashmore Solid State 23 8th December 2010 08:24 PM
Cambridge Audio Dacmagic mk2 faulty, HELP!! Puggie Digital Source 11 6th January 2010 12:03 PM
Hi there cambridge audio a4 faulty in need of the wizzes help (X PRO ) please homertooties Solid State 31 30th January 2009 02:50 PM


New To Site? Need Help?

All times are GMT. The time now is 01:37 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