Help with waveform on rails - looks unregulated - 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 26th December 2011, 09:34 PM   #1
diyAudio Member
 
Join Date: Sep 2011
Default Help with waveform on rails - looks unregulated

Hello,

While troubleshooting a dead channel on a QED amp I put the scope on the rails and I get what looks like partially rectified waveform, plus 3 phases?

Is my scope broken?
I mean normally the scope works fine. Why 3 phases? Positive end of rectifier bridge shows large sine 1/2 waves. Negative shows smaller ones.

Thnanks.
Attached Images
File Type: jpg positive_rail.jpg (19.7 KB, 75 views)
File Type: jpg negative_rail.jpg (26.6 KB, 73 views)
  Reply With Quote
Old 26th December 2011, 10:56 PM   #2
JoelS is offline JoelS  United States
diyAudio Member
 
Join Date: Oct 2011
Location: New York New York
that kind of look on the scope has to do with the way the triggering is working. there can only be one voltage at any instant of time, but if you believe what the scope is telling you here then there is 3 different voltages at each instant. play with the trigger level, or use more time per division, this should clean up.

is that supposed to be the regulated voltage? maybe the main filter caps after the bridge are not working, or dead regulator

-Joel
  Reply With Quote
Old 27th December 2011, 01:22 AM   #3
diyAudio Member
 
Join Date: Dec 2005
Location: Buenos Aires
It's a triggering problem. Try setting the trigger source to LINE.
  Reply With Quote
Old 27th December 2011, 01:28 AM   #4
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
Yes the trigger is not working.
In the first pic looks like you have one shorted diode in the power supply bridge.
  Reply With Quote
Old 27th December 2011, 01:10 PM   #5
diyAudio Member
 
Join Date: Sep 2011
Thanks !
  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
Unregulated Power Supply maxseeley Vendor's Bazaar 1 18th October 2011 06:41 PM
Benefits/Drawbacks of Dual rails vs Single Rails buzzforb Pass Labs 2 25th May 2011 01:06 PM
Understanding unregulated PSU Nikon1975 Tubes / Valves 4 1st March 2010 04:06 AM
Unregulated PSU MarcH Solid State 8 8th June 2008 09:35 AM
+8V unregulated? PhantomBox Parts 1 15th February 2008 10:08 PM


New To Site? Need Help?

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