punch 500x bias voltage - Page 2 - 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 1st March 2012, 10:54 PM   #11
diyAudio Member
 
Join Date: Jun 2010
Short which transistor?

IF i turn the port all the way counter clock wise the bias is 0.00v

If i try and set the bias it does not start at 0.01 It starts about 4.3mv and goes up and down.
  Reply With Quote
Old 2nd March 2012, 12:37 AM   #12
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The bias transistor is the one between the output transistors.

0.00 isn't good enough resolution. You need to state voltage to millivolts.
  Reply With Quote
Old 6th March 2012, 02:08 PM   #13
diyAudio Member
 
Join Date: Jun 2010
My meter shows mv only when it is set to auto range 0.0mv


With the bias port set fully counter clock wise.
Input switch set to 2ch and gain port full counter clock wise.
With emitter and collector short i get .0mv across emitter resistor
If i turn the gain port all the way up at full i get 13.5mv (unstable) across the emitter resistor.
If i set the input to 4ch i get .0mv even if i turn the gain port all the way to full
I think the input section have a problem
  Reply With Quote
Old 6th March 2012, 09:33 PM   #14
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
It sounds like the amp may be oscillating.

If possible, set the defective channel to low pass to see if that makes a difference. Remove the jumper on the bias transistor.
  Reply With Quote
Old 7th March 2012, 03:58 PM   #15
diyAudio Member
 
Join Date: Jun 2010
I try it in LP and HP no difference
  Reply With Quote
Old 7th March 2012, 04:03 PM   #16
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Are the legs for the frame of any of the front panes switches shorting to a trace? There was a problem with that on a few amps but I don't remember which ones. It caused strange problems.
  Reply With Quote
Old 7th March 2012, 10:12 PM   #17
diyAudio Member
 
Join Date: Jun 2010
I check all switchs and did not find any short.
  Reply With Quote
Old 7th March 2012, 10:14 PM   #18
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Do you have a scope?
  Reply With Quote
Old 7th March 2012, 10:17 PM   #19
diyAudio Member
 
Join Date: Jun 2010
not yet
  Reply With Quote
Old 8th March 2012, 03:47 AM   #20
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Do you have a large resistor that's about 2-4 ohms?
  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
Rockford Fosgate Punch 500x 4 channel seankane Car Audio 48 29th April 2011 11:46 PM
bias current on rockford punch 200.4 Ground Zero Car Audio 2 5th April 2010 06:06 PM
Punch 500aII rail voltage/Voutput brandes.cm Car Audio 11 14th January 2010 01:18 PM
Punch 500x part location? KyferEz Car Audio 10 30th September 2008 12:21 AM
bias voltage vs bias current woodturner-fran Tubes / Valves 3 25th February 2007 12:24 AM


New To Site? Need Help?

All times are GMT. The time now is 09:15 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