RF punch 800a2 channel repair question - 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 6th May 2013, 03:38 AM   #1
chipper is offline chipper  United States
diyAudio Member
 
Join Date: Oct 2008
Location: Los Angeles
Send a message via MSN to chipper Send a message via Yahoo to chipper
Default RF punch 800a2 channel repair question

Hi forum, I recently bought a punch 800a2 not sure of the board rev # still waiting for it to come. Anyway I wanted to know is it hard to repair the channels on these? This one has one blown channel (according to the seller) I've never repaired one of the larger RF amps before.

What components in the shorted channel would need to replaced in order to get it working?
Attached Images
File Type: jpg image.jpg (144.4 KB, 74 views)
__________________
Feel the PUNCH
  Reply With Quote
Old 6th May 2013, 03:40 AM   #2
chipper is offline chipper  United States
diyAudio Member
 
Join Date: Oct 2008
Location: Los Angeles
Send a message via MSN to chipper Send a message via Yahoo to chipper
Picture he sent me of the channel, you can see discoloration on the source resistors.
Attached Images
File Type: jpg image.jpg (137.8 KB, 69 views)
__________________
Feel the PUNCH
  Reply With Quote
Old 6th May 2013, 03:53 AM   #3
diyAudio Member
 
seankane's Avatar
 
Join Date: May 2010
Location: Washington State
When you get it re-post and I will help you. No sense in writing up long post about what "could" be wrong.

Likely it has shorted outputs, as well as some defective source resistors.

You will need to replace all the outputs and source resistors in the channel.

You will also need to check/replace any gate resistors for the output FETS.

If any of the source resistors are open you will likely have protection circuit issues to deal with.

You will have to check the various 1A and 2A transistors, and the 5D and A7 diodes for leaks or shorts.

There is also some 20 ohm resistors that usually need replaced in the channel as well.

Call Rockford get the schematic and re-post when you get it.
__________________
Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch
  Reply With Quote
Old 9th May 2013, 09:24 PM   #4
chipper is offline chipper  United States
diyAudio Member
 
Join Date: Oct 2008
Location: Los Angeles
Send a message via MSN to chipper Send a message via Yahoo to chipper
Ok got it. Is Q8, Q7, Q6, Q5 suppose to run a little above warm?? The other side remains cool when just idling. And for the blown channel all of the source resistors where shot out and both 5 IRF640 & IRF9640 also shorted.
__________________
Feel the PUNCH
  Reply With Quote
Old 10th May 2013, 01:56 AM   #5
chipper is offline chipper  United States
diyAudio Member
 
Join Date: Oct 2008
Location: Los Angeles
Send a message via MSN to chipper Send a message via Yahoo to chipper
Quote:
Originally Posted by seankane View Post
When you get it re-post and I will help you. No sense in writing up long post about what "could" be wrong.

Likely it has shorted outputs, as well as some defective source resistors.

You will need to replace all the outputs and source resistors in the channel.

You will also need to check/replace any gate resistors for the output FETS.

If any of the source resistors are open you will likely have protection circuit issues to deal with.

You will have to check the various 1A and 2A transistors, and the 5D and A7 diodes for leaks or shorts.

There is also some 20 ohm resistors that usually need replaced in the channel as well.

Call Rockford get the schematic and re-post when you get it.

I need some help. Q8, Q7, Q6, Q5 run a little above warm when idling while the other side stays cool. What's causing this? Thanks
__________________
Feel the PUNCH
  Reply With Quote
Old 10th May 2013, 04:20 AM   #6
diyAudio Member
 
Join Date: Jun 2012
Have you turned the bias pots fully counter-clockwise??
  Reply With Quote
Old 10th May 2013, 04:41 AM   #7
diyAudio Member
 
seankane's Avatar
 
Join Date: May 2010
Location: Washington State
Quote:
Originally Posted by chipper View Post
I need some help. Q8, Q7, Q6, Q5 run a little above warm when idling while the other side stays cool. What's causing this? Thanks
Well if one whole channel was shorted then obviously you clipped the legs of the FETS to enable the amp to power and idle.

The side of the power supply that is still driving the enabled FETS will get warmer more quickly than the side that has the FETS clipped, especially if the board is not mounted in the sink.

It should take a little bit for them to get warm though. They should not be getting warm very quickly if the amp is just idling.
__________________
Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch
  Reply With Quote
Old 10th May 2013, 01:46 PM   #8
chipper is offline chipper  United States
diyAudio Member
 
Join Date: Oct 2008
Location: Los Angeles
Send a message via MSN to chipper Send a message via Yahoo to chipper
Quote:
Originally Posted by seankane View Post
Well if one whole channel was shorted then obviously you clipped the legs of the FETS to enable the amp to power and idle.

The side of the power supply that is still driving the enabled FETS will get warmer more quickly than the side that has the FETS clipped, especially if the board is not mounted in the sink.

It should take a little bit for them to get warm though. They should not be getting warm very quickly if the amp is just idling.
Yes I desoldered them from the board and all of the open source resistors (all of them were no good) didn't take out anything else. I also wiggled the transformer around didn't seem to do anything. One bank of fets get really warm when mounted tightly to the sink while the other side just chills. It's not making any sense to me. Both bias pots are turned down.

Weirdest thing is they start to heat up after a minute of being powered up. Could it possibly be the channel that failed? I also noticed a group of smd components get very hot on the failed channel.
__________________
Feel the PUNCH
  Reply With Quote
Old 10th May 2013, 05:53 PM   #9
diyAudio Member
 
seankane's Avatar
 
Join Date: May 2010
Location: Washington State
Which side is running hot, the side you removed the fets on or the remaining channel?
__________________
Pyramid 52 Amp Power Supply----Fluke 787 Processmeter----Tektronix 465 Scope----Velleman HPS40 Scope----Soldering Iron----Desoldering Iron----Hejet HJ 500-S Heatgun----DM4070 Digital LCR Meter----Propane Torch
  Reply With Quote
Old 10th May 2013, 05:55 PM   #10
chipper is offline chipper  United States
diyAudio Member
 
Join Date: Oct 2008
Location: Los Angeles
Send a message via MSN to chipper Send a message via Yahoo to chipper
Quote:
Originally Posted by seankane View Post
Which side is running hot, the side you removed the fets on or the remaining channel?
The side with the removed outputs. The other bank of fets of the power supply (right channel) runs cool.
__________________
Feel the PUNCH
  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 800a2 non working chipper Car Audio 8 27th May 2012 09:13 PM
Rockford Fosgate Punch 800a2 seankane Car Audio 3 25th June 2011 05:18 AM
Rockford Punch 800a2 seankane Car Audio 28 5th April 2011 01:27 AM
punch 800a2 $100?? chipper Car Audio 6 8th July 2010 06:21 AM
Assembly/mechanical question RF Punch 45HD gisewhcs Car Audio 6 19th February 2010 01:08 PM


New To Site? Need Help?

All times are GMT. The time now is 01:44 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