Rockford Fosgate 800.4 - Distortion Ch RR - Page 3 - 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 21st February 2013, 07:42 PM   #21
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
The 12v power supply that you're using to power the amp.
  Reply With Quote
Old 26th February 2013, 07:34 AM   #22
Witwe is offline Witwe  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Schwerin
Hi Perry,

the powersupply gives me a constant 12v voltage.
only when I connect the amp, it deflects down to about 11v when the caps are charging (it is a realy short time!)
all the other time, even the amp is playing the 100hz sine wave, the scope shows this:
Click the image to open in full size.

I have measured the channel again while the scope is adjusted :
RearLeft:
Click the image to open in full size.

RearRight:
Click the image to open in full size.

it lookes a little bit strange, doesn't it?
  Reply With Quote
Old 26th February 2013, 06:13 PM   #23
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
If this channel works 100% correctly with D302 out of the circuit, remove the following transistors, one at a time to see which one (when out of the circuit) allows the amp to produce clean audio.

Q315
Q316
Q317

Reinstall the transistor before removing and testing the next one.
  Reply With Quote
Old 27th February 2013, 07:27 AM   #24
Witwe is offline Witwe  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Schwerin
after removing q316 the sine wave lookes good.
so what should I do next?
q316 itself can't be the problem because I have changed it twice.
  Reply With Quote
Old 27th February 2013, 02:19 PM   #25
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
If you reinstall Q316 and remove R345 and R358 from the circuit, does that allow the amp to produce clean audio?
  Reply With Quote
Old 28th February 2013, 07:39 AM   #26
Witwe is offline Witwe  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Schwerin
yes, it looks good!

I have measured both resistors:

R345 - 39,3k Ohm
R358 - 39,5k Ohm
  Reply With Quote
Old 28th February 2013, 01:59 PM   #27
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Power up the amp and measure the DC voltage directly across the speaker terminals of this channel. Post the voltage.

Reinstall R345. Does the audio remain clean or is it distorted?

When testing, do you have the speakers connected, then apply power remote?
  Reply With Quote
Old 28th February 2013, 04:15 PM   #28
Witwe is offline Witwe  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Schwerin
the DC Voltage at Idle was 3,7mV.
I have also measured the other channels:

RL - 11,5mV
LF - 5,4mV
RF - 1,5mV

why do they differ so?

After reinstalling R345, the audio remains clean. until now I have only tested everything without load connected.
The amp draws 1,29A at idle.
when I connect a speaker, it increases to 2,13A but the audio is still clean.
  Reply With Quote
Old 28th February 2013, 04:28 PM   #29
Witwe is offline Witwe  Germany
diyAudio Member
 
Join Date: Dec 2010
Location: Schwerin
when Powering up the amp, RL, LF and RF are showing a 30mV DC voltage for a second.
when disconnecting the power it increases up to 300mV and then it slowly decreases till 0V.
the RR channel shows 1,38V when powering up and 1,30V when powering down!

EDIT:

the voltages above are what my multimeter shows me...

while a speaker is connected to the RR channel, I can hear a klick 1-2seconds after powering the amp.
I made a video how it lookes at the scope:

Rockford Fosgate 800.4 trouble with RR channel - YouTube

Last edited by Witwe; 28th February 2013 at 04:41 PM.
  Reply With Quote
Old 28th February 2013, 05:23 PM   #30
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
You can reinstall R358 as well.

Lift 2 legs of Q305 and Q306. Do you have any offset on the RR channel?
  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 800.2 seankane Car Audio 104 10th December 2012 02:13 AM
Rockford Fosgate Power 800.4 seankane Car Audio 71 17th January 2012 08:43 PM
Rockford Fosgate 800 a2 mike49504 Car Audio 1 8th July 2011 07:33 PM
Rockford Fosgate 800.2 Brain Fried Car Audio 2 16th April 2010 06:14 PM
Rockford Fosgate Power 800.4 lostamps Car Audio 6 2nd January 2008 01:21 PM


New To Site? Need Help?

All times are GMT. The time now is 01:32 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